CN103985261B - Based on method for controlling traffic signal lights and the system of vehicle queue length measuring and calculating - Google Patents

Abstract

The traffic signal control method and system based on the measurement and calculation of the vehicle queuing length can accurately simulate the actual traffic flow information by establishing a combined traffic flow model on urban roads and dividing the traffic flow information into a steady flow and a combined flow. By collecting digitized graphics on the road, the pixels in the original map of the digitized graphics can be used as the coordinates of the road, and the sampling time interval can be set. Collect the digitized graphic information of the road at the sampling position again to obtain the starting point where the congestion occurs. According to the distance between the starting point of the congestion and the detection point, the real-time vehicle queue length can be calculated by the vehicle queue length calculation formula. According to the real-time The vehicle queuing length controls the operating status of the signal lights at the upstream intersection, so as to avoid traffic jams at the upstream intersection caused by vehicles entering the congested road at the upstream intersection.

Description

Traffic signal light control method and system based on vehicle queuing length measurement and calculation

technical field

The invention relates to a traffic signal light control technology on roads. In particular, it relates to a traffic signal light control method and system based on vehicle queuing length measurement and calculation.

Background technique

As the number of vehicles continues to rise, urban roads are increasingly congested, resulting in frequent urban road traffic accidents. Once congestion occurs on the road, it will directly reduce the operating efficiency of the road network and easily induce secondary accidents. An effective way to reduce the negative impact of traffic accidents is to calculate the impact of real-time congestion. According to the calculation, the time when the road reaches the maximum queuing length can be obtained, which provides a reliable theoretical basis for taking effective measures to deal with congestion.

Chinese patent document CN102034354A discloses a method for determining the influence range of urban road traffic accidents based on a fixed detector. The method is based on a fixed detector set in the road to detect the departure rate of vehicles, and describes the characteristics of vehicle arrival by using the combined traffic flow of urban roads. According to the arrival rate and departure rate of vehicles, establish a queuing length calculation method based on fixed detectors, and then calculate the maximum queuing length caused by traffic accidents according to the duration of traffic accidents, and determine traffic accidents according to the congestion diffusion process caused by traffic accidents range of influence. The method can calculate the vehicle queuing length caused by traffic accidents occurring in front of the fixed detector along the direction of vehicle travel. And according to the characteristics of urban road traffic lights, the congestion diffusion process caused by traffic accidents is calculated. However, when a traffic accident occurs, the congestion caused by the intersection is cumulative. Once the intersection is locked, it will affect the normal traffic flow at the rear intersection. The methods disclosed in the above-mentioned patent documents cannot calculate the actual positions of all collisions. Poor sex. Simultaneously, the method disclosed in the above-mentioned patent documents also cannot control the running state of the traffic signal lights at the rear crossings of all collision positions in reality, and has poor practicability.

Contents of the invention

For this reason, the technical problem to be solved by the present invention is that in the prior art, it is only possible to calculate the poor versatility and poor practicability caused by the vehicle queuing length caused by the traffic accident ahead of the fixed detector along the direction of travel of the vehicle.

In order to solve the problems of the technologies described above, the technical solution of the present invention is:

The traffic signal control method based on the calculation of vehicle queuing length comprises the following steps:

S1: describe the arrival characteristics of vehicles on the road by establishing a combined traffic flow model on urban roads, calculate the arrival rate of vehicles on the road, and the arrival rate is the number of vehicles entering the road per unit time; further comprising the following steps:

S11: Divide the combined traffic flow into a steady flow and a discrete flow, the steady flow is composed of continuously entering vehicles passing through the through lane at the upstream intersection, and the discrete flow is composed of vehicles entering the left-turn and right-turn lanes at the upstream intersection, The time when the through lane at the upstream intersection starts to release is set as the cycle start time, and the arrival rate of vehicles on the road is:

$\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}$

Among them, λ ₁ is the arrival rate of steady flow, λ ₂ is the arrival rate of discrete flow, g ₁ is the duration of the through lane release at the upstream intersection, c ₁ is the combined traffic flow period, and the combined traffic flow period is equal to the signal period of the upstream intersection ;

