Method for calculating road intersection entrance direction saturation and electronic device

Abstract

The application provides a method for calculating saturation of road intersection import direction, comprising: obtaining real-time vehicle quantity and vehicle speed of each import lane stop line position of road intersection; obtaining corresponding signal light color of each import lane of road intersection; establishing vehicle speed record list corresponding to current signal period, counting total vehicle quantity, and recording green light duration and yellow light duration; calculating average vehicle speed of import lane vehicle of road intersection, and comparing with maximum historical average vehicle speed; calculating import lane saturation flow of road intersection; calculating traffic flow of import lane of road intersection; and calculating saturation of road intersection import direction. The application can realize real-time, accurate and automatic calculation of import lane saturation value through vehicle detector, traffic signal control machine and other devices.

Description

Technical Field

[0001] This invention belongs to the field of urban road traffic management technology, specifically relating to a method and electronic device for calculating the saturation of the approach direction of a road intersection. Background Technology

[0002] Traffic congestion is a major problem faced by large and medium-sized cities in modern society. The congestion in many cities is becoming increasingly severe and complex, resulting not only in significant socio-economic losses and inefficient travel, but also posing a significant threat to traffic safety and environmental protection. Urban road intersections are the choke points of the urban road network, serving as convergence points for pedestrian, non-motorized, and motorized traffic. Interference and intersections between these flows reduce vehicle speed and easily lead to congestion. Improving traffic congestion at oversaturated urban road intersections through signal timing and traffic organization optimization design is one of the important tasks for traffic engineers both domestically and internationally.

[0003] Saturation refers to the ratio of actual traffic volume to the capacity of an approach lane. It is an indicator describing the traffic load of a road or intersection and reflects the level of service of the intersection. When implementing road traffic signal control, it is necessary to determine the control method and timing parameters of the intersection based on the saturation of each approach direction. The parameters required for saturation calculation include actual traffic volume and approach lane capacity. The factors affecting the approach lane capacity include: (1) intersection road conditions; (2) intersection traffic environment; (3) signal timing. Conventional methods for calculating saturation values ​​require complex parameters that are difficult to obtain directly through sensors. Therefore, in practical engineering applications, the "approach lane capacity" required for calculating saturation is usually set manually based on experience and then calculated in combination with traffic flow data. The accuracy of the calculated saturation depends to a large extent on human experience. Summary of the Invention

[0004] This invention provides a method for calculating the saturation of the approach direction at a road intersection. By interfacing with communication interfaces of devices such as vehicle detectors and traffic signal controllers, it enables real-time and accurate automatic calculation of the saturation value of the approach lanes. This solves the problem in existing technologies where saturation calculations require complex parameters that are difficult to obtain directly through sensors. Furthermore, this invention also provides an electronic device for implementing the above method.

[0005] This invention discloses a method for calculating the saturation of the approach direction of a road intersection, which mainly includes the following steps:

[0006] Obtain the real-time number of vehicles passing through and their speed at the stop line positions of each approach lane at a road intersection;

[0007] Obtain the color of the traffic lights corresponding to each approach lane at a road intersection;

[0008] Establish a vehicle speed record list corresponding to the current signal cycle. The vehicle speed record list includes the vehicle speed of the vehicle passing through the stop line of the road intersection entrance lane during the effective green light period of the current signal cycle corresponding to the signal light color of the entrance lane. Count the total number of vehicles passing through the stop line of the road intersection entrance lane during the effective green light period of the current signal cycle, and record the green light duration and yellow light duration of each entrance lane of the road intersection during the current signal cycle.

[0009] The average speed of vehicles entering the road intersection lane is calculated based on the vehicle speed record list and compared with the historical average speed maximum value. If the current calculated value is greater than the historical maximum value, the current calculated value is taken as the historical average speed maximum value.

[0010] Calculate the saturation flow rate S of the approach lanes at the road intersection based on the historical maximum average vehicle speed. i ;

[0011] Based on the vehicle speed record list, calculate the traffic flow q at the entrance lane of the road intersection. i ;

[0012] Based on the saturated flow rate S of the approach lanes at the road intersection i Traffic flow q at the intersection entrance lane i Calculate the saturation X in the direction of the road intersection entrance.

