Method and system for determining distance between continuous entrances of main line of expressway under heterogeneous traffic flow

Abstract

The invention discloses a method and system for determining the distance between continuous entrances of a main line of an expressway under heterogeneous traffic flow, and the method comprises the following steps: S1, analyzing vehicle driving behaviors based on traffic flow data, and dividing the types of vehicles into manual driving vehicles and automatic driving vehicles; s2, constructing a lane changing behavior model corresponding to the lane changing scene based on a lane changing decision process; s3, adding the length of the acceleration lane in the upstream area and the distance of the confluence safety sight distance in the midstream area to obtain the distance between the continuous entrances; according to the method, methodological guidance can be provided for determining the main line continuous entrance distance under the heterogeneous traffic flow possibly occurring in an actual expressway, so that the traffic safety and the passing efficiency under the heterogeneous traffic flow are guaranteed.

Description

Technical Field

[0001] The invention relates to the field of expressway design, and in particular to a method and system for determining the spacing between consecutive entrances of an expressway main line under heterogeneous traffic flows. Background Art

[0002] With the continuous development of autonomous driving technology, autonomous driving vehicles will coexist with manually driven vehicles for a long time before they are fully deployed. The heterogeneous traffic flow composed of autonomous driving vehicles and manually driven vehicles will replace the single manually driven traffic flow. The mutual influence between manually driven vehicles and autonomous driving vehicles makes traffic operation face the challenge of adapting to heterogeneous traffic flow. The continuous entrance section of the main line of the expressway is one of the important nodes that affect the traffic operation of the expressway. Not only does it have merging and merging, but the section between the two entrances also has behaviors such as lane changing and following vehicles. The complex driving behavior makes it more difficult to reasonably design the continuous entrance section. The continuous entrance spacing is a key indicator for the design of continuous entrance sections. There are large differences between autonomous driving vehicles and manually driven vehicles. The driving behavior of vehicles in the continuous entrance section under the heterogeneous traffic flow environment will be more complicated. Therefore, the reasonable setting of the continuous entrance spacing is of great significance to improving traffic safety and traffic efficiency within the entire interchange range.

[0003] At present, when determining the value of the continuous entrance spacing, the parameter system of the Highway Route Design Specification (JTG D20-2017) is based on a single manually driven traffic flow, without considering the impact of autonomous vehicles, and the driving behavior of vehicles on the continuous entrance sections is not considered comprehensively. When determining the continuous entrance spacing, the continuous entrance spacing is mainly divided into the length of the acceleration lane and the merging safety sight distance, which is mostly focused on manually driven vehicles, and less consideration is given to the heterogeneous traffic flow environment, failing to fully reflect the mutual influence between vehicles in the heterogeneous traffic flow environment.

[0004] Driving behavior on continuous entrance sections under heterogeneous traffic flow environments is more complicated. We should further explore the impact of heterogeneous traffic flows on the value of the continuous entrance spacing of highways, and determine the continuous entrance spacing that can meet traffic safety and traffic efficiency under heterogeneous traffic flows. This can improve the safety of vehicle driving on continuous entrance sections of the main line and the traffic efficiency of road traffic, which has certain practical significance for the future construction of smart highways. Summary of the invention

[0005] The purpose of the present invention is to provide a method and system for determining the spacing between consecutive entrances of a highway main line under heterogeneous traffic flows, which can provide methodological guidance for determining the spacing between consecutive entrances of a highway main line under heterogeneous traffic flows that may occur in actual highways, so as to ensure traffic safety and traffic efficiency under heterogeneous traffic flows.

[0006] The method for determining the distance between consecutive entrances of a main line of a highway under heterogeneous traffic flow designed by the present invention to achieve one of the above purposes is special in that it comprises the following steps:

[0007] Step S1: acquiring traffic flow data in a heterogeneous traffic flow environment, analyzing vehicle driving behaviors based on the traffic flow data, and classifying vehicle types into manually driven vehicles and autonomous driving vehicles;

[0008] Step S2: dividing the lane changing scenarios according to the vehicle type of the lane changing vehicle and the vehicle type of the vehicle behind the lane changing target, determining the lane changing scenarios according to the penetration rate of the autonomous driving vehicles, analyzing the lane changing decision process based on the lane changing scenarios, dividing the lane changing decision process into position judgment, gap judgment, initial decision of the lane changing vehicle, decision of the vehicle behind the lane changing target lane and re-decision of the lane changing vehicle, and constructing a lane changing behavior model corresponding to the lane changing scenario based on the lane changing decision process;

[0009] Step S3: Calculate the length of the acceleration section of the upstream acceleration lane based on the vehicle acceleration and the vehicle merging speed, calculate the length of the gap determination section of the upstream acceleration lane based on the gap waiting distance and the gap adjustment distance, determine the length of the gradient section of the upstream acceleration lane based on a preset standard, add the length of the acceleration section of the upstream acceleration lane, the length of the gap determination section of the upstream acceleration lane and the length of the gradient section of the upstream acceleration lane to obtain the length of the upstream acceleration lane; calculate the reaction distance of the midstream merging safety sight distance based on the vehicle running speed and the vehicle reaction time, and calculate the length of the gradient section of the upstream acceleration lane based on a preset standard. The decision distance of the merging safety sight distance in the midstream area is calculated based on the vehicle running speed and the vehicle decision time. The lane changing distance of the merging safety sight distance in the midstream area or the deceleration distance of the merging safety sight distance in the midstream area is calculated based on the lane changing decision. The reaction distance of the merging safety sight distance in the midstream area, the decision distance of the merging safety sight distance in the midstream area and the lane changing distance of the merging safety sight distance in the midstream area or the deceleration distance of the merging safety sight distance in the midstream area are added together to obtain the distance of the merging safety sight distance in the midstream area. The length of the acceleration lane in the upstream area and the distance of the merging safety sight distance in the midstream area are added together to obtain the spacing of continuous entrances.

[0010] Preferably, the method for obtaining traffic flow data in a heterogeneous traffic flow environment in step S1 includes: using a drone to take aerial photos at fixed time intervals to collect video data of continuous entrance sections of the main line of the expressway, extracting trajectory data of each vehicle in the video data of the continuous entrance sections of the main line of the expressway through trajectory extraction software, setting different lane areas for the video data of the continuous entrance sections of the main line of the expressway, and obtaining traffic flow data in a heterogeneous traffic flow environment.

[0011] Preferably, different lane areas are set for the video data of the continuous entrance sections of the main line of the expressway, including: a main line inner lane, a main line outer lane, an upstream acceleration lane and a downstream acceleration lane.

[0012] Preferably, in step S2, lane changing scenarios are divided according to the vehicle type of the lane changing vehicle and the vehicle type of the vehicle behind the lane changing target lane, and the lane changing scenarios include:

[0013] The first lane-changing scenario: Both the vehicle type of the lane-changing vehicle and the vehicle type of the target lane behind are autonomous vehicles;

[0014] The second lane-changing scenario: the vehicle type of the lane-changing vehicle is an autonomous vehicle, and the vehicle type of the target lane is a manually driven vehicle;

[0015] The third lane-changing scenario: the vehicle type of the lane-changing vehicle is a manually driven vehicle, and the vehicle type of the vehicle behind the target lane is an autonomous driving vehicle;

[0016] The fourth lane-changing scenario: the vehicle type of the lane-changing vehicle and the vehicle type of the vehicle behind the lane-changing target are both manually driven vehicles;

[0017] In step S2, the lane change scenario is determined according to the penetration rate of the autonomous driving vehicle, wherein the expression of the penetration rate of the autonomous driving vehicle is:

[0018]

[0019] Among them, p 1 represents the penetration rate of autonomous vehicles in the lane where the lane-changing vehicle is located before changing lanes, p 2 represents the penetration rate of autonomous vehicles in the lane where the lane-changing vehicle is located after changing lanes, represents the traffic volume of the autonomous driving vehicle in the lane where the lane-changing vehicle was before changing lanes, represents the traffic volume of the autonomous driving vehicle in the lane after the lane-changing vehicle changes lanes, Q 1 represents the total traffic volume in the lane where the lane-changing vehicle is located before changing lanes, Q 2 Indicates the total traffic volume in the lane where the lane-changing vehicle is located after changing lanes.

[0020] Preferably, the lane changing decision process based on the lane changing scenario analysis in step S2 includes: calculating the acceptable gaps of the manually driven vehicle and the autonomous driving vehicle respectively based on the acceptable gap model; dividing the lane changing modes into direct lane changing, assisted lane changing and aggressive lane changing according to the difference in the degree of interaction between the manually driven vehicle and the autonomous driving vehicle; and dividing the lane changing intention of the lane changing vehicle into mandatory lane changing intention and arbitrary lane changing intention according to the lane position and traffic environment of the vehicle in the continuous entrance section.

