A method and device for constructing a variable lane assignment model of a road section

Abstract

The application relates to a road section variable lane allocation model construction method and device, belonging to the technical field of traffic signal control engineering, wherein the road section variable lane allocation model construction method comprises the following steps: a variable lane section switching cell transmission model is constructed to simulate the traffic flow transmission process before and after the variable lane switching of a road section; an arterial road lane allocation evaluation mechanism is established; a target function with the minimum total travel delay of a path as an optimization target is constructed based on the arterial road lane allocation evaluation mechanism; and constraint conditions are set for the target function; and after the optimization of the variable lane section switching cell transmission model based on the target function and the constraint conditions, a road section variable lane allocation model is constructed to determine the variable lane allocation scheme of the road section, so that the arterial traffic flow travel stability is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of traffic signal control, and in particular to a method and device for constructing a variable lane allocation model of a road section. BACKGROUND

[0002] With the rapid development of China's economy, the number of motor vehicles has increased dramatically.

[0003] The tidal congestion problem caused by commuting is still an unsolved urban problem, which seriously restricts the healthy operation and steady development of the urban traffic system. The variable lane technology is an effective measure to alleviate this phenomenon.

[0004] However, in the research of variable lanes, the premise is that all road sections in the road network have adaptive traffic conditions for setting variable lanes, ignoring the spatial distribution characteristics of tidal traffic flow in the road network and the requirements for setting variable lanes. SUMMARY

[0005] Therefore, it is necessary to provide a method and device for constructing a variable lane allocation model of a road section to solve the technical problem that the spatial distribution characteristics of tidal traffic flow in the road network and the requirements for setting variable lanes are not considered when variable lanes are opened.

[0006] To solve the above problems, the present application provides a method for constructing a variable lane allocation model of a road section, comprising:

[0007] A variable lane section switching cell transmission model is constructed to simulate the traffic flow transmission process before and after the variable lane switching of the road section;

[0008] An arterial road lane allocation evaluation mechanism is established, a target function with the minimum total travel delay of the path as the optimization objective is constructed based on the arterial road lane allocation evaluation mechanism, and a constraint condition is set for the target function;

[0009] After the variable lane section switching cell transmission model is optimized based on the target function and the constraint condition, a variable lane allocation model of the road section is constructed to determine the variable lane allocation scheme of the road section.

[0010] In one possible implementation, the method for constructing a variable lane section switching cell transmission model comprises:

[0011] The uplink direction and the downlink direction of the road section are determined, wherein the uplink direction is the heavy traffic flow direction, and the downlink direction is the light traffic flow direction;

[0012] The road section is divided into a plurality of cells to determine the heavy traffic flow direction cells and the light traffic flow direction cells;

[0013] The lane number of the heavy traffic direction cell, the traffic density of the heavy traffic direction cell, the inflow rate of the heavy traffic direction cell, the lane number of the light traffic direction cell, the traffic density of the light traffic direction cell, and the inflow rate of the light traffic direction cell are determined based on the lane number of the heavy traffic direction cell, the traffic density of the heavy traffic direction cell, the inflow rate of the heavy traffic direction cell, the lane number of the light traffic direction cell, the traffic density of the light traffic direction cell, and the inflow rate of the light traffic direction cell, and a cell transmission model of variable lane section switching is constructed based on the lane number of the heavy traffic direction cell, the traffic density of the heavy traffic direction cell, the inflow rate of the heavy traffic direction cell, the lane number of the light traffic direction cell, the traffic density of the light traffic direction cell, and the inflow rate of the light traffic direction cell.

[0014] In a possible implementation, the calculation formula of the lane number of the heavy traffic direction cell is as follows:

[0015]

[0016]

[0017] wherein n k,p,i (t) is the lane number of the heavy traffic direction cell at time t, N k is the length of the road section R k,p is the lane number of the heavy traffic direction cell at the initial time, N k,p is the lane number of the pre-switching, C(t) is the length of the empty road section at time t, C(t+Δt) is the length of the empty road section at a time step after time t, l k,p,i is the length of the road section R k,p is the length of the cell i k,p is the last cell number of the road section R k,p , and Δt is a time step, i is a cell number, t0 is the simulation step length at the time when the tidal lane corridor is opened, and t is a certain time. is the light traffic vehicle driving-off speed.

[0018] In a possible implementation, the calculation formula of the traffic density of the heavy traffic direction cell is as follows:

[0019]

[0020]

[0021] wherein k k,p,i (t) is the traffic density of the heavy traffic direction cell i at time t on the road section R k,p , C(t-Δt) is the length of the empty road section at a time step before time t, n k,p,i (t-Δt) is the lane number of the heavy traffic direction cell i after the variable lane is opened at a time step before time t, k k,p,i (t-Δt) is the length of the road section R k,pthe traffic flow density of the heavy traffic flow direction cell i at the previous time step of time t, l i L is the length of the cell i, q i+1 (t-Δt) is the road section R k,p the inflow rate of the heavy traffic flow direction cell i+1 at time t-Δt, q i (t-Δt) is the road section R k,p the inflow rate of the heavy traffic flow direction cell i at time t-Δt.