[0013] Furthermore, the average speed of vehicles in the approach lanes of the road intersection is calculated, specifically including:

[0014] Filter invalid samples from the vehicle speed record list, including vehicle speeds v. i Samples with speeds 30% lower than the design speed and 10% higher than the design speed;

[0015] Accumulate the filtered valid samples and calculate the average vehicle speed of vehicles in each approach lane of the road intersection.

[0016] The average vehicle speed is compared with the historical maximum average vehicle speed. If the average vehicle speed is greater than the historical maximum average vehicle speed, then the average vehicle speed is taken as the historical maximum average vehicle speed. If it is less than the historical average vehicle speed maximum value Remain unchanged;

[0017]

[0018] In the formula, This represents the average vehicle speed during the valid green light period at the stop line position of the i-th approach lane, where the valid green light period includes both the green light period and the yellow light period; vi The value m represents the speed at which valid sample vehicles pass the stop line; m represents the number of valid samples.

[0019] Furthermore, calculate the saturated flow rate S of the approach lanes at the road intersection. i Specifically, it includes:

[0020]

[0021] In the formula, S i represents the saturation flow of the i-th inlet lane; l represents the average headway of free-flowing vehicles at the intersection.

[0022] Furthermore, the empirical value of l is 15 to 20 m.

[0023] Furthermore, calculate the traffic flow q at the approach lanes of the road intersection. i Specifically, it includes:

[0024]

[0025] In the formula, q i q represents the traffic flow at the i-th approach lane; Ge，i t represents the total number of vehicles that passed the stop line during a valid green light period for the signal light corresponding to the i-th approach lane; G，i t represents the green light duration for the i-th import lane; Y，i This indicates the duration of the yellow light corresponding to the i-th import lane.

[0026] Furthermore, the feature is that the real-time number of passing vehicles and the passing speed are obtained through vehicle detectors.

[0027] Furthermore, the vehicle detector includes a radar vehicle detector and a video vehicle detector.

[0028] Furthermore, the color of the traffic light is obtained through a traffic signal controller or a traffic light drive circuit.

[0029] The present invention also discloses an electronic device, including a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer program, implements the method described above for calculating the saturation of the approach direction of a road intersection.

[0030] The present invention has the following beneficial effects:

[0031] This invention only requires detecting the speed of vehicles crossing the stop line during green and yellow light periods to calculate the saturation level of the road intersection's approach direction. Vehicle speed is one of the basic detection data points for various vehicle detectors, making it convenient, accurate, and easily obtainable in engineering applications. Furthermore, traffic light colors can be directly received from the traffic signal controller's communication data or obtained by sampling from the traffic lights through the traffic light drive circuit, making implementation convenient in engineering. Therefore, this invention enables real-time and accurate automatic calculation of saturation, thus providing a direct reflection of the service level of the road intersection. Moreover, this invention can be applied to traffic signal optimization evaluation systems, providing data support for adaptive optimization control of road intersections. Attached Figure Description

[0032] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0033] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0034] Combination Figure 1 As shown, this invention provides a method for calculating the saturation of the approach direction of a road intersection, mainly including the following steps:

[0035] Step 1: The edge computing device or central software receives data sent by the vehicle detector through the communication interface and obtains the traffic parameters needed for saturation calculation.

[0036] Among them, vehicle detectors can be common radar vehicle detectors, video vehicle detectors, etc.

[0037] The traffic parameters mainly include the real-time number of vehicles passing through each approach lane of the road intersection (hereinafter referred to as the approach lane) and the passing speed. Specifically, the real-time number of vehicles passing through the approach lane of the road intersection refers to the real-time number of vehicles passing through the stop line position of each approach lane of the road intersection; the passing speed refers to the vehicle passing speed at the stop line position of each approach lane of the road intersection.

[0038] Step 2: The edge computing device or central software receives data sent by the traffic signal controller (hereinafter referred to as the signal controller) through the communication interface and obtains the corresponding signal light colors for each approach lane of the road intersection.