[0021] Preferably, the expression of the acceptable gap model is:

[0022]

[0023] Among them, G 人(x) represents the acceptable gap for manually driven vehicles, G 自 (x) represents the acceptable gap of the autonomous vehicle, S max represents the critical acceptable gap required for direct lane change, S min represents the critical acceptable gap required for aggressive lane change, x represents the lane position of the lane-changing vehicle on the continuous entry segment, and x 1 Indicates the start point of the importable segment, x 2 Indicates the starting point of the gradient segment, x 3 Indicates the end point of the segment that can be imported, x 4 Indicates the end point of the midstream area.

[0024] Preferably, the expression for the length of the acceleration section of the acceleration lane in the upstream area in step S3 is:

[0025]

[0026] Among them, L 1 represents the length of the acceleration section of the upstream acceleration lane, v represents the vehicle running speed, η represents the rate of change of acceleration to vehicle running speed, v b Indicates the vehicle speed when merging, v a represents the vehicle running speed at the merging nose in the upstream area, ζ represents the acceleration when the vehicle running speed is 0;

[0027] In step S3, the length of the gap determination section of the upstream acceleration lane is divided into a gap waiting distance and a gap adjustment distance; wherein, the expression of the gap waiting distance is:

[0028]

[0029] Among them, l wait Indicates the gap waiting distance, Indicates the size of the nth gap in the outermost lane of the main line, L car Indicates the length of the vehicle body, v b Indicates the vehicle speed when the vehicle in the acceleration lane merges. Indicates the running speed of the vehicle in front of the nth gap in the outermost lane of the main line;

[0030] Among them, the gap adjustment distance expression is:

[0031]

[0032] Among them, L adjust Indicates the gap adjustment distance, S TF Indicates the safe distance that the vehicle in the acceleration lane should maintain with the vehicle ahead in the gap, L car Indicates the length of the vehicle body. represents the running speed of the vehicle in front of the nth gap in the outermost lane of the main line, v b Indicates the vehicle running speed when the vehicle in the acceleration lane performs merging;

[0033] The length expression of the upstream acceleration lane gap determination section is:

[0034] L 2 = l wait +l adjust ;

[0035] Among them, L 2 represents the length of the upstream acceleration lane gap determination segment, l wait Indicates the gap waiting distance, l adjust Indicates the gap adjustment distance;

[0036] The expression for the length of the upstream acceleration lane in step S3 is:

[0037] L J =L 1 +L 2 +L 3 ;

[0038] Among them, L J Indicates the length of the upstream acceleration lane, L 1 Indicates the length of the acceleration section of the upstream acceleration lane, L 2 represents the length of the upstream acceleration lane clearance determination segment, L 3 Indicates the length of the acceleration lane transition section in the upstream area.

[0039] Preferably, the reaction distance expression of the midstream merging safety sight distance in step S3 is:

[0040] L 4 =v c t r ;

[0041] Among them, L 4 The reaction distance representing the safe sight distance for merging in the midstream area, v c Indicates the vehicle speed at the starting point of the outermost lane of the main line in the midstream area, t r Indicates vehicle reaction time;

[0042] The decision distance expression of the safe sight distance for merging in the midstream area in step S3 is:

[0043] L 5 =v c t d ;

[0044] Among them, L 5 represents the decision distance of the safe sight distance for merging in the midstream area, vc Indicates the vehicle speed at the starting point of the outermost lane of the main line in the midstream area, t d represents the vehicle decision time;

[0045] The lane-changing distance of the midstream merging safety sight distance or the deceleration distance of the midstream merging safety sight distance in step S3 is expressed as:

[0046]

[0047] Among them, L 6 Indicates the lane-changing distance for the midstream merging safety sight distance or the deceleration distance for the midstream merging safety sight distance, S TF Indicates the safe lane-changing distance between the lane-changing vehicle and the vehicle in front of the target lane, L car represents the vehicle body length, τ represents the execution time of the vehicle lane change, v c Indicates the vehicle speed at the starting point of the outermost lane of the main line in the midstream area. It represents the running speed of the vehicle in the outermost lane of the midstream area after the vehicle makes a reaction decision and the vehicle in front of the first gap in the inner lane, K 1 Indicates the time for gap elimination, K 2 Indicates the time when the braking force increases;

[0048] The distance expression of the safe sight distance for merging in the midstream area in step S3 is:

[0049] L H =L 4 +L 5 +L 6 ;

[0050] Among them, L H Indicates the safe sight distance for merging in the midstream area, L 4 The reaction distance, L, represents the safe sight distance for merging in the midstream area. 5 The decision distance for the safe sight distance of merging in the midstream area, L 6 It indicates the lane changing distance for the safe sight distance for merging in the midstream area or the deceleration distance for the safe sight distance for merging in the midstream area.

[0051] The system for determining the distance between consecutive entrances of the main line of a highway under heterogeneous traffic flow designed by the present invention to achieve the second objective above is special in that it includes:

[0052] A traffic flow data acquisition module, used to acquire traffic flow data in a heterogeneous traffic flow environment, analyze vehicle driving behavior based on the traffic flow data, and classify vehicle types into manually driven vehicles and autonomous driving vehicles;

[0053] A lane-changing behavior model construction module is used to divide lane-changing scenarios according to the vehicle type of the lane-changing vehicle and the vehicle type of the vehicle behind the lane-changing target lane, determine the lane-changing scenario according to the penetration rate of the autonomous driving vehicle, analyze the lane-changing decision process based on the lane-changing scenario, divide the lane-changing decision process into position judgment, gap judgment, initial decision of the lane-changing vehicle, decision of the vehicle behind the lane-changing target lane and re-decision of the lane-changing vehicle, and construct a lane-changing behavior model corresponding to the lane-changing scenario based on the lane-changing decision process;

[0054] The spacing calculation model construction module is used to calculate the length of the acceleration section of the upstream acceleration lane based on the vehicle acceleration and the vehicle merging speed, calculate the length of the gap determination section of the upstream acceleration lane based on the gap waiting distance and the gap adjustment distance, determine the length of the gradient section of the upstream acceleration lane based on the preset standard, and add the length of the acceleration section of the upstream acceleration lane, the length of the gap determination section of the upstream acceleration lane and the length of the gradient section of the upstream acceleration lane to obtain the length of the upstream acceleration lane; calculate the reaction time of the midstream merging safe sight distance based on the vehicle running speed and the vehicle reaction time Distance, calculate the decision distance of the merging safety sight distance in the midstream area based on the vehicle running speed and the vehicle decision time, calculate the lane changing distance of the merging safety sight distance in the midstream area or the deceleration distance of the merging safety sight distance in the midstream area based on the lane changing decision, add the reaction distance of the merging safety sight distance in the midstream area, the decision distance of the merging safety sight distance in the midstream area and the lane changing distance of the merging safety sight distance in the midstream area or the deceleration distance of the merging safety sight distance in the midstream area to obtain the distance of the merging safety sight distance in the midstream area; add the length of the acceleration lane in the upstream area and the distance of the merging safety sight distance in the midstream area to obtain the spacing of consecutive entrances.

[0055] A computer program product designed by the present invention to achieve the third objective mentioned above includes computer instructions, and the computer instructions are used to enable a computer to execute the above-mentioned method for determining the continuous entrance spacing of a highway main line under heterogeneous traffic flow.

[0056] The present invention has the following beneficial effects:

[0057] (1) The method and system for determining the spacing between consecutive entrances on the main line of a highway under heterogeneous traffic flow considers the differences in vehicle driving behaviors in a mixed traffic environment of manually driven vehicles and autonomous vehicles. By distinguishing vehicle types and lane-changing scenarios, a lane-changing behavior model that is more in line with the actual traffic flow characteristics is constructed. Furthermore, the lane-changing scenarios are analyzed and determined based on the lane-changing decision process (position judgment, gap judgment, initial decision of lane-changing vehicles, decision of the vehicle behind the target lane, and re-decision of lane-changing vehicles) and the penetration rate of autonomous vehicles. Compared with the traditional spacing determination method that only considers a single vehicle type, it can more accurately capture the interaction and lane-changing behavior of different types of vehicles in heterogeneous traffic flows, thereby improving the accuracy and reliability of the main line continuous entrance spacing determination.