[0022] In a possible implementation, the calculation formula of the inflow rate of the heavy traffic flow direction cell is:

[0023]

[0024] wherein q k,p,i (t) is the road section R k,p the inflow rate of the heavy traffic flow direction cell i at time t, S k,p,i-1 (t) is the road section R k,p the sending capacity of the upstream cell i-1 of the heavy traffic flow direction cell i, R k,p,i (t) is the road section R k,p the receiving capacity of the heavy traffic flow direction cell i.

[0025] In a possible implementation, the calculation formula of the number of lanes of the light traffic flow direction cell is:

[0026]

[0027] wherein n′ k,p,i N′ (t) is the number of lanes of the light traffic flow direction cell at time t, N′ k is the road section R k,p the number of lanes of the light traffic flow direction at the initial time, N k,p is the number of lanes of the pre-switch, l k,p,i is the road section R k,p the length of the cell i, i k,p is the road section R k,p the last cell number of the road section R.

[0028] In a possible implementation, the calculation formula of the traffic flow density of the light traffic flow direction cell is:

[0029]

[0030] wherein k′ k,p,i N′ (t) is the road section R k,p the traffic flow density of the light traffic flow direction cell i at time t, n′ k,p,i k′ (t-Δt) is the number of lanes of the light traffic flow direction cell i after the variable lane opening at the previous time step of time t.k,p,i (t-Δt) represents road segment R k,p Traffic flow density in cell i at time t, one time step prior to time t. i Let q' be the length of cell i. i (t-Δt) represents road segment R k,p The inflow rate of cell i in the light traffic flow direction at time t-Δt, q′ i-1 (t-Δt) represents road segment R k,p The inflow rate of cell i-1 in the light traffic flow direction at time t-Δt.

[0031] In one possible implementation, the inflow rate of the light traffic flow direction cell is calculated as follows:

[0032]

[0033] Where, q′ k,p,i (t) represents road segment R k,p The inflow rate of light traffic flow direction cell i at time t, S′ k,p,i+1 (t) represents road segment R k,p The transmission capacity of the upstream cell i+1 of cell i in the light traffic flow direction, R′ k,p,i (t) represents road segment R k,p The receiving capability of cell i in the direction of light traffic flow.

[0034] In one possible implementation, the objective function is calculated as follows:

[0035]

[0036]

[0037] D k,p,i (t)=Δt·(k k,p,i (t)·l k,p,i -q k,p,i+1 (t)·Δt),

[0038]

[0039] Where, minD total Let D be the objective function. k,p,i (t) represents the vehicle delay per unit time in a single cell, D k,p D represents the total travel delay of the p-th segment of arterial road k during the tidal corridor opening period. k,1 Let N be the total travel delay of the first segment of arterial road k during the tidal corridor opening period, f((k,p-1),(k,p)) be the arterial road lane allocation evaluation mechanism, and N be the total travel delay of the first segment of arterial road k during the tidal corridor opening period. k +N k,p For road segment R k,pthe number of heavy traffic flow direction lane assignments, N k + k,p-1 for a road segment R k,p the previous road segment R k,p-1 the number of heavy traffic flow direction lane assignments, t e for a time step when variable lane closure, q k,p,i+1 for a road segment R k,p the inflow rate of the upstream cell i+1 of the heavy traffic flow direction cell i at time t, l k,p,i for a road segment R k,p the length of cell i;

[0040] The constraint conditions at least include the saturation of the heavy traffic flow direction of the arterial road, the average saturation of the heavy traffic flow direction of the arterial road, the saturation of the light traffic flow direction of the arterial road, and the average saturation of the light traffic flow direction of the arterial road, and the calculation formula of the constraint conditions is:

[0041]

[0042]

[0043]

[0044]

[0045] wherein x k (t) is the saturation of the heavy traffic flow direction of the arterial road k at time t, is the average saturation of the heavy traffic flow direction of the arterial road k, q k,p,max for a road segment R k,p the maximum allowed inflow rate of the heavy traffic flow direction cell, x' k (t) is the saturation of the light traffic flow direction of the arterial road k at time t, is the average saturation of the light traffic flow direction of the arterial road k.

[0046] In another aspect, the present application also provides a construction device of a road segment variable lane assignment model, comprising:

[0047] a cell transmission model construction module, configured to construct a cell transmission model of variable lane assignment of a road segment, so as to simulate the traffic flow transmission process before and after the variable lane assignment of the road segment;

[0048] a target function construction module, configured to establish an arterial road lane assignment evaluation mechanism, based on the arterial road lane assignment evaluation mechanism, to construct a target function with the minimum path total travel delay as an optimization target, and to set a constraint condition for the target function;

[0049] The variable lane allocation model establishment module is configured to, after optimizing the cell transmission model of the variable lane section switching based on the target function and the constraint condition, construct a variable lane allocation model of the road section to determine a variable lane allocation scheme of the road section.