[0039] Optionally, in actual use, if the signal controller does not have this function, the color of the signal light can be sampled directly through the signal light drive circuit.

[0040] Step 3: Establish a vehicle speed record list V corresponding to the current signal cycle, including the vehicle speed v of the approach lane corresponding to the current signal cycle when the traffic light color is valid during the green light period (i.e., green light + yellow light) and the vehicle passes the stop line of the approach lane at the road intersection. i; Count the total number of vehicles passing the stop line at the entrance lane of the road intersection during the valid green light period of the current signal cycle, q Ge，i Simultaneously record the green light duration t corresponding to the approach lane within the current signal cycle. G，i Yellow light duration t Y，i The signal cycle here refers to the time required for the traffic light colors at a road intersection to change once according to the set traffic signal release sequence. Note that recording should stop when the traffic light turns red.

[0041] For example, the list of vehicle speed records corresponding to the current cycle is V = {v1, v2, ..., v...} i , ..., v n}, v i Let be the speed of the i-th vehicle when the current signal cycle stops collecting data, and n be the sequence number of the last vehicle when the current signal cycle stops collecting data.

[0042] Step 4: Calculate the average speed of vehicles in the approach lanes of the road intersection in the vehicle speed record list V. The calculation method specifically includes sub-steps:

[0043] 41. Filtering invalid samples: The vehicle speed v collected in step 3 i Data filtering is required to remove interfering data. Specifically, first, each sample value in the vehicle speed record list is compared with the road's design speed; samples with speeds 30% lower than the design speed are discarded. Then, the remaining sample values ​​in the vehicle speed record list are compared with the road's design speed; samples with speeds 10% higher than the design speed are discarded. For example, on a secondary arterial road with a design speed of 40 km / h, samples with speeds exceeding 52 km / h and speeds below 28 km / h should be discarded.

[0044] 42. Calculate the average vehicle speed: Accumulate the filtered valid samples and calculate the average vehicle speed.

[0045]

[0046] In the formula, The average speed during the valid green light period at the stop line position of the i-th approach lane is expressed in m / s; v i The speed of valid sample vehicles passing the stop line is expressed in m / s; m represents the number of valid samples.

[0047] 43. Data Iteration: Compare the calculated average vehicle speed with the historical maximum average vehicle speed. If the calculated value is greater than the historical maximum, then the calculated value is taken as the historical maximum average vehicle speed. If it is less than the historical average vehicle speed maximum value It remains unchanged.

[0048] Step 5: Calculate the saturation flow rate S of the approach lanes at the road intersection. i (vehicles / hour), calculated as follows:

[0049]

[0050] In the formula, S i The saturation flow rate of the i-th approach lane is expressed in vehicles per hour; l represents the average headway of free-flowing vehicles at the intersection in meters. An empirical value for l is 15–20 meters, for example, 15 meters can be used, but it can also be revised according to actual conditions. This represents the maximum historical average vehicle speed of the i-th approach lane, in m / s, calculated in step 4. Here, "free-flow at the intersection" refers to a situation where vehicles on the road move freely under conditions of very low traffic volume.

[0051] Step 6: Calculate the traffic flow q at the approach lanes of the road intersection. i (vehicles / hour), calculated as follows:

[0052]

[0053] In the formula, q i q represents the traffic flow (vehicles / hour) of the i-th approach lane; Ge，i This represents the total number of vehicles that passed the stop line during the valid green light period corresponding to the i-th approach lane, obtained in step 3; t G，i This represents the green light duration corresponding to the i-th import lane, obtained in step 3; t Y，i This represents the duration of the yellow light corresponding to the i-th import lane, obtained in step 3.

[0054] Step 7: Calculate the saturation X (floating-point number) at the road intersection entrance direction, as follows:

[0055]

[0056] In the formula, X represents the saturation degree of the approach lane; q i S represents the traffic flow (vehicles / hour) of the i-th approach lane at the intersection, calculated in step 6, which is also the actual traffic volume of the approach lane; i This represents the saturation flow rate (vehicles / hour) of the i-th approach lane, calculated in step 5, which is also the capacity of the approach lane.