[0058] (2) The method and system for determining the continuous entrance spacing of the main line of the expressway under heterogeneous traffic flow considers the upstream acceleration lane and the merging safe sight distance in the midstream area when calculating the continuous entrance spacing; in the upstream area, not only the length of the acceleration section is considered, but also the length of the gap determination section is calculated by the gap waiting distance and the gap adjustment distance, and the length of the upstream acceleration lane gradient section is determined based on a preset standard, reflecting the actual needs of vehicles in the process of finding and adjusting to an acceptable gap; in the midstream area, the reaction distance, decision distance, and lane changing or deceleration distance are considered to ensure that merging vehicles have sufficient safe sight distance; this comprehensive entrance spacing calculation can more comprehensively guarantee vehicle driving safety and road traffic efficiency compared with the traditional method that only considers a single factor (such as only considering the acceleration distance). BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 A schematic flow chart of a method for determining the distance between consecutive entrances of a main line of a highway under heterogeneous traffic flow according to an embodiment of the present invention is shown.

[0060] Figure 2 A schematic diagram showing the difference in relative speed and acceleration between a manually driven vehicle and an autonomous driving vehicle according to an embodiment of the present invention is shown.

[0061] Figure 3 A schematic diagram showing the difference in braking process between a manually driven vehicle and an automatically driven vehicle according to an embodiment of the present invention.

[0062] Figure 4 Schematic diagrams showing various lane changing scenarios according to embodiments of the present invention.

[0063] Figure 5 A schematic diagram showing changes in acceptable gaps according to an embodiment of the present invention.

[0064] Figure 6 A schematic diagram of a decision process for a first lane changing scenario according to an embodiment of the present invention is shown.

[0065] Figure 7 A schematic diagram showing a decision process of a second lane changing scenario according to an embodiment of the present invention is shown.

[0066] Figure 8 A schematic diagram showing a decision process for a third lane changing scenario according to an embodiment of the present invention is shown.

[0067] Fig. 9 A schematic diagram of a decision process for a fourth lane changing scenario according to an embodiment of the present invention is shown.

[0068] Fig.10 A schematic diagram showing the road segment composition of continuous entrance spacing according to an embodiment of the present invention.

[0069] Fig.11A schematic diagram showing the road segment definition of continuous entrance spacing according to an embodiment of the present invention.

[0070] Fig.12 A schematic diagram showing the length division of each section of the acceleration lane according to an embodiment of the present invention is shown.

[0071] Fig.13 A schematic diagram of the gap waiting process according to an embodiment of the present invention is shown.

[0072] Fig.14 A schematic diagram of a gap adjustment process according to an embodiment of the present invention is shown.

[0073] Fig.15 A schematic diagram showing the division of various distances of the merging safe sight distance according to an embodiment of the present invention is shown.

[0074] Fig.16 A schematic diagram of a scene showing the completion of the lane change decision stage according to an embodiment of the present invention.

[0075] Fig.17 A schematic diagram showing the difference in deceleration process between a manually driven vehicle and an automatically driven vehicle according to an embodiment of the present invention is shown.

[0076] Fig.18 A schematic flow chart of a continuous inlet spacing calculation model according to an embodiment of the present invention is shown.

[0077] Fig.19 A module schematic diagram of a system for determining the distance between consecutive entrances of a main line of a highway under heterogeneous traffic flow according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0078] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0079] Example 1

[0080] like Figure 1 As shown, an embodiment of the present invention provides a method for determining the distance between consecutive entrances of a main line of a highway under heterogeneous traffic flow, the method comprising the following steps:

[0081] Step S1: acquiring traffic flow data in a heterogeneous traffic flow environment, analyzing vehicle driving behaviors based on the traffic flow data, and classifying vehicle types into manually driven vehicles and autonomous driving vehicles;

[0082] Step S2: dividing the lane changing scenarios according to the vehicle type of the lane changing vehicle and the vehicle type of the vehicle behind the lane changing target, determining the lane changing scenarios according to the penetration rate of the autonomous driving vehicles, analyzing the lane changing decision process based on the lane changing scenarios, dividing the lane changing decision process into position judgment, gap judgment, initial decision of the lane changing vehicle, decision of the vehicle behind the lane changing target lane and re-decision of the lane changing vehicle, and constructing a lane changing behavior model corresponding to the lane changing scenario based on the lane changing decision process;

[0083] Step S3: Calculate the length of the acceleration section of the upstream acceleration lane based on the vehicle acceleration and the vehicle merging speed, calculate the length of the gap determination section of the upstream acceleration lane based on the gap waiting distance and the gap adjustment distance, determine the length of the gradient section of the upstream acceleration lane based on a preset standard, add the length of the acceleration section of the upstream acceleration lane, the length of the gap determination section of the upstream acceleration lane and the length of the gradient section of the upstream acceleration lane to obtain the length of the upstream acceleration lane; calculate the reaction distance of the midstream merging safety sight distance based on the vehicle running speed and the vehicle reaction time, and calculate the length of the gradient section of the upstream acceleration lane based on a preset standard. The decision distance of the merging safety sight distance in the midstream area is calculated based on the vehicle running speed and the vehicle decision time. The lane changing distance of the merging safety sight distance in the midstream area or the deceleration distance of the merging safety sight distance in the midstream area is calculated based on the lane changing decision. The reaction distance of the merging safety sight distance in the midstream area, the decision distance of the merging safety sight distance in the midstream area and the lane changing distance of the merging safety sight distance in the midstream area or the deceleration distance of the merging safety sight distance in the midstream area are added together to obtain the distance of the merging safety sight distance in the midstream area. The length of the acceleration lane in the upstream area and the distance of the merging safety sight distance in the midstream area are added together to obtain the spacing of continuous entrances.

[0084] Based on the above embodiment, the method for obtaining traffic flow data in a heterogeneous traffic flow environment in step S1 includes: using a drone to take aerial photos of continuous entrance sections of the main line of the expressway at intervals of ten minutes, collecting video data of the continuous entrance sections of the main line of the expressway, when performing statistical analysis on the overall traffic flow, the sample size is as shown in formula (1), and when performing statistical analysis on the 85% speed, the sample size is as shown in formula (2).

[0085]

[0086]

[0087] In formulas (1) and (2), n represents the minimum sample size, t represents the distribution statistic, and t=1.96 is taken as the 95% confidence level. σ represents the population standard deviation. When the population standard deviation is unknown, it is replaced by the sample standard deviation S. S represents the sample standard deviation. U represents the statistical type constant. For example, when the average vehicle speed is 0, the U of the 85% vehicle speed can be 1.04. E represents the allowable deviation accuracy. For example, the running speed error can be 2-5 km / h, and the E of the headway can be 1.5 s.

[0088] Through trajectory extraction software, such as DataFromSky, the origin of the collected coordinate system is set as the intersection of the right lane line of the outermost lane and the vertical line of the merging nose in the upstream area, and the x-axis is along the vehicle's forward direction and the y-axis is perpendicular to the vehicle's forward direction. The trajectory data of each vehicle in the video data of the continuous entrance section of the main line of the expressway is extracted. Different lane areas are set for the video data of the continuous entrance section of the main line of the expressway, including: the inner lane of the main line, the outer lane of the main line, the upstream acceleration lane and the downstream acceleration lane, so as to obtain traffic flow data under a heterogeneous traffic flow environment.

[0089] like Figure 2 As shown in the figure, the time period when the vehicle is in a stable following state in the data is selected for analysis, and the reaction time is calibrated using the relative speed and acceleration comparison diagram method. In the comparison diagram method, the peak and valley of the relative speed of the front and rear vehicles and the peak and valley of the acceleration of the following vehicle are exactly a pair of stimulus-response, and the delay between the peaks and valleys is the reaction time of the following vehicle; Figure 3 As shown, the process of automatic driving and manually driven vehicles starting to decelerate and brake is selected for analysis. The deceleration amplitude of manually driven vehicles during braking is larger and the braking process is more rapid. In comparison, the deceleration amplitude of automatic driving vehicles during braking is more gradual. Under the same initial speed, the braking time required for manually driven vehicles is shorter. The differences in reaction time and braking process are used to analyze the difference between manually driven vehicles and automatic driving vehicles.