[0050] The present application has the advantages that: considering the spatial distribution characteristics of tidal traffic flow in the road network and the requirements of variable lane setting, a cell transmission model of variable lane section switching is constructed, data input conditions for a variable lane allocation model of the road section are provided by simulating the traffic flow transmission process before and after the variable lane switching of the road section, an arterial road lane allocation evaluation mechanism is established to make the lane allocation schemes of the same arterial road on the path consistent, a target function with the minimum total travel delay of the path as the optimization objective is constructed based on the arterial road lane allocation evaluation mechanism, and constraint conditions are set for the target function, the lane allocation of the road section is uniformly allocated by introducing the definition of cell vehicle travel delay and taking the minimum total delay of the path as the objective, the cell transmission model of the variable lane section switching is optimized based on the target function and the constraint condition to establish the variable lane allocation model of the road section, the lane allocation schemes of multiple road sections on the entire path are comprehensively considered to determine the variable lane allocation scheme of the road section, the method is suitable for calculating the delay of the road section in the variable lane dynamic switching scenario, and the stability of the arterial road traffic flow is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0051] Figure 1 An embodiment of the construction method of the variable lane allocation model of the road section provided by the present application is shown in the flowchart.

[0052] Figure 2 A schematic diagram of the cell N emptying in the construction method of the variable lane allocation model of the road section provided by the present application is shown in the flowchart.

[0053] Figure 3 A schematic diagram of the cell N-1 emptying in the construction method of the variable lane allocation model of the road section provided by the present application is shown in the flowchart.

[0054] Figure 4 An embodiment structure schematic diagram of the construction device of the variable lane allocation model of the road section provided by the present application is shown in the flowchart. DETAILED DESCRIPTION

[0055] The preferred embodiments of the present application will be described in detail below with reference to the accompanying drawings, wherein the drawings constitute a part of this application and serve to explain the principles of the embodiments of the present application, but are not used to limit the scope of the present application.

[0056] One specific embodiment of the present application discloses a construction method of a variable lane allocation model of a road section, Figure 1 is a flowchart of the construction method of the variable lane allocation model of the road section provided by the embodiment of the present application, please refer to Figure 1The method for constructing the variable lane allocation model of a road section comprises the following steps:

[0057] In S101, a cell transmission model of variable lane section switching is constructed to simulate the traffic flow transmission process before and after the variable lane switching of the road section.

[0058] In S102, an arterial lane allocation evaluation mechanism is established, a target function with the minimum total travel delay of a path as an optimization objective is constructed based on the arterial lane allocation evaluation mechanism, and a constraint condition is set for the target function.

[0059] In S103, after the cell transmission model of variable lane section switching is optimized based on the target function and the constraint condition, a variable lane allocation model of the road section is constructed to determine the variable lane allocation scheme of the road section.

[0060] Compared with the prior art, the method for constructing the variable lane allocation model of a road section provided in the embodiment has the following advantages: the cell transmission model of variable lane section switching is constructed to simulate the traffic flow transmission process before and after the variable lane switching of the road section; the arterial lane allocation evaluation mechanism is established, the target function with the minimum total travel delay of a path as an optimization objective is constructed based on the arterial lane allocation evaluation mechanism, and the constraint condition is set for the target function; after the cell transmission model of variable lane section switching is optimized based on the target function and the constraint condition, the variable lane allocation model of the road section is established to determine the variable lane allocation scheme of the road section; the cell transmission model of variable lane section switching is used to simulate the traffic flow transmission process before and after the variable lane switching of the road section to provide the data input condition for the variable lane allocation model of the road section; the cell transmission model of variable lane section switching is used to simulate the change of the cell parameters in the variable lane switching process, the variable lane switching is mapped to the change of indexes such as the cell jam density and the saturated flow rate, the vehicle transfer formula and the state transfer formula are updated, the target function with the minimum total travel delay of a path as an optimization objective is constructed, the road section lanes are uniformly allocated with the minimum total travel delay of a path as an objective, the lane allocation scheme of the same arterial road on the path tends to be consistent through the establishment of the arterial lane allocation evaluation mechanism, and the traffic flow stability of the arterial road is ensured.

[0061] In some embodiments, in S101, the lane allocation schemes of multiple road sections on the entire path are comprehensively considered, the spatial distribution characteristics of the tidal traffic flow in the road network and the variable lane setting requirements are considered, the cell transmission model of variable lane section switching is constructed to simulate the traffic flow transmission process before and after the variable lane switching of the road section, and first, some situations of the variable lane setting are described as follows:

[0062] (1) All road sections on the critical path meet the road conditions for variable lane setting: the number of motor vehicle lanes is 4-12; there are no physical isolation facilities such as elevated bridge piers and trolley buses in the road center; if there are simple green isolation or barrier isolation facilities, they can be removed to ensure the road conditions for variable lane implementation.

[0063] (2) The length of the critical path is within 2-5 kilometers to avoid excessive length of variable lane setting on the whole line, which is not conducive to the management of traffic control departments and the driving safety of drivers.

[0064] (3) The setting of variable lanes will not cause a significant change in the overall flow of road sections during the morning peak period in a short period of time.