S2: Select a certain position in the road as the sampling position, collect the digitized graphics of the road when there is no vehicle driving between the upstream and downstream intersections, and use the acquired digitized graphics as the original map of the road, the starting pixel of the digitized graphics The point corresponds to the starting position downstream of the road, and the pixel point at the end of the digitized graphic corresponds to the ending position upstream of the road;

S3: Select any position on the road as a detection point, and detect the departure rate of vehicles on the road every sampling interval Δt, and the departure rate is the number of vehicles leaving the road per unit time;

S4: When the detection point detects that the vehicle on the road is no longer moving forward within the passing period, collect the digitized graphic information of the road at the sampling position again;

S5: Comparing the obtained digitized graphics with the original map, comparing the difference between the two digitized graphics, obtaining the distance l ₀ from the starting point of the congestion to the detection point, and judging that the location of the congestion is located at the upstream or downstream of the above-mentioned detection point;

S6: According to the distance l ₀ , the position where the congestion occurs, and the time t _s when the detection point detects that the vehicle no longer moves forward within the passing cycle, calculate the real-time vehicle queue length through the vehicle queue length calculation formula;

S7: Set the queuing length of early warning vehicles. When the queuing length of the vehicles reaches the queuing length of the early warning vehicles, it is judged whether the traffic signal lights indicating that the upstream intersection indicates entering the congested road are in a green state; The traffic signal light turns into a red light and remains for a predetermined time, and prolongs the green light time indicating that the vehicle passes to the remaining direction; otherwise, the red light time continues to be extended within the set time; the allowable queue length is set, and when the vehicle queue length reaches When the queue length is allowed to pass, the traffic lights are adjusted to the normal working cycle.

The step of comparing the digitized graphics obtained again with the digitized graphics of the original map in the step S5 is specifically: comparing the different pixels of the two graphics, and identifying the first one from the downstream to the upstream Different pixel points are the locations where congestion occurs.

In the step S6, the following steps are specifically included:

S61: Judging that the location where the congestion occurs is located upstream or downstream of the detection point;

S62: If the location where the congestion occurs is located downstream of the detection point, the distance between the location where the congestion occurs and the detection point is l ₀ , and the detection point detects the time t _s when the vehicle no longer moves forward within the passing cycle, Then, the vehicle queuing length calculation formula is used:

$L\left(t\right)=(N_1+[\frac{t-t_{\mathrm{the\; s}}}{c_1}]\stackrel{\&OverBar;}{\mathrm{\&lambda;}}{c}_1+N_2-\underset{i=1}{\overset{\mathrm{no}}{\mathrm{\&Sigma;}}}{q}_i\mathrm{\&Delta;t})/k_j+l_0,$ Calculate the vehicle queue length;

S63: If the location where the congestion occurs is located upstream of the detection point, the distance between the location where the congestion occurs and the detection point is l ₀ , and the detection point detects the time t _s when the vehicle no longer moves forward within the passing cycle, Then, the vehicle queuing length calculation formula is used:

$L\left(t\right)=(N_1+[\frac{t-t_{\mathrm{the\; s}}}{c_1}]\stackrel{\&OverBar;}{\mathrm{\&lambda;}}{c}_1+N_2-\underset{i=1}{\overset{\mathrm{no}}{\mathrm{\&Sigma;}}}{q}_i\mathrm{\&Delta;t})/k_j+l_0,$ Calculate the vehicle queue length;

Among them, t is any moment when the detection point detects that the vehicle does not move within the road traffic cycle or after the vehicle passes through the detection point, and N ₁ and N ₂ are respectively the location of the combined traffic flow when the vehicle arrives. The number of vehicles arriving within the remaining time of the cycle Δc ₁ and the number of vehicles arriving within the remaining time Δc ₂ of the combined traffic flow at the end of the cycle of congestion diffusion; q _i is the departure rate of vehicles detected in the ith sampling time interval, i is The sequence number of the time interval that the detection point has detected, n is the number of times that the detection point has been detected at any time _t ; kj is the congestion density of the road section, generally taken as 100-150 vehicles/km;