[0090] Based on the above embodiment, in step S2, the lane changing scenarios are divided according to the vehicle type of the lane changing vehicle and the vehicle type of the vehicle behind the lane changing target lane, such as Figure 4 As shown, the lane changing scenario includes:

[0091] The first lane-changing scenario: Both the vehicle type of the lane-changing vehicle and the vehicle type of the target lane behind are autonomous vehicles;

[0092] The second lane-changing scenario: the vehicle type of the lane-changing vehicle is an autonomous vehicle, and the vehicle type of the target lane is a manually driven vehicle;

[0093] The third lane-changing scenario: the vehicle type of the lane-changing vehicle is a manually driven vehicle, and the vehicle type of the vehicle behind the target lane is an autonomous driving vehicle;

[0094] The fourth lane-changing scenario: the vehicle type of the lane-changing vehicle and the vehicle type of the vehicle behind the lane-changing target are both manually driven vehicles;

[0095] Based on the above embodiment, in step S2, the lane change scenario is determined according to the penetration rate of the autonomous driving vehicle, wherein the expression of the penetration rate of the autonomous driving vehicle is shown in formula (3).

[0096]

[0097] In formula (3), p 1 represents the penetration rate of autonomous vehicles in the lane where the lane-changing vehicle is located before changing lanes, p 2 represents the penetration rate of autonomous vehicles in the lane where the lane-changing vehicle is located after changing lanes, represents the traffic volume of the autonomous driving vehicle in the lane where the lane-changing vehicle was before changing lanes, represents the traffic volume of the autonomous driving vehicle in the lane after the lane-changing vehicle changes lanes, veh / h, Q 1 represents the total traffic volume in the lane where the lane-changing vehicle is located before changing lanes, Q 2 It indicates the total traffic volume in the lane where the lane-changing vehicle is located after changing lanes, veh / h.

[0098] Based on the above embodiment, the lane changing decision process based on the lane changing scenario analysis in step S2 includes: based on the acceptable gap model, respectively calculating the acceptable gaps of the manually driven vehicle and the autonomous driving vehicle; according to the difference in the degree of interaction between the manually driven vehicle and the autonomous driving vehicle, dividing the lane changing modes into direct lane changing, assisted lane changing and aggressive lane changing; according to the lane position of the vehicle in the continuous entrance section and the traffic environment, dividing the lane changing intention of the lane changing vehicle into mandatory lane changing intention and arbitrary lane changing intention.

[0099] This embodiment is for expressways, and the part of the acceleration lane that can be merged except the gradual transition section is divided into three sections. The acceptable gap of manually driven vehicles changes twice, while the acceptable gap of autonomous driving vehicles changes linearly. At the same time, the acceptable gap of vehicles in the midstream area does not change with the change of position. The change trend of the acceptable gap, such as Figure 5 shown.

[0100] The expressions of the acceptable gap model are shown in equations (4) and (5).

[0101]

[0102] In formula (4) and (5), G 人 (x) represents the acceptable gap of a manually driven vehicle, m, G 自 (x) represents the acceptable gap of the autonomous vehicle, m, S max represents the critical acceptable gap required for direct lane change, m, S min represents the critical acceptable gap required for aggressive lane change, m, x represents the lane position of the lane-changing vehicle on the continuous entry segment, m, x 1 Indicates the starting point of the importable segment, m, x 2 Indicates the starting point of the gradient segment, m, x 3 Indicates the end point of the segment that can be imported, m, x 4 Indicates the end point of the midstream area, m.

[0103] According to the vehicle interaction process, the lane changing decisions in four lane changing scenarios are analyzed separately:

[0104] In the first lane-changing scenario, the vehicle type of the lane-changing vehicle and the vehicle type of the target lane behind are both autonomous vehicles. The lane-changing decision process of the lane-changing vehicle is as follows: Figure 6 As shown in the figure, in the first lane-changing scenario, according to the different decisions made by the lane-changing vehicle and the vehicle behind the target lane at each stage, there are three types of lane-changing behaviors: direct lane-changing, assisted lane-changing, and aggressive lane-changing.

[0105] When the vehicle is in x 1 ≤x <x 2 When the target lane gap satisfies G>S max , the lane-changing vehicle performs a direct lane change; if the target lane gap satisfies S min ≤G max , the lane change will affect the vehicle behind the target lane, then the lane-changing vehicle performs an assisted lane change;

[0106] When the vehicle is in x 2 ≤x <x 3 When the lane is in the acceleration lane transition section, the lane change urgency is high. As long as the target lane gap satisfies G>S min , the lane-changing vehicle performs an aggressive lane change.

[0107] In the second lane-changing scenario, the vehicle type of the lane-changing vehicle is an autonomous vehicle, and the vehicle type of the target lane is a manually driven vehicle. The lane-changing decision process of the lane-changing vehicle is as follows: Figure 7 As shown in the figure; in the second lane-changing scenario, according to the different decisions made by the lane-changing vehicle and the vehicle behind the target lane at each stage, there are four behaviors: direct lane-changing, assisted lane-changing, aggressive lane-changing and lane-changing failure;

[0108] When the vehicle is in x 1 ≤x <x 2 When the target lane gap satisfies G>S max , the lane-changing vehicle performs a direct lane change; if the target lane gap satisfies S min ≤G max , lane changing will have an impact on the vehicle behind the target lane. If the driver of the vehicle behind the target lane is a general or conservative driver, he will slow down and give way, and the lane changing vehicle will perform an assisted lane change; if the driver of the vehicle behind the target lane is an anxious driver, the lane changing request will be rejected, and the lane changing vehicle will give up the lane change and wait for the next gap;

[0109] When the vehicle is in x 2 ≤x <x 3 When the lane is in the acceleration lane transition section, the lane change urgency is high. As long as the target lane gap satisfies G>S​​min , the lane-changing vehicle performs an aggressive lane change.

[0110] In the third lane-changing scenario, the vehicle type of the lane-changing vehicle is a manually driven vehicle, the vehicle type of the vehicle behind the target lane is, and the lane-changing decision process of the lane-changing vehicle is as follows: Figure 8 As shown in the figure, in the third lane-changing scenario, according to the different decisions made by the lane-changing vehicle and the vehicle behind the target lane at each stage, there are four behaviors: direct lane-changing, assisted lane-changing, aggressive lane-changing, and lane-changing failure.

[0111] When the vehicle is in x 1 ≤x<(2x 1 +x 2 ) / 3, if the target lane gap satisfies G>G 人 (x), the lane-changing vehicle performs a direct lane change. If the target lane gap satisfies S min ≤G <G 人 (x) If the driver of the lane-changing vehicle is an anxious driver, the lane change will be executed. If the vehicle behind the target lane is an autonomous vehicle, it will slow down and yield, and the lane-changing vehicle will perform an assisted lane change. If the driver of the lane-changing vehicle is a general or conservative driver, the lane change will be abandoned and the next gap will be waited for.

[0112] When the vehicle is in (2x 1 +x 2 ) / 3≤x<(x 1 +2x 2 ) / 3, if the target lane gap satisfies G>G 人 (x), the lane-changing vehicle performs a lane change, which will affect the vehicle behind the target lane. However, if the vehicle behind the target lane is an autonomous vehicle and chooses to slow down and give way, the lane-changing vehicle performs an assisted lane change. If the target lane gap satisfies S min ≤G <G 人 (x), the acceptable gap meets the gap requirement of aggressive lane change. If the driver of the lane-changing vehicle is an anxious driver or a general driver, the lane change will be executed and an aggressive lane change will be performed; if the driver of the lane-changing vehicle is a conservative driver, the lane change will be abandoned and the next gap will be waited for;

[0113] When the vehicle is in (x 1 +2x 2 ) / 3≤x <x 3 When the target lane gap satisfies G>G 人 (x), the acceptable gap meets the gap requirement for aggressive lane change. Since it is at the end of the acceleration lane, the lane change urgency is relatively high. As long as the target lane gap satisfies G>S min , the lane-changing vehicle performs an aggressive lane change.

[0114] In the fourth lane-changing scenario, the vehicle type of the lane-changing vehicle and the vehicle type of the target lane behind are both manually driven vehicles. The lane-changing decision process of the lane-changing vehicle is as follows: Fig. 9 As shown in the figure; in the fourth lane-changing scenario, according to the different decisions made by the lane-changing vehicle and the vehicle behind the target lane at each stage, there are four behaviors: direct lane-changing, assisted lane-changing, aggressive lane-changing and lane-changing failure;

[0115] When the vehicle is in x 1 ≤x<(2x 1 +x 2 ) / 3, if the target lane gap satisfies G>G 人 (x), the lane-changing vehicle performs a direct lane change. If the target lane gap satisfies S min ≤G <G 人 (x) If the driver of the lane-changing vehicle is an anxious driver, the lane change will be executed. If the driver of the vehicle behind the target lane is an average driver or a conservative driver, the lane-changing vehicle will slow down and yield, and the lane-changing vehicle will perform an assisted lane change. If the driver of the vehicle behind the target lane is an anxious driver, the lane-changing request will be rejected and the lane-changing vehicle will give up the lane change. If the driver of the lane-changing vehicle is an average driver or a conservative driver, the lane-changing vehicle will give up the lane change and wait for the next gap.