[0065] Determine the uplink direction and downlink direction of the road section. The uplink direction is the heavy traffic flow direction, and the downlink direction is the light traffic flow direction. Divide the road section into multiple cells to determine heavy traffic flow direction cells and light traffic flow direction cells. Segment the variable lane by cell. At the initial moment, the variable lane travel direction is the light traffic flow direction. Please refer to Figure 2 for the schematic diagram of cell N being emptied, and Figure 3 for the schematic diagram of cell N-1 being emptied. Take Figure 2 and Figure 3 as examples to explain the switching rules of variable lanes. Figure 2 represents that cell N is being emptied, where the emptied road sections are marked green and the non-empty road sections are marked red. To avoid collision danger, it is stipulated that heavy traffic flow vehicles can only change lanes to enter the cell after the cell is completely emptied. During the emptying period, vehicles are prohibited from entering, indicated by the symbol × in the cell N. The vehicles in the remaining cells normally travel in the original directional arrow direction. Figure 3 represents that cell N has been completely emptied, and the directional arrow has changed to the heavy traffic flow direction. Heavy traffic flow vehicles can change lanes to enter cell N, and cell N-1 begins to empty, with vehicle access prohibited. In this way, the reverse emptying is implemented from cell N, and the process continues until cell 1 is completely emptied, which completes the direction switching of the variable lanes on the entire road section.

[0066] The VCTM (Variable Cellular Transfer Model) for road segments is a computer-simulated traffic flow model. This model abstracts the road network as a two-dimensional grid, dividing the road into cells, each representing a fixed-length road segment. By updating and evolving these cells, the model simulates the movement and interaction of vehicles within the road network. Based on the VCTM model, the number of lanes, traffic density, and flow rate of cells in the heavy traffic flow direction are determined. Based on the number of lanes, traffic density, and inflow rate of light traffic flow direction cells, and considering the number of lanes, traffic density, and inflow rate of heavy traffic flow direction cells, as well as the number of lanes, traffic density, and inflow rate of light traffic flow direction cells, a cell transmission model for variable lane segmented switching is constructed. First, the length of the cleared road segment at time t is determined, and the formula for calculating the length of the cleared road segment at time t is:

[0067]

[0068] Where C(t) is the length of the cleared road segment at time t, and C(t+Δt) is the length of the cleared road segment at one time step after time t. The speed at which light traffic flows leave is the average speed of the road segment, t is a certain moment, and t0 is the simulation step size for the moment when the tidal lane corridor is opened.

[0069] The number of lanes in the cell representing the direction of heavy traffic flow is determined by the following formula:

[0070]

[0071] Where, n k,p,i (t) represents the number of lanes in the cell representing the direction of heavy traffic flow at time t, N k For road segment R k,p Number of lanes in the direction of heavy traffic flow at the initial time, N k,p i is the number of lanes to be switched. k,p For road segment R k,p The last cell number, l k,p,i For road segment R k,p The length of the cell, where i is the cell number.

[0072] Variable lane switching directly impacts cell receiving and transmitting capabilities. Based on the road segment VCTM cell transmission model, cell parameters are adjusted during the variable lane switching process. After lane switching, the overall traffic flow of the road segment does not change significantly for a short period. k,pThe single-lane density and single-lane flow of the heavy traffic flow cell i will change instantaneously with the change of the number of lanes at the moment of completing emptying, and since the actual emptying moment of the cell is not necessarily an integer number of simulation steps, the calculation formula of the t simulation moment at which the cell i just completes emptying is:

[0073]

[0074] Wherein, C(t-Δt) is the emptying road section length of one time step before t moment, l k,p,i is the length of the road section R k,p , C(t) is the emptying road section length at t moment;

[0075] Combined with the calculation formula of the t simulation moment at which the cell i just completes emptying, after switching the variable lane at t moment, the number of lanes of the heavy traffic flow cell changes, the overall density of the cell does not change, but the average single-lane density changes suddenly, and the calculation formula of the traffic density of the heavy traffic flow direction cell is:

[0076]

[0077] Wherein, k k,p,i (t) is the traffic density of the heavy traffic flow direction cell i at t moment, n k,p (t-Δt) is the number of lanes of the heavy traffic flow direction cell i after the variable lane is opened at one time step before t moment, k k,p,i (t-Δt) is the length of the road section R k,p,i , k k,p (t-Δt) is the traffic density of the heavy traffic flow direction cell i at one time step before t moment, l i is the length of the cell i, q i+1 (t-Δt) is the inflow rate of the heavy traffic flow direction cell i+1 at t-Δt moment, q k,p (t-Δt) is the length of the road section R i , q k,p (t-Δt) is the inflow rate of the heavy traffic flow direction cell i at t-Δt moment.

[0078] Based on the VCTM cell transmission model of the road section, the maximum allowable inflow rate of the heavy traffic flow cell is adjusted, and the calculation formula of the maximum allowable inflow rate of the heavy traffic flow cell is:

[0079]

[0080] Wherein, q k,p,max is the maximum allowable inflow rate of the heavy traffic flow cell, N k,p is the length of the road section R k , N k,p is the number of heavy traffic flow direction lanes at the initial moment, n k,p,i(t) represents the number of lanes in the heavy traffic flow direction cell at time t.