N ₁ : When Δc ₁ >c ₁ -g ₁ , N ₁ =λ ₁ (Δc ₁ -c ₁ +g ₁ )+λ ₂ (c ₁ -g ₁ ), where λ ₁ (Δc ₁ -c ₁ + g ₁ ) is the number of vehicles arriving in the form of steady flow within the remaining time Δc ₁ of the combined traffic flow when the vehicle arrives, and λ ₂ (c ₁ -g ₁ ) is the discrete time within the remaining time Δc ₁ of the combined traffic flow when the vehicle arrives The number of vehicles arriving in the form of flow; when Δc ₁ <c ₁ -g ₁ , N ₁ = λ ₂ c ₁ , at this time, only discrete flow is included in the remaining time Δc ₁ of the cycle of combined traffic flow when the vehicle arrives, and the arriving The number of vehicles is λ ₂ Δc ₁ ; N ₂ : when Δc ₂ <g ₁ , N ₂ = λ ₁ Δc ₂ , at this time, only steady flow is included in the remaining time Δc ₂ of the combined traffic flow at the end of congestion diffusion, and The number of arriving vehicles is λ ₁ Δc ₂ ; when Δc ₂ >g ₁ , N ₂ =λ ₁ g ₁ +λ ₂ (Δc ₂ -g ₁ ), where λ ₁ g ₁ is the combined traffic flow at the end of congestion diffusion The number of vehicles arriving in the form of steady flow within the remaining time Δc ₂ of the cycle, λ ₂ (Δc ₂ -g ₁ ) is the number of vehicles arriving in the form of discrete flow within the remaining time Δc ₂ of the cycle of the combined traffic flow at the end of congestion diffusion.

In the step S4, the detection point no longer moves forward when detecting that the vehicle on the road is passing through the cycle, and this step is specifically:

The detection point detects that the vehicle directly ahead does not move within the road traffic cycle within a predetermined time or when the vehicle does not pass the detection point.

The traffic signal control system based on the calculation of vehicle queuing length includes the following modules:

Traffic flow building module: used to set up urban road combined traffic flow model to describe the arrival characteristics of vehicles on the road, calculate the arrival rate of vehicles on the road, and the arrival rate is the number of vehicles entering the road per unit time; further include:

The arrival rate calculation module is used to divide the combined traffic flow into a stable flow and a discrete flow. The stable flow is composed of continuously entering vehicles released from the through lane at the upstream intersection, and the discrete flow is driven by the left-turn and right-turn lanes at the upstream intersection. The composition of incoming vehicles, the time when the through lane of the upstream intersection starts to release is set as the cycle start time, and the arrival rate of vehicles on the road is:

$\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}$

Among them, λ ₁ is the arrival rate of steady flow, λ ₂ is the arrival rate of discrete flow, g ₁ is the duration of the through lane release at the upstream intersection, c ₁ is the combined traffic flow period, and the combined traffic flow period is equal to the signal period of the upstream intersection ;

Sampling module: select a certain position in the road as the sampling position, collect the digital graphics of the road between the two intersections upstream and downstream when there is no vehicle, and use the obtained digital graphics as the original map of the road. The starting point of the digital graphics is The initial pixel point corresponds to the starting position downstream of the road, and the pixel point at the end of the digitized graphic corresponds to the ending position upstream of the road;

Detection module: select any position on the road as a detection point, and detect the departure rate of vehicles on the road every sampling interval Δt, and the departure rate is the number of vehicles leaving the road per unit time;

Secondary acquisition module: when the detection point detects that the vehicle on the road is no longer moving forward within the passing period, it collects the digitized graphics of the road at the sampling position again;

Comparison module: compare the acquired digital graphics with the original map, compare the difference between the two digital graphics, obtain the distance l ₀ from the starting point of the congestion to the detection point, and judge the location of the congestion located upstream or downstream of said detection point;

Calculation module: according to the distance l ₀ , the position where the congestion occurs, and the time t _s when the detection point detects that the vehicle no longer moves forward in the passing cycle, calculate the real-time vehicle queue length through the vehicle queue length calculation formula;

Traffic signal light control module: set the queuing length of early warning vehicles, and when the queuing length of the vehicles reaches the queuing length of the early warning vehicles, judge whether the traffic signal light indicating that the upstream intersection indicates entering the congested road is in a green light state; The traffic light on the congested road turns red and remains for a predetermined time, and prolongs the green light time indicating that the vehicle passes to the rest of the direction; otherwise, the red light time continues to be extended within the set time; When the queuing length reaches the allowable queuing length, the traffic signal lights are adjusted to a normal working cycle.