[0116] When the vehicle is in (2x 1 +x 2 ) / 3≤x<(x 1 +2x 2 ) / 3, if the target lane gap satisfies G>G 人 (x), the lane-changing vehicle executes the lane change, which will have an impact on the vehicle behind the target lane. If the driver of the vehicle behind the target lane is a general or conservative driver, he will slow down and give way, and the lane-changing vehicle will perform an assisted lane change. If the driver of the vehicle behind the target lane is an anxious driver, the lane change request will be rejected and the lane-changing vehicle will give up the lane change. If the target lane gap satisfies S min ≤G <G 人 (x), the acceptable gap meets the gap requirement of aggressive lane change. If the driver of the lane-changing vehicle is an anxious driver or a general driver, the lane change will be executed. If the driver of the vehicle behind the target lane is a general driver or a conservative driver, the lane-changing vehicle will slow down and give way, and the lane-changing vehicle will perform an assisted lane change. If the driver of the vehicle behind the target lane is an anxious driver, the lane-changing request will be rejected and the lane-changing vehicle will give up the lane change. If the driver of the lane-changing vehicle is a conservative driver, the lane-changing vehicle will give up the lane change and wait for the next gap.

[0117] When the vehicle is in (x 1 +2x 2 ) / 3≤x <x 3 When the target lane gap satisfies G>G 人(x), the acceptable gap meets the gap requirement for aggressive lane change. Since it is at the end of the acceleration lane, the lane change urgency is relatively high. As long as the target lane gap satisfies G>S min , the lane-changing vehicle performs an aggressive lane change.

[0118] like Fig.10 As shown in the figure, according to the driving requirements of vehicles on the continuous entrance sections, the continuous entrance spacing is divided into two parts: the length of the acceleration lane in the upstream area and the distance of the merging safety sight distance in the midstream area.

[0119] like Fig.11 As shown in the figure, the part where solid lines are drawn and merging is prohibited is called the isolation section, and the part where dashed lines are drawn and vehicles in the acceleration lane are allowed to merge into the main line is called the merging section.

[0120] like Fig.12 As shown in the figure, according to the driving behavior, the acceleration lane isolation segment is defined as the acceleration segment, and the part of the mergeable segment other than the gradient segment is called the gap determination segment. The length of the acceleration lane consists of the acceleration segment, the gap determination segment and the gradient segment.

[0121] In this embodiment, a calculation model for the length of the acceleration segment is constructed based on a linear variation model of acceleration.

[0122] Based on the above embodiment, the expression for the length of the acceleration section of the acceleration lane in the upstream area in step S3 is as shown in formula (6).

[0123]

[0124] In formula (6), L 1 represents the length of the acceleration section of the upstream acceleration lane, m, v represents the vehicle speed, m / s, and η represents the rate of change of acceleration to vehicle speed, m / s 3 , v b Indicates the vehicle speed when merging, m / s, v a represents the vehicle speed at the upstream merge nose, m / s, and ζ represents the acceleration when the vehicle speed is 0, m / s 2 .

[0125] like Fig.13 As shown in the figure, after the vehicle in the acceleration lane passes the acceleration section, the gap determination process begins; the first gap in the outermost lane of the main line is judged. If the lane change condition is met, the gap adjustment is performed to execute the lane change; if the lane change condition is not met, the current gap is abandoned, and the second gap in the outermost lane of the main line is waited for, and the lane change condition is judged again. The distance traveled by the vehicle in the acceleration lane while waiting for an acceptable gap to appear before entering the gap adjustment stage is the gap waiting distance.

[0126] like Fig.14As shown, if the acceleration lane vehicle R is in the first gap When changing lanes, the gap waiting distance is 0; if in the second gap To change lanes, the gap waiting distance is the distance traveled when vehicle R and vehicle 2 are in the same section; if When changing lanes, the gap waiting distance is the distance that vehicle L and vehicle n travel when they are in the same section.

[0127] Based on the above embodiment, the length of the gap determination section of the upstream acceleration lane in step S3 is divided into a gap waiting distance and a gap adjustment distance; wherein the expression of the gap waiting distance is shown in formula (7).

[0128]

[0129] In formula (7), l wait Indicates the gap waiting distance, m, Indicates the size of the nth gap in the outermost lane of the main line, m, L car Indicates the length of the vehicle body, m, v b Indicates the vehicle speed when the vehicle in the acceleration lane merges, m / s, Indicates the running speed of the vehicle in front of the nth gap in the outermost lane of the main line, m / s;

[0130] When the vehicle in the acceleration lane passes the gap waiting stage and determines that a gap in the outermost lane of the main line can be used for lane change, it needs to adjust its position relationship with the gap so that it and the vehicle in front of the gap meet the conditions for safe lane change. The distance traveled by the vehicle in this process is the gap adjustment distance.

[0131] During the gap adjustment process, the acceleration lane vehicle R should be adjusted to a distance S from the nth vehicle in the outermost lane of the main line. TF distance.

[0132] The gap adjustment distance expression is shown in formula (8).

[0133]

[0134] In formula (8), l adjust Indicates the gap adjustment distance, m, S TF Indicates the safe distance that the vehicle in the acceleration lane should maintain with the vehicle in front of the gap, m, L car Indicates the length of the vehicle body, m, Indicates the running speed of the vehicle in front of the nth gap in the outermost lane of the main line, m / s, v b Indicates the vehicle running speed when the vehicle in the acceleration lane performs merging, m / s;

[0135] The length expression of the upstream acceleration lane gap determination section is shown in formula (9).

[0136]

[0137] In formula (9), L 2 Indicates the length of the upstream acceleration lane gap determination segment, m, l wait Indicates the gap waiting distance, m, l adjust Indicates the gap adjustment distance, m;

[0138] Compared with manually driven vehicles, the steering operation of autonomous vehicles is more precise and smooth. Therefore, autonomous vehicles have good adaptability to the provisions on the length of the gradient section in the "Highway Grade Separation Design Regulations" (JTG / TD21-2014), and there is no need to modify it.

[0139] The "Highway Grade Separation Design Specifications" (JTG / TD21-2014) stipulates the length and gradient rate of the gradient section of the parallel acceleration lane, as shown in Table 1.

[0140] Table 1 Gradient length and gradient rate of the linear acceleration lane

[0141]

[0142] Based on the above embodiment, the expression for the length of the acceleration lane in the upstream area in step S3 is as shown in formula (10).

[0143] L J =L 1 +L 2 +L 3 (10)

[0144] In formula (10), L J Indicates the length of the acceleration lane in the upstream area, m, L 1 Indicates the length of the acceleration section of the upstream acceleration lane, m, L 2 Indicates the length of the upstream acceleration lane clearance determination segment, m, L 3 Represents the length of the acceleration lane transition section in the upstream area, m.

[0145] like Fig.15 As shown in the figure, by analyzing the driving behavior of vehicles that need to slow down or change lanes inward in the midstream area, it can be seen that the merging safe sight distance is composed of reaction distance, decision distance, lane changing or deceleration distance.

[0146] When there is a vehicle at the downstream entrance, the vehicles at the starting position of the outer lane in the midstream area will have a reaction phase. After the reaction phase, the presence of the vehicle at the downstream entrance is clear. The reaction phase is short, and it can be considered that the vehicle is traveling at a constant speed during this process.

[0147] Based on the above embodiment, the reaction distance expression of the midstream merging safety sight distance in step S3 is shown in formula (11).

[0148] L 4 =v c t r (11)

[0149] In formula (11), L 4 Represents the reaction distance of the safe sight distance of the merging in the midstream area, m, v c Indicates the vehicle speed at the starting point of the outermost lane of the main line in the middle reaches, m / s, t r represents the vehicle reaction time, s;

[0150] After the vehicle goes through the reaction process, it takes a certain amount of time to make a decision, that is, to take lane changing measures or deceleration measures. This process can be roughly considered as the vehicle traveling at a constant speed.

[0151] Based on the above embodiment, the decision distance expression of the midstream merging safety sight distance in step S3 is shown in formula (12).