[0081] Based on the segment VCTM cell transport model, the congestion density of heavy traffic flow cells is adjusted. The formula for calculating the congestion density of heavy traffic flow cells is as follows:

[0082]

[0083] Where, k k,p,jam For the congestion density of cells in the heavy traffic flow direction, N k For road segment R k,p The number of lanes in the direction of the initial traffic flow, n k,p,i (t) represents the number of lanes in the heavy traffic flow direction cell at time t.

[0084] The transmission capacity of the upstream cell of the recurrent flow direction cell is determined by the following formula:

[0085]

[0086] Among them, S k,p,i-1 (t) represents road segment R k,p The transmission capacity of upstream cell i-1 of cell i in the direction of heavy traffic flow, v free K represents the free-flow velocity in km / h. k,p,i-1 (t) represents road segment R k,p Traffic flow direction cell i-1 at time t has traffic flow density veh / km, Δl is the length of the basic cell, l k,p,i-1 For road segment R k,p The length of cell i-1.

[0087] The receiving capacity of the cell in the direction of repeated traffic flow is determined, and the formula for calculating the receiving capacity of the cell in the direction of repeated traffic flow is as follows:

[0088]

[0089] Among them, R k,p,i (t) represents road segment R k,p The receiving capacity (veh / km) of cell i in the direction of heavy traffic flow, where ω is the queuing wave aggregation velocity (km / h).

[0090] Based on the transmitting capacity of the upstream cell and the receiving capacity of the heavy traffic flow direction cell, the vehicle transfer function of the heavy traffic flow direction cell is determined. The formula for calculating the vehicle transfer function of the heavy traffic flow direction cell is as follows:

[0091] q k,p,i (t)=min{S k,p,i-1 (t),R k,p,i (t)},

[0092] Based on the vehicle transfer function of the heavy traffic flow direction cell, the inflow rate of the heavy traffic flow direction cell is determined. The formula for calculating the inflow rate of the heavy traffic flow direction cell is as follows:

[0093]

[0094] Where, q k,p,i (t) represents road segment R k,p The inflow rate S of cell i in the direction of heavy traffic flow at time t. k,p,i-1 (t) represents road segment R k,p The transmission capacity of upstream cell i-1 of cell i in the direction of heavy traffic flow, R k,p,i (t) represents road segment R k,p The receiving capability of cell i in the direction of heavy traffic flow.

[0095] In some embodiments, for driving safety, it is stipulated that heavy traffic flow vehicles must completely clear a segment of cells before changing lanes to enter the reversible lane. That is, the number of lanes in heavy traffic flow is a sudden change, while light traffic flow vehicles continuously change lanes to leave the reversible lane. Therefore, the concept of dynamic lane count is proposed to describe the gradual change in the number of lanes in light traffic flow, in order to determine the number of lanes in the light traffic flow direction cells. The formula for calculating the number of lanes in the light traffic flow direction cells is:

[0096]

[0097] Where, n′ k,p,i (t) represents the number of lanes in the light traffic flow direction cell at time t, N′ k For road segment R k,p Number of lanes in the light traffic flow direction at initial time, N k,p For the number of lanes to be switched, l k,p,i For road segment R k,p The length of cell i, i k,p For road segment R k,p The last cell number.

[0098] The traffic flow density of the light traffic flow direction cell is determined by the following formula:

[0099]

[0100] Where, k′ k,p,i (t) represents road segment R k,p Traffic flow density in cell i at time t, n′ k,p,i (t-Δt) represents the number of lanes in light traffic flow direction cell i after the variable lanes are opened, at the time step preceding time t, and k′ k,p,i (t-Δt) represents road segment R k,pthe light traffic directional cell i's inflow rate at time t-Δt, q' i L is the length of cell i, q' i (t-Δt) is the length of road segment R k,p the light traffic directional cell i's inflow rate at time t-Δt, q' i-1 (t-Δt) is the length of road segment R k,p the light traffic directional cell i-1's inflow rate at time t-Δt.

[0101] Correspondingly, the calculation formula of the sending capacity of the light traffic directional cell i's upstream cell i+1 is:

[0102]

[0103] wherein, S' k,p,i+1 (t) is the length of road segment R k,p the light traffic directional cell i's upstream cell i+1's sending capacity, v free is the free flow speed (km / h), k' k,p,i+1 (t) is the length of road segment R k,p the light traffic directional cell i's upstream cell i+1's traffic density at time t (veh / km), Δl is the length of the basic cell, l k,p,i+1 is the length of road segment R k,p the length of cell i+1 (m), q' k,p,max is the length of road segment R k,p the maximum allowed inflow rate of the light traffic directional cell.

[0104] The calculation formula of the receiving capacity of the light traffic directional cell i is:

[0105]

[0106] wherein, R' k,p,i (t) is the length of road segment R k,p the light traffic directional cell i's receiving capacity, ω is the queue wave's assembling speed, k' k,p,jam is the jam density of the light traffic directional cell.