The digitized graphics that will be obtained again in the comparison module are compared with the original map, specifically:

Compare the digitized graphics obtained again with the digitized graphics of the original map, mainly compare the different pixels of the two graphics, and identify the first different pixel from the downstream to the upstream, which is the occurrence Congested location.

In the calculation module, the following modules are specifically included:

Position judging module: judging that the position where congestion occurs is located upstream or downstream of the detection point;

The first calculation module: if the location where the congestion occurs is located downstream of the detection point, the distance between the location where the congestion occurs and the detection point is l ₀ , and the moment when the detection point detects that the vehicle no longer moves forward within the passing cycle t _s , then use the vehicle queue length calculation formula:

$L\left(t\right)=(N_1+[\frac{t-t_{\mathrm{the\; s}}}{c_1}]\stackrel{\&OverBar;}{\mathrm{\&lambda;}}{c}_1+N_2-\underset{i=1}{\overset{\mathrm{no}}{\mathrm{\&Sigma;}}}{q}_i\mathrm{\&Delta;t})/k_j+l_0,$ Calculate the vehicle queue length;

The second calculation module: if the location where the congestion occurs is located upstream of the detection point, the distance between the location where the congestion occurs and the detection point is l ₀ , and the moment when the detection point detects that the vehicle no longer moves forward within the passing cycle t _s , then use the vehicle queue length calculation formula:

$L\left(t\right)=(N_1+[\frac{t-t_{\mathrm{the\; s}}}{c_1}]\stackrel{\&OverBar;}{\mathrm{\&lambda;}}{c}_1+N_2-\underset{i=1}{\overset{\mathrm{no}}{\mathrm{\&Sigma;}}}{q}_i\mathrm{\&Delta;t})/k_j+l_0,$ Calculate the vehicle queue length;

Among them, t is any moment when the detection point detects that the vehicle does not move within the road traffic cycle or after the vehicle does not pass the detection point, N ₁ and N ₂ are the remaining time of the cycle of the combined traffic flow when the vehicle arrives. The number of vehicles arriving within time Δc ₁ and the number of vehicles arriving within the remaining time Δc ₂ of the combined traffic flow cycle at the end of congestion diffusion; q _i is the departure rate of vehicles detected in the ith sampling time interval, and i is the The serial number of the time interval that the detection point has been detected, n is the number of times that the detection point has been detected at any time _t ; kj is the congestion density of the road section, generally taken as 100-150 vehicles/km;

N ₁ : When Δc ₁ >c ₁ -g ₁ , N ₁ =λ ₁ (Δc ₁ -c ₁ +g ₁ )+λ ₂ (c ₁ -g ₁ ), where λ ₁ (Δc ₁ -c ₁ + g ₁ ) is the number of vehicles arriving in the form of steady flow within the remaining time Δc ₁ of the combined traffic flow when the vehicle arrives, and λ ₂ (c ₁ -g ₁ ) is the discrete time within the remaining time Δc ₁ of the combined traffic flow when the vehicle arrives The number of vehicles arriving in the form of flow; when Δc ₁ <c ₁ -g ₁ , N ₁ = λ ₂ c ₁ , at this time, only discrete flow is included in the remaining time Δc ₁ of the cycle of combined traffic flow when the vehicle arrives, and the arriving The number of vehicles is λ ₂ Δc ₁ ; N ₂ : when Δc ₂ <g ₁ , N ₂ = λ ₁ Δc ₂ , at this time, only steady flow is included in the remaining time Δc ₂ of the combined traffic flow at the end of congestion diffusion, and The number of arriving vehicles is λ ₁ Δc ₂ ; when Δc ₂ >g ₁ , N ₂ =λ ₁ g ₁ +λ ₂ (Δc ₂ -g ₁ ), where λ ₁ g ₁ is the combined traffic flow at the end of congestion diffusion The number of vehicles arriving in the form of steady flow within the remaining time Δc ₂ of the cycle, λ ₂ (Δc ₂ -g ₁ ) is the number of vehicles arriving in the form of discrete flow within the remaining time Δc ₂ of the cycle of the combined traffic flow at the end of congestion diffusion.