[0152] L 5 =v c t d (12)

[0153] In formula (12), L 5 Indicates the decision distance of the safe sight distance for merging in the midstream area, m, v c Indicates the vehicle speed at the starting point of the outermost lane of the main line in the middle reaches, m / s, t d represents the vehicle decision time, s, and t for manually driven vehicles in this embodiment d The value is 1.6s, and the t d The value is 0.5s;

[0154] like Fig.16 As shown, after the decision stage, if the first gap in the inner lane If the gap is acceptable, vehicle M adjusts its position relative to the gap and then changes lanes. If the lane-changing condition is not met, vehicle M takes deceleration measures and decelerates to the merging nose passing speed v at the downstream entrance. d , thereby avoiding conflicts with downstream entrance vehicles. Depending on the vehicle decision results, the distance required by the vehicle after the decision stage is also different.

[0155] By analyzing the driver's lane-changing method, it can be seen that when calculating the lane-changing distance, there is no need to consider the waiting gap process. It is only necessary to calculate the gap adjustment and the distance required for lane-changing execution. The expression of the lane-changing distance is shown in formula (13).

[0156]

[0157] In formula (13), S TF Indicates the safe lane-changing distance between the lane-changing vehicle and the vehicle in front of the target lane, m; L car represents the vehicle body length, m; τ represents the execution time of the vehicle lane change, s; v c Indicates the vehicle speed at the starting point of the outermost lane of the main line in the midstream area, m / s; It indicates the running speed of the vehicle in front of the first gap in the inner lane after the vehicle in the outermost lane of the midstream area has made a reaction decision, in m / s.

[0158] When the conditions for changing lanes to the inside are not met, the vehicle will continue to drive in the outermost lane and adopt a deceleration strategy to reduce the vehicle's running speed from v c Down to v d , to avoid conflicts with downstream vehicles. Different types of vehicles have different deceleration processes and required deceleration distances.

[0159] like Fig.17 As shown in the figure, the deceleration process of a manually driven vehicle can be divided into the gap elimination stage, the braking force increase stage, and the uniform deceleration stage. Since the vehicle system of an autonomous driving vehicle can stably and accurately control the actuator to generate braking deceleration after making a deceleration decision, there is no gap elimination stage for an autonomous driving vehicle.

[0160] The expression of the vehicle travel distance during the entire deceleration stage is shown in formula (14).

[0161]

[0162] In formula (14), v c Indicates the vehicle speed at the starting point of the outermost lane of the main line in the middle reaches, m / s, K 1 represents the time for gap elimination, s, and K of the manually driven vehicle in this embodiment 1 The value is 0.05s, and the K of the autonomous driving vehicle 1 The value is 0s, K 2 represents the time of braking force rising, s, K of the manually driven vehicle in this embodiment 2 The value is 0.3s, and the K of the autonomous driving vehicle 2 The value is 0.4s.

[0163] Based on the above embodiment, the lane-changing distance of the midstream merging safety sight distance or the deceleration distance of the midstream merging safety sight distance in step S3 is expressed as shown in formula (14).

[0164]

[0165] In formula (15), L 6 Indicates the lane-changing distance for the midstream merging safety sight distance or the deceleration distance for the midstream merging safety sight distance, m, S TF Indicates the safe lane-changing distance between the lane-changing vehicle and the vehicle in front of the target lane, m, L car represents the vehicle body length, m, τ represents the execution time of the vehicle lane change, s, v c Indicates the vehicle speed at the starting point of the outermost lane of the main line in the middle section, m / s, Indicates the running speed of the vehicle in the outermost lane of the midstream area after the reaction decision of the vehicle in the first gap of the inner lane, m / s, K 1 represents the time for gap elimination, s, and K of the manually driven vehicle in this embodiment 1 The value is 0.05s, and the K of the autonomous driving vehicle 1 The value is 0s, K 2 represents the time of braking force rising, s, K of the manually driven vehicle in this embodiment 2 The value is 0.3s, and the K of the autonomous driving vehicle 2 The value is 0.4s;

[0166] Based on the above embodiment, the distance expression of the safe sight distance for merging in the midstream area in step S3 is shown in formula (16).

[0167] L H =L 4 +L 5 +L 6 (16)

[0168] In formula (16), L H Indicates the safe sight distance for merging in the midstream area, m, L 4 Represents the reaction distance of the safe sight distance of the merging in the midstream area, m, L 5 Indicates the decision distance of the safe sight distance for merging in the midstream area, m, L 6 It indicates the lane-changing distance for the safe sight distance for merging in the midstream area or the deceleration distance for the safe sight distance for merging in the midstream area, in m.

[0169] Depending on the decision, L 6 The value of is also different, and the value expression is shown in formula (17).

[0170]

[0171] In formula (17), L 6，换道 The distance required for the vehicle to decide to change lanes inward, m; L 6，减速 The distance required for the vehicle to decide to slow down, m.

[0172] Example 2

[0173] like Fig.18 As shown, an embodiment of the present invention provides a continuous inlet spacing calculation model, including:

[0174] Python programming is used to design a solution algorithm for the calculation of continuous entrance spacing based on Monte Carlo simulation. The algorithm uses the Monte Carlo method to simulate the randomness of traffic flow and designs the continuous entrance spacing by determining the length of the appropriate percentile.

[0175] According to the target reliability of the highway pavement structure, the reliability probability is selected as 95%. In this embodiment, the preset length of the upstream acceleration lane gap determination section is 500m, the reliable length under the current preset length is determined, and then iterative calculation is performed until the relative error between the reliable length under the condition that the preset length of the upstream acceleration lane gap determination section is 500m and the preset length of the upstream acceleration lane gap determination section is controlled within a certain range λ, at which time the length of the upstream acceleration lane gap determination section is the average of the reliable length under the condition that the preset length of the upstream acceleration lane gap determination section is 500m and the preset length of the upstream acceleration lane gap determination section; according to the relevant research on the length calculation method of the parallel acceleration lane of the urban expressway, λ is taken as 0.01.

[0176] In this embodiment, the section from Xiaochang District to Xiaonan District of Beijing-Hong Kong-Macao Expressway (G4) is taken as an example. In order to obtain the basic traffic flow data required for the simulation, the traffic volume data of this section during the Spring Festival travel period for three consecutive years is counted, and the average annual traffic volume is used as the number of simulations, as shown in Table 2.

[0177] Table 2 Traffic volume from Xiaochang District to Xiaonan District during the Spring Festival travel season from 2019 to 2021

[0178]

[0179] As shown in Table 2, the total traffic volume of the expressway from 2019 to 2021 is 2.08 million times, and the average of the total traffic volume in three years is about 700,000 times. Therefore, this embodiment uses the average of the total traffic volume in three years of 700,000 as the simulation number Y for Monte Carlo simulation calculation.

[0180] In the process of calculating the length of the acceleration section of the acceleration lane in the upstream area, according to the data analysis results of the trajectory extraction software, in this embodiment, the acceleration value when the vehicle running speed is 0 is ζ = 4.4871, and the rate of change of acceleration to vehicle running speed is η = 0.2359. According to the proportion of different types of drivers, the probability of anxious drivers in the traffic flow is w 1 =0.2, the probability of a general driver is w 2 =0.6, the probability of conservative drivers is w 3 = 0.2. The distribution of parameters involved in the continuous inlet spacing calculation model is shown in Table 3.

[0181] Table 3 Random parameter distribution diagram

[0182]

[0183] According to the determined model parameters, the calculated values ​​of different components are obtained. Among them, the calculated result of the acceleration section length is 33.79m; according to the provisions of the "Highway Grade Separation Design Regulations" (JTG / TD21-2014), when the main line design vehicle running speed is 100km / h, the value of the parallel acceleration lane gradient section length is 80m.

[0184] For the remaining parts of the spacing, as the penetration rate of autonomous vehicles increases, the calculation results decrease accordingly. The reduction in the gap determination segment and the lane change or deceleration distance is relatively uniform. The reaction distance and decision distance decrease relatively uniformly when the penetration rate of autonomous vehicles changes from 0 to 80%, and decrease more significantly when the penetration rate of autonomous vehicles changes from 80% to 100%.

[0185] In this embodiment, by calculating and analyzing the continuous entrance sections with a main line of two lanes, a main line design vehicle operating speed of 100 km / h, and a ramp design vehicle operating speed of 40 km / h, the recommended values ​​of the continuous entrance spacing under different penetration rates of autonomous driving vehicles are shown in Table 4.

[0186] Table 4 Calculation results of continuous entrance spacing

[0187]

[0188] It can be seen from Table 4 that the greater the penetration rate of autonomous driving vehicles, the smaller the recommended value of the continuous entrance spacing, which means that the mixing of autonomous driving vehicles can effectively meet the various driving behavior requirements of vehicles in the continuous entrance section and save road resources.