[0107] Based on the receiving capacity of the light traffic directional cell i and the sending capacity of the light traffic directional cell i's upstream cell i+1, the vehicle transfer function of the light traffic directional cell i is determined, and the calculation formula of the light traffic directional cell i's vehicle transfer function is:

[0108] q' k,p,i (t) = min{S' k,p,i+1 (t), R' k,p,i (t)},

[0109] Based on the vehicle transfer function of light traffic flow direction cell i, the inflow rate of the light traffic flow direction cell is determined. The formula for calculating the inflow rate of the light traffic flow direction cell is as follows:

[0110]

[0111] Where, q′ k,p,i (t) represents road segment R k,p The inflow rate of light traffic flow direction cell i at time t, S′ k,p,i+1 (t) represents road segment R k,p The transmission capacity of the upstream cell i+1 of cell i in the light traffic flow direction, R′ k,p,i (t) represents road segment R k,p The receiving capability of cell i in the direction of light traffic flow.

[0112] In some embodiments, in step S102, a trunk road lane allocation evaluation mechanism is established to make the lane allocation schemes of the same trunk road on the path more consistent, thereby ensuring the stability of trunk road traffic flow. Based on the trunk road lane allocation evaluation mechanism, by introducing the definition of cellular vehicle travel delay, an objective function is constructed with the goal of minimizing the total path travel delay.

[0113] Intra-cell vehicle travel delay is defined as follows: within a simulation step, a vehicle's confinement within a cell will cause a delay of one time step. The formula for calculating the vehicle delay per unit time in a single cell is as follows:

[0114] D k,p,i (t)=Δt·(k k,p,i (t)·l k,p,i -q k,p,i+1 (t)·Δt),

[0115] Among them, D k,p,i (t) represents the vehicle delay per unit time in a single cell, Δt is the time step, and l k,p,i For road segment R k,p The length of the cell, k k,p,i (t) represents road segment R k,p The traffic flow density q of cell i in the heavy traffic flow direction at time t. k,p,i+1 (t) represents road segment R k,p The inflow rate of cell i+1 in the direction of heavy traffic flow at time t.

[0116] The total travel delay for the p-th segment of trunk road k during the tidal corridor opening period is:

[0117]

[0118] Among them, D k,ptotal travel delay of the pth road section of the arterial road k in the opening period of the tidal corridor, t e is the time step for the variable lane closure.

[0119] The lane allocation scheme of the 2th to nth road section of the arterial road k is evaluated, if the scheme of the next road section of the arterial road k is the same as that of the previous road section, the scheme of the next road section is multiplied by a reward coefficient, otherwise multiplied by a penalty coefficient, combined with the requirement of the minimum total travel delay, an arterial road lane allocation evaluation mechanism is established, and the calculation formula of the arterial road lane allocation evaluation mechanism is:

[0120]

[0121] Wherein, f((k,p-1),(k,p)) is the arterial road lane allocation evaluation mechanism, N k +N k,p is the number of heavy traffic flow direction lane allocation of the road section R k,p , N k +N k,p-1 is the number of heavy traffic flow direction lane allocation of the previous road section R k,p of the road section R k,p-1 , when the ratio of N k +N k,p and N k +N k,p-1 is 1, the lane allocation schemes of the two adjacent road sections are the same.

[0122] The arterial road lane allocation evaluation mechanism is nested into the total travel delay of the pth road section of the arterial road k in the opening period of the tidal corridor, and the minimum path total travel delay is taken as the optimization objective to construct an objective function, and the calculation formula of the objective function is:

[0123]

[0124] Wherein, minD total is the objective function, D k,p,i (t) is the vehicle delay per unit time of a single cell, D k,p is the total travel delay of the pth road section of the arterial road k in the opening period of the tidal corridor, D k,1 is the total travel delay of the 1th road section of the arterial road k in the opening period of the tidal corridor.

[0125] In some embodiments, constraints are set for the objective function. These constraints include at least the saturation degree of heavy traffic flow in the direction of arterial road, the average saturation degree of heavy traffic flow in the direction of arterial road, the saturation degree of light traffic flow in the direction of arterial road, and the average saturation degree of light traffic flow in the direction of arterial road. Saturation degree is an important indicator reflecting road congestion. Since the variable lane setting of road segments is based on arterial roads, the definition of arterial road saturation is introduced here. Arterial road saturation degree can be expressed as the ratio of the sum of traffic volume of each road segment on the arterial road to the total capacity of the arterial road. In the segment cell transmission model, each cell can be regarded as a cross-section for flow detection. The traffic volume of a road segment can be understood as the average value of the transmission flow between all upstream and downstream cells on the road segment. The formula for calculating the constraint condition that the bidirectional saturation degree of the arterial road should satisfy is:

[0126]

[0127]

[0128]

[0129]

[0130] Where, x k (t) represents the saturation degree of the k-fold traffic flow direction on the main road at time t. Let q be the average saturation of traffic flow direction k on the arterial road. k,p,max For road segment R k,p The maximum permissible inflow rate of cells in the direction of heavy traffic flow, x′ k (t) represents the saturation of the light traffic flow direction on the main road at time t. Let k be the average saturation of light traffic flow in the direction of the arterial road.

[0131] In some embodiments, in step S103, after optimizing the cellular transmission model of variable lane segment switching based on the objective function and constraints, a variable lane allocation model for the road segment is established to determine the variable lane allocation scheme for the entire path segment. Considering the spatial distribution characteristics of tidal traffic flow in the road network and the requirements for variable lane setting, the model effectively simulates the continuous change process of traffic flow before and after the opening of the variable lane in the road segment. It can be applied to the calculation of road segment delay under the dynamic switching scenario of variable lanes, ensuring the stability of traffic flow on the main road.