[0057] This allows us to obtain the saturation level at the entrance of the road intersection.

[0058] The embodiments also disclose an electronic device, including a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the method for calculating the saturation of the approach direction of a road intersection as described in the above embodiments, which will not be repeated here.

[0059] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method of calculating the saturation of an approach direction to a road intersection, characterized by, The method comprises the following steps: acquiring real-time vehicle passing quantity and vehicle passing speed of each approach lane stop line position of a road intersection; acquiring corresponding signal light color of each approach lane of the road intersection; establishing a vehicle passing speed record list corresponding to a current signal cycle, the vehicle passing speed record list comprising vehicle passing speed of a vehicle passing the approach lane stop line of the road intersection during effective green light period of the current signal cycle corresponding signal light color of the approach lane; counting total vehicle passing quantity of the approach lane stop line of the road intersection during the effective green light period of the current signal cycle, and recording green light duration and yellow light duration of each approach lane of the road intersection during the current signal cycle; the effective green light period comprising the green light period and the yellow light period; calculating average vehicle speed of the approach lane of the road intersection based on the vehicle passing speed record list, and comparing the average vehicle speed with a historical maximum average vehicle speed, if the current calculation value is greater than the historical maximum average vehicle speed, then taking the current calculation value as the historical maximum average vehicle speed; Based on the historical average vehicle speed maximum value to calculate the road intersection entrance lane saturation flow S i ; calculating a traffic flow q for an approach lane of a road intersection based on the list of passed vehicle speeds i ; based on the road intersection approach lane saturation flow S i and the road intersection approach lane traffic flow q i calculating a road intersection approach direction saturation X, 2. The method of claim 1, wherein, calculating average vehicle speed of the approach lane of the road intersection, specifically comprising: Filtering out invalid samples in the vehicle speed record list, the invalid samples including overpass speed v i Samples lower than 30% of the design speed and higher than 10% of the design speed Accumulate the filtered valid samples to calculate the average vehicle speed of vehicles in each entrance lane of the road intersection comparing the average vehicle speed with a historical average vehicle speed maximum, and if greater than the historical average vehicle speed maximum, the average vehicle speed is used as the historical average vehicle speed maximum if less than the historical average vehicle speed maximum remains unchanged; In the formula, vi represents the average speed of the ith entrance lane stop line position during the effective green light period, which includes the green light period and the yellow light period; v i vi represents the speed of the effective sample vehicle passing through the stop line; m represents the number of effective samples.

3. The method of claim 2, wherein, Computing road intersection approach lane saturation flow S i , specifically comprising: In the formula, S i represents the saturation flow rate of the ith approach lane; and l represents the average vehicle headway of the intersection free flow.

4. The method of claim 3, wherein, the empirical value of the free flow average vehicle headway l of the road intersection is 15-20m.

5. The method of claim 1, wherein, Computing road intersection approach lane traffic flow q i , specifically comprising: In the formula, q i represents the traffic flow of the ith entrance lane; q Ge,i represents the total number of vehicles passing through the stop line during the effective green light period of the ith entrance lane corresponding signal light; t G,i represents the green light duration of the ith entrance lane corresponding signal light; t Y,i represents the yellow light duration of the ith entrance lane corresponding signal light.

6. The method of claim 1 to 5, wherein, The real-time vehicle passing quantity and vehicle passing speed are acquired by a vehicle detector.

7. The method of claim 6, wherein the calculating of the approach direction saturation of the road intersection is characterized by, The vehicle detector comprises a radar vehicle detector and a video vehicle detector.

8. The method of claim 1 to 5, wherein, The signal light color is acquired by a traffic signal control machine or a signal light driving circuit.

9. An electronic device comprising a processor, a memory, and a computer program stored on the memory and executable on the processor, characterized in that, The processor, when executing the computer program, realizes the method for calculating approach direction saturation of the road intersection according to any one of claims 1-8.

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