[0189] Example 3

[0190] like Fig.19 As shown, an embodiment of the present invention provides a system for determining the distance between consecutive entrances of a main line of a highway under heterogeneous traffic flow, the system comprising:

[0191] A traffic flow data acquisition module, used to acquire traffic flow data in a heterogeneous traffic flow environment, analyze vehicle driving behavior based on the traffic flow data, and classify vehicle types into manually driven vehicles and autonomous driving vehicles;

[0192] A lane-changing behavior model building module is used to divide lane-changing scenarios according to the vehicle type of the lane-changing vehicle and the vehicle type of the vehicle behind the lane-changing target lane, analyze the lane-changing decision process based on the lane-changing scenario, divide the lane-changing decision process into position judgment, gap judgment, initial decision of the lane-changing vehicle, decision of the vehicle behind the lane-changing target lane and re-decision of the lane-changing vehicle, and build a lane-changing behavior model corresponding to the lane-changing scenario based on the lane-changing decision process;

[0193] The spacing calculation model construction module is used to calculate the length of the acceleration section of the upstream acceleration lane based on the vehicle acceleration and the vehicle merging speed, calculate the length of the gap determination section of the upstream acceleration lane based on the gap waiting distance and the gap adjustment distance, determine the length of the gradient section of the upstream acceleration lane based on the preset standard, and add the length of the acceleration section of the upstream acceleration lane, the length of the gap determination section of the upstream acceleration lane and the length of the gradient section of the upstream acceleration lane to obtain the length of the upstream acceleration lane; calculate the reaction time of the midstream merging safe sight distance based on the vehicle running speed and the vehicle reaction time Distance, calculate the decision distance of the merging safety sight distance in the midstream area based on the vehicle running speed and the vehicle decision time, calculate the lane changing distance of the merging safety sight distance in the midstream area or the deceleration distance of the merging safety sight distance in the midstream area based on the lane changing decision, add the reaction distance of the merging safety sight distance in the midstream area, the decision distance of the merging safety sight distance in the midstream area and the lane changing distance of the merging safety sight distance in the midstream area or the deceleration distance of the merging safety sight distance in the midstream area to obtain the distance of the merging safety sight distance in the midstream area; add the length of the acceleration lane in the upstream area and the distance of the merging safety sight distance in the midstream area to obtain the spacing of consecutive entrances.

[0194] Example 3

[0195] The present embodiment discloses a computer program product, such as a computer program instruction, which, when executed by a computer, can be called or provided through the operation of the computer according to the method and / or technical solution of the present invention. It should be understood by those skilled in the art that the existence form of the computer program instruction in the computer-readable medium includes but is not limited to source files, executable files, installation package files, etc., and accordingly, the way in which the computer program instruction is executed by the computer includes but is not limited to: the computer directly executes the instruction, or the computer compiles the instruction and then executes the corresponding compiled program, or the computer reads and executes the instruction, or the computer reads and installs the instruction and then executes the corresponding installed program. Here, the computer-readable medium can be any available computer-readable storage medium or communication medium accessible to the computer. It can be clearly understood by those skilled in the art that for the convenience and simplicity of description, the specific working process of the program and module described above can refer to the corresponding process description in the aforementioned method embodiment, and will not be repeated here.

[0196] The algorithm and display provided herein are not inherently related to any particular computer, virtual system or other device. Various general purpose systems can also be used together with the teachings based on this. According to the above description, it is obvious that the structure required for constructing such systems. In addition, the present invention is not directed to any specific programming language either. It should be understood that various programming languages ​​can be utilized to realize the content of the present invention described herein, and the description of the above specific languages ​​is for disclosing the best mode of the present invention.

[0197] In the description provided herein, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0198] Similarly, it should be understood that in order to streamline the present disclosure and aid in understanding one or more of the various inventive aspects, in the above description of exemplary embodiments of the present invention, various features of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. However, this disclosed method should not be interpreted as reflecting the intention that the claimed invention requires more features than those expressly recited in each claim. Rather, as reflected in the claims, inventive aspects lie in less than all of the features of the individual embodiments previously disclosed. Therefore, the claims that follow the detailed description are hereby expressly incorporated into the detailed description, with each claim itself serving as a separate embodiment of the present invention.

Claims

1. A method for determining the distance between consecutive entrances of a highway main line under heterogeneous traffic flow, characterized in that: The following steps are involved: Step S1: acquiring traffic flow data in a heterogeneous traffic flow environment, analyzing vehicle driving behaviors based on the traffic flow data, and classifying vehicle types into manually driven vehicles and autonomous driving vehicles; Step S2: dividing the lane changing scenarios according to the vehicle type of the lane changing vehicle and the vehicle type of the vehicle behind the lane changing target, determining the lane changing scenarios according to the penetration rate of the autonomous driving vehicles, analyzing the lane changing decision process based on the lane changing scenarios, dividing the lane changing decision process into position judgment, gap judgment, initial decision of the lane changing vehicle, decision of the vehicle behind the lane changing target lane and re-decision of the lane changing vehicle, and constructing a lane changing behavior model corresponding to the lane changing scenario based on the lane changing decision process; Step S3: calculating the length of the acceleration section of the upstream acceleration lane based on the vehicle acceleration and the vehicle merging speed, calculating the length of the gap determination section of the upstream acceleration lane based on the gap waiting distance and the gap adjustment distance, determining the length of the gradient section of the upstream acceleration lane based on a preset standard, and adding the length of the acceleration section of the upstream acceleration lane, the length of the gap determination section of the upstream acceleration lane, and the length of the gradient section of the upstream acceleration lane to obtain the length of the upstream acceleration lane; Calculate the reaction distance of the merging safe sight distance in the midstream area based on the vehicle running speed and the vehicle reaction time, calculate the decision distance of the merging safe sight distance in the midstream area based on the vehicle running speed and the vehicle decision time, calculate the lane changing distance of the merging safe sight distance in the midstream area or the deceleration distance of the merging safe sight distance in the midstream area based on the lane changing decision, add the reaction distance of the merging safe sight distance in the midstream area, the decision distance of the merging safe sight distance in the midstream area and the lane changing distance of the merging safe sight distance in the midstream area or the deceleration distance of the merging safe sight distance in the midstream area to obtain the distance of the merging safe sight distance in the midstream area; add the length of the acceleration lane in the upstream area and the distance of the merging safe sight distance in the midstream area to obtain the spacing of consecutive entrances.

2. The method for determining the distance between consecutive entrances of a main line of a highway under heterogeneous traffic flow according to claim 1 is characterized in that: The method for obtaining traffic flow data in a heterogeneous traffic flow environment in step S1 includes: using a drone to take aerial photos at fixed time intervals to collect video data of continuous entrance sections of the main line of the expressway, extracting trajectory data of each vehicle in the video data of the continuous entrance sections of the main line of the expressway through trajectory extraction software, setting different lane areas for the video data of the continuous entrance sections of the main line of the expressway, and obtaining traffic flow data in a heterogeneous traffic flow environment.

3. The method for determining the distance between consecutive entrances of a main line of a highway under heterogeneous traffic flow according to claim 2 is characterized in that: Different lane areas are set for the video data of the continuous entrance sections of the main line of the expressway, including: the main line inner lane, the main line outer lane, the upstream acceleration lane and the downstream acceleration lane.

4. The method for determining the distance between consecutive entrances of a main line of a highway under heterogeneous traffic flow according to claim 1 is characterized in that: In step S2, the lane changing scenarios are divided according to the vehicle type of the lane changing vehicle and the vehicle type of the vehicle behind the lane changing target lane. The lane changing scenarios include: The first lane-changing scenario: Both the vehicle type of the lane-changing vehicle and the vehicle type of the target lane behind are autonomous vehicles; The second lane-changing scenario: the vehicle type of the lane-changing vehicle is an autonomous vehicle, and the vehicle type of the target lane is a manually driven vehicle; The third lane-changing scenario: the vehicle type of the lane-changing vehicle is a manually driven vehicle, and the vehicle type of the vehicle behind the target lane is an autonomous driving vehicle; The fourth lane-changing scenario: the vehicle type of the lane-changing vehicle and the vehicle type of the vehicle behind the lane-changing target are both manually driven vehicles; In step S2, the lane change scenario is determined according to the penetration rate of the autonomous driving vehicle, wherein the expression of the penetration rate of the autonomous driving vehicle is: Among them, p1 represents the penetration rate of autonomous vehicles in the lane where the lane-changing vehicle is located before the lane-changing vehicle changes lanes, and p2 represents the penetration rate of autonomous vehicles in the lane where the lane-changing vehicle is located after the lane-changing vehicle changes lanes. represents the traffic volume of the autonomous driving vehicle in the lane where the lane-changing vehicle was before changing lanes, It represents the traffic volume of the autonomous driving vehicle in the lane where the lane-changing vehicle is located after changing lanes, Q1 represents the total traffic volume in the lane where the lane-changing vehicle is located before changing lanes, and Q2 represents the total traffic volume in the lane where the lane-changing vehicle is located after changing lanes.