[0132] To better implement the method for constructing the variable lane allocation model for road segments in this invention embodiment, based on the method for constructing the variable lane allocation model for road segments, correspondingly, as follows: Figure 4 As shown, this embodiment of the invention also provides a device for constructing a variable lane allocation model for a road segment. The device 400 for constructing a variable lane allocation model for a road segment includes:

[0133] The cell transmission model construction module 401 is configured to construct a cell transmission model of variable lane section switching to simulate a traffic flow transmission process before and after variable lane switching of a road section.

[0134] The objective function construction module 402 is configured to establish a trunk lane allocation evaluation mechanism, construct an objective function with a minimum path total travel delay as an optimization target based on the trunk lane allocation evaluation mechanism, and set a constraint condition for the objective function.

[0135] The variable lane allocation model construction module 403 is configured to construct a variable lane allocation model of a road section based on the objective function and the constraint condition after optimization of the cell transmission model of variable lane section switching, and determine a variable lane allocation scheme of the road section.

[0136] In summary, the construction method and device of the variable lane allocation model of a road section provided by the present application first construct a cell transmission model of variable lane section switching to simulate a traffic flow transmission process before and after variable lane switching of a road section, then establish a trunk lane allocation evaluation mechanism, construct an objective function with a minimum path total travel delay as an optimization target based on the trunk lane allocation evaluation mechanism, and set a constraint condition for the objective function, and finally construct a variable lane allocation model of a road section based on the objective function and the constraint condition after optimization of the cell transmission model of variable lane section switching, and determine a variable lane allocation scheme of the road section, thereby ensuring the traffic flow stability of a trunk road.

[0137] The above description is only a preferred embodiment of the present application, but the protection scope of the present application is not limited to this. Any change or replacement within the technical range disclosed by the present application can be easily thought by those skilled in the art, and should be covered in the protection scope of the present application.

Claims

1. A method for constructing a variable lane allocation model for a road segment, characterized in that, The application relates to a variable lane allocation model and a variable lane allocation method. The application comprises the following steps: A variable lane segment switching cell transmission model is constructed to simulate the traffic flow transmission process before and after the variable lane switching of a road segment; ， ， ， ， in, Let be the objective function. For vehicle delays per unit time in a single cell, Main road No. Total travel delays on this road segment during the tidal corridor's operating hours. Main road Total travel delays for Route 1 during the tidal corridor's operating hours. For the evaluation mechanism of lane allocation on arterial roads, For road section The number of lanes allocated in the direction of heavy traffic flow. For road section Previous section Lane allocation for heavy traffic flow direction The time step when the reversible lane closes. For road section Heavy traffic flow direction cells upstream cells exist Inflow rate at any given time For road section cell Length, For time step, To determine the simulated step size for activating the tidal lane corridor, For road section Heavy traffic flow direction cells exist Traffic density at any given time For road section The last cell number, For road section Number of lanes in the direction of heavy traffic flow at the initial moment The number of lanes to be switched; An arterial road lane allocation evaluation mechanism is established, a target function with the minimum total travel delay of a path as an optimization objective is constructed based on the arterial road lane allocation evaluation mechanism, and a constraint condition is set for the target function, and the calculation formula of the target function is: ， ， ， ， wherein is the arterial road at time the saturation of the heavy traffic flow direction, is the arterial road the average saturation of the heavy traffic flow direction, is the link the maximum allowed inflow rate of the heavy traffic flow direction cell, is the arterial road at time the saturation of the light traffic flow direction, is the arterial road the average saturation of the light traffic flow direction, is the link the number of lanes of the light traffic flow direction at the initial time is the link the light traffic flow direction cell at the inflow rate at time The constraint condition at least comprises the saturation of a heavy traffic flow direction of an arterial road, the average saturation of the heavy traffic flow direction of the arterial road, the saturation of a light traffic flow direction of the arterial road and the average saturation of the light traffic flow direction of the arterial road, and the calculation formula of the constraint condition is:

2. The method of claim 1, wherein, After the variable lane segment switching cell transmission model is optimized based on the target function and the constraint condition, a variable lane allocation model of a road segment is constructed to determine a variable lane allocation scheme of the road segment. The application comprises the following steps: The uplink direction and the downlink direction of the road segment are determined, wherein the uplink direction is the heavy traffic flow direction and the downlink direction is the light traffic flow direction; The road segment is divided into multiple cells to determine the heavy traffic flow direction cell and the light traffic flow direction cell; 3. The method of claim 2, wherein, The number of lanes of the heavy traffic flow direction cell, the traffic flow density of the heavy traffic flow direction cell, the inflow rate of the heavy traffic flow direction cell, the number of lanes of the light traffic flow direction cell, the traffic flow density of the light traffic flow direction cell and the inflow rate of the light traffic flow direction cell are determined based on the road segment VCTM cell transmission model, and the variable lane segment switching cell transmission model is constructed based on the number of lanes of the heavy traffic flow direction cell, the traffic flow density of the heavy traffic flow direction cell, the inflow rate of the heavy traffic flow direction cell, the number of lanes of the light traffic flow direction cell, the traffic flow density of the light traffic flow direction cell and the inflow rate of the light traffic flow direction cell. ， ， in, for The number of lanes in the cell representing the direction of traffic flow at any given time. For road section Number of lanes in the direction of heavy traffic flow at the initial moment The number of lanes to be switched. for Clear the road segment length at all times. for The length of the cleared segment one time step after the current moment. For road section Cell length, For road section The last cell number, For time step, Number the cells. To determine the simulated step size for activating the tidal lane corridor, At a certain moment, The speed at which light traffic vehicles leave.