5. The method for determining the distance between consecutive entrances of a main line of a highway under heterogeneous traffic flow according to claim 1 is characterized in that: The lane changing decision process based on the lane changing scenario analysis in step S2 includes: calculating the acceptable gaps of the manually driven vehicle and the autonomous driving vehicle respectively based on the acceptable gap model; dividing the lane changing modes into direct lane changing, assisted lane changing and aggressive lane changing according to the difference in the degree of interaction between the manually driven vehicle and the autonomous driving vehicle; and dividing the lane changing intention of the lane changing vehicle into mandatory lane changing intention and arbitrary lane changing intention according to the lane position of the vehicle in the continuous entrance section and the traffic environment.

6. The method for determining the distance between consecutive entrances of a main line of a highway under heterogeneous traffic flow according to claim 2 is characterized in that: The expression of the acceptable gap model is: Among them, G 人 (x) represents the acceptable gap for manually driven vehicles, G 自 (x) represents the acceptable gap of the autonomous vehicle, S max represents the critical acceptable gap required for direct lane change, S min represents the critical acceptable gap required for aggressive lane change, x represents the lane position of the lane-changing vehicle in the continuous entrance segment, x1 represents the starting point of the merging segment, x2 represents the starting point of the gradient segment, x3 represents the end point of the merging segment, and x4 represents the end point of the midstream area.

7. The method for determining the distance between consecutive entrances of a main line of a highway under heterogeneous traffic flow according to claim 1 is characterized in that: The expression for the length of the acceleration section of the upstream acceleration lane in step S3 is: Where L1 represents the length of the acceleration section of the upstream acceleration lane, v represents the vehicle speed, η represents the rate of change of acceleration to vehicle speed, and v b Indicates the vehicle speed when merging, v a represents the vehicle running speed at the merging nose in the upstream area, ζ represents the acceleration when the vehicle running speed is 0; In step S3, the length of the gap determination section of the upstream acceleration lane is divided into a gap waiting distance and a gap adjustment distance; wherein, the expression of the gap waiting distance is: Among them, l wait Indicates the gap waiting distance, Indicates the size of the nth gap in the outermost lane of the main line, L car Indicates the length of the vehicle body, v b Indicates the vehicle speed when the vehicle in the acceleration lane merges. Indicates the running speed of the vehicle in front of the nth gap in the outermost lane of the main line; The gap adjustment distance expression is: Among them, l adjust Indicates the gap adjustment distance, S TF Indicates the safe distance that the vehicle in the acceleration lane should maintain with the vehicle ahead in the gap, L car Indicates the length of the vehicle body. represents the running speed of the vehicle in front of the nth gap in the outermost lane of the main line, v b Indicates the vehicle running speed when the vehicle in the acceleration lane performs merging; The length expression of the upstream acceleration lane gap determination section is: L2＝l wait +l adjust ； Where L2 represents the length of the upstream acceleration lane clearance determination segment, l wait Indicates the gap waiting distance, l adjust Indicates the gap adjustment distance; The expression for the length of the upstream acceleration lane in step S3 is: <h2 style=";text-align:left;direction:ltr">L<h2 style=";text-align:left;direction:ltr"> J <h2 style=";text-align:left;direction:ltr"> (L1+L2+L3) Among them, L J It represents the length of the acceleration lane in the upstream area, L1 represents the length of the acceleration section of the acceleration lane in the upstream area, L2 represents the length of the gap determination section of the acceleration lane in the upstream area, and L3 represents the length of the gradual change section of the acceleration lane in the upstream area.

8. The method for determining the distance between consecutive entrances of a main line of a highway under heterogeneous traffic flow according to claim 1 is characterized in that: The reaction distance expression of the safe sight distance for merging in the midstream area in step S3 is: L4=v c t r ; Among them, L4 represents the reaction distance of the safe sight distance of merging in the midstream area, v c Indicates the vehicle speed at the starting point of the outermost lane of the main line in the midstream area, t r Indicates vehicle reaction time; The decision distance expression of the safe sight distance for merging in the midstream area in step S3 is: L5=v c t d ; Among them, L5 represents the decision distance of the safe sight distance of merging in the midstream area, v c Indicates the vehicle speed at the starting point of the outermost lane of the main line in the midstream area, t d represents the vehicle decision time; The lane-changing distance of the midstream merging safety sight distance or the deceleration distance of the midstream merging safety sight distance in step S3 is expressed as: Wherein, L6 represents the lane-changing distance for the midstream merging safety sight distance or the deceleration distance for the midstream merging safety sight distance, S TF Indicates the safe lane-changing distance between the lane-changing vehicle and the vehicle in front of the target lane, L car represents the vehicle body length, τ represents the execution time of the vehicle lane change, v c Indicates the vehicle speed at the starting point of the outermost lane of the main line in the midstream area. It indicates the running speed of the vehicle in front of the first gap in the inner lane after the vehicle in the outermost lane of the midstream area makes a reaction decision. K1 indicates the time for the gap to be eliminated, and K2 indicates the time for the braking force to increase. The distance expression of the safe sight distance for merging in the midstream area in step S3 is: <h2 style=";text-align:left;direction:ltr">L<h2 style=";text-align:left;direction:ltr"> H <h2 style=";text-align:left;direction:ltr"> (L4+L5+L6) Among them, L H It represents the distance of the merging safety sight distance in the midstream area, L4 represents the reaction distance of the merging safety sight distance in the midstream area, L5 represents the decision distance of the merging safety sight distance in the midstream area, and L6 represents the lane changing distance of the merging safety sight distance in the midstream area or the deceleration distance of the merging safety sight distance in the midstream area.

9. A system for determining the distance between consecutive entrances of a highway main line under heterogeneous traffic flow, characterized in that: include: A traffic flow data acquisition module, used to acquire traffic flow data in a heterogeneous traffic flow environment, analyze vehicle driving behavior based on the traffic flow data, and classify vehicle types into manually driven vehicles and autonomous driving vehicles; A lane-changing behavior model construction module is used to divide lane-changing scenarios according to the vehicle type of the lane-changing vehicle and the vehicle type of the vehicle behind the lane-changing target lane, determine the lane-changing scenario according to the penetration rate of the autonomous driving vehicle, analyze the lane-changing decision process based on the lane-changing scenario, divide the lane-changing decision process into position judgment, gap judgment, initial decision of the lane-changing vehicle, decision of the vehicle behind the lane-changing target lane and re-decision of the lane-changing vehicle, and construct a lane-changing behavior model corresponding to the lane-changing scenario based on the lane-changing decision process; a spacing calculation model building module, for calculating the length of the acceleration section of the upstream acceleration lane based on the vehicle acceleration and the vehicle merging speed, calculating the length of the gap determination section of the upstream acceleration lane based on the gap waiting distance and the gap adjustment distance, determining the length of the gradient section of the upstream acceleration lane based on a preset standard, and adding the length of the acceleration section of the upstream acceleration lane, the length of the gap determination section of the upstream acceleration lane, and the length of the gradient section of the upstream acceleration lane to obtain the length of the upstream acceleration lane; Calculate the reaction distance of the merging safe sight distance in the midstream area based on the vehicle running speed and the vehicle reaction time, calculate the decision distance of the merging safe sight distance in the midstream area based on the vehicle running speed and the vehicle decision time, calculate the lane changing distance of the merging safe sight distance in the midstream area or the deceleration distance of the merging safe sight distance in the midstream area based on the lane changing decision, add the reaction distance of the merging safe sight distance in the midstream area, the decision distance of the merging safe sight distance in the midstream area and the lane changing distance of the merging safe sight distance in the midstream area or the deceleration distance of the merging safe sight distance in the midstream area to obtain the distance of the merging safe sight distance in the midstream area; add the length of the acceleration lane in the upstream area and the distance of the merging safe sight distance in the midstream area to obtain the spacing of consecutive entrances.

10. A computer program product, characterized in that The method comprises computer instructions, wherein the computer instructions are used to make a computer execute the method for determining the continuous entrance spacing of a main line of a highway under heterogeneous traffic flow in claim 1.

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