4. The method of claim 3, wherein, The calculation formula of the number of lanes of the heavy traffic flow direction cell is: ， ， in, For road section Heavy traffic flow direction cells exist Traffic density at any given time for The length of the cleared segment one time step before the current moment. for The heavy traffic flow direction cell of the previous time step The number of lanes after the reversible lanes are activated. For road section Heavy traffic flow direction cells exist Traffic density at the previous time step For cells Length, For road section Heavy traffic flow direction cells exist Inflow rate at any given time For road section Heavy traffic flow direction cells exist Inflow rate at any given moment.

5. The method of claim 4, wherein, The calculation formula of the traffic flow density of the heavy traffic flow direction cell is: ， wherein, is a road segment heavy traffic flow direction cell at the inflow rate at time instant, is a road segment heavy traffic flow direction cell upstream cell of the sending capacity of, is a road segment heavy traffic flow direction cell the receiving capacity of.

6. The method of claim 5, wherein, The calculation formula of the inflow rate of the heavy traffic flow direction cell is: ， wherein, is the number of lanes of the cell in the light traffic flow direction at the time instant, is the number of lanes of the road segment the number of lanes of the cell in the light traffic flow direction at the initial time instant, is the number of lanes of the pre-switch, is the number of lanes of the road segment the length of the cell is the length of the cell is the number of the last cell of the road segment is the number of the last cell of the road segment 7. The method of claim 6, wherein, The calculation formula of the number of lanes of the light traffic flow direction cell is: ， in, For road section Light traffic flow direction cells exist Traffic density at any given time for Light traffic flow direction cells at the previous time step The number of lanes after the reversible lanes are activated. For road section Light traffic flow direction cells exist Traffic density at the previous time step For cells Length, For road section Light traffic flow direction cells exist Inflow rate at any given time For road section Light traffic flow direction cells upstream cells exist Inflow rate at any given moment.

8. The method of claim 7, wherein, The calculation formula of the traffic flow density of the light traffic flow direction cell is: ， wherein, is a road segment light traffic flow direction cell at the inflow rate at time, is a road segment light traffic flow direction cell upstream cell of the sending capacity of, is a road segment light traffic flow direction cell the receiving capacity of.

9. A device for constructing a variable lane assignment model of a road section, characterized by The calculation formula of the inflow rate of the light traffic flow direction cell is: The application comprises the following steps: The application comprises the following steps: ， ， ， ， in, Let be the objective function. For vehicle delays per unit time in a single cell, Main road No. Total travel delays on this road segment during the tidal corridor's operating hours. Main road Total travel delays for Route 1 during the tidal corridor's operating hours. For the evaluation mechanism of lane allocation on arterial roads, For road section The number of lanes allocated in the direction of heavy traffic flow. For road section Previous section Lane allocation for heavy traffic flow direction The time step when the reversible lane closes. For road section Heavy traffic flow direction cells upstream cells exist Inflow rate at any given time For road section cell Length, For time step, To determine the simulated step size for activating the tidal lane corridor, For road section Heavy traffic flow direction cells exist Traffic density at any given time For road section The last cell number, For road section Number of lanes in the direction of heavy traffic flow at the initial moment The number of lanes to be switched; A variable lane segment switching cell transmission model is constructed to simulate the traffic flow transmission process before and after the variable lane switching of a road segment; ， ， ， ， wherein, is the arterial road at time the saturation of the heavy traffic flow direction, is the arterial road the average saturation of the heavy traffic flow direction, is the link the maximum allowed inflow rate of the heavy traffic flow direction cell, wherein, the arterial road at time the saturation of the light traffic flow direction, is the arterial road the average saturation of the light traffic flow direction, is the link the number of lanes of the light traffic flow direction at the initial time, is the link the light traffic flow direction cell at the initial time, the inflow rate at the initial time; An arterial road lane allocation evaluation mechanism is established, a target function with the minimum total travel delay of a path as an optimization objective is constructed based on the arterial road lane allocation evaluation mechanism, and a constraint condition is set for the target function, and the calculation formula of the target function is: The constraint condition at least comprises the saturation of a heavy traffic flow direction of an arterial road, the average saturation of the heavy traffic flow direction of the arterial road, the saturation of a light traffic flow direction of the arterial road and the average saturation of the light traffic flow direction of the arterial road, and the calculation formula of the constraint condition is: After the variable lane segment switching cell transmission model is optimized based on the target function and the constraint condition, a variable lane allocation model of a road segment is constructed to determine a variable lane allocation scheme of the road segment.

Images