The detection point in the secondary acquisition module will no longer move forward during the passing period when the vehicle on the road is detected, specifically:

The detection point detects that the vehicle directly ahead does not move within the road traffic cycle within a predetermined time or when the vehicle does not pass the detection point.

The above-mentioned technical scheme of the present invention has the following advantages compared with the prior art:

1. The traffic signal light control method and system based on the calculation of vehicle queuing length, through the establishment of a combined traffic flow model on urban roads, the traffic flow information is divided into stable flow and combined flow, which can accurately simulate realistic traffic flow information. By collecting digitized graphics on the road, the pixels in the original map of the digitized graphics can be used as the coordinates of the road, and the sampling time interval can be set to sample and detect the departure rate of vehicles on the road at regular intervals. When the vehicles on the road no longer move forward during the road traffic cycle, collect the digitized graphic information of the road at the sampling position again, and identify the different pixels on the digital graphic information from the original map, Obtain the starting point where the congestion occurs, according to the distance between the starting point of the congestion and the detection point, and the moment when it is detected that the vehicle is no longer moving forward in the passing cycle, the real-time vehicle queue length can be calculated through the vehicle queue length calculation formula, according to the real-time vehicle queue Length, to control the operating status of the signal lights at the upstream intersection, so as to avoid traffic jams at the upstream intersection caused by vehicles entering the congested road at the upstream intersection.

2. The traffic signal light control method and system based on the measurement and calculation of vehicle queuing length compares the digitized graphic information obtained again with the original map, and by comparing the different pixels of the two graphics, it is possible to identify the traffic jam caused by traffic congestion. Digitizes the resulting changes in the map to pinpoint exactly where congestion is occurring.

3. The traffic signal control method and system based on the calculation of vehicle queuing length can calculate the length of vehicle queuing due to congestion after the congestion occurs at any position through the calculation formula of vehicle queuing length according to the position where the congestion occurs.

4. Based on the traffic signal light control method and system based on the calculation of the vehicle queuing length, the detection point can detect that the vehicle does not move within the road cycle, thereby judging that there is congestion on the road.

Description of drawings

In order to make the content of the present invention more easily understood, the present invention will be described in further detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein

Fig. 1 is the flow chart of the traffic signal light control method based on the vehicle queuing length measurement and calculation of an embodiment of the present invention;

Fig. 2 is a schematic diagram of a congestion situation in a traffic signal control method based on vehicle queuing length measurement according to an embodiment of the present invention;

Fig. 3 is a structural block diagram of a traffic signal light control system based on vehicle queuing length measurement and calculation according to an embodiment of the present invention.

The reference signs in the figure are: 1-traffic flow establishment module; 2-sampling module; 3-detection module; 4-secondary collection module; 5-comparison module; 6-calculation module; 7-traffic signal light control module.

detailed description

Example 1

As shown in Figure 1, as an embodiment of the present invention, the traffic signal light control method based on vehicle queuing length measurement, comprises the following steps:

S1: describe the arrival characteristics of vehicles on the road by establishing a combined traffic flow model on urban roads, calculate the arrival rate of vehicles on the road, and the arrival rate is the number of vehicles entering the road per unit time; further comprising the following steps:

S11: Divide the combined traffic flow into a steady flow and a discrete flow, the steady flow is composed of continuously entering vehicles passing through the through lane at the upstream intersection, and the discrete flow is composed of vehicles entering the left-turn and right-turn lanes at the upstream intersection, The time when the through lane at the upstream intersection starts to release is set as the cycle start time, and the arrival rate of vehicles on the road is:

$\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}$

Among them, λ ₁ is the arrival rate of steady flow, λ ₂ is the arrival rate of discrete flow, g ₁ is the duration of the through lane release at the upstream intersection, c ₁ is the combined traffic flow period, and the combined traffic flow period is equal to the signal period of the upstream intersection . As a specific implementation manner, both the steady flow and the discrete flow in this embodiment are measured by a plurality of radar detectors arranged at an upstream crossing.

S2: Select a certain position in the road as the sampling position, collect the digitized graphics of the road when there is no vehicle driving between the upstream and downstream intersections, and use the acquired digitized graphics as the original map of the road, the starting pixel of the digitized graphics The point corresponds to the starting position downstream of the road, and the pixel point at the end of the digitized graphic corresponds to the ending position upstream of the road. As a specific implementation manner, in this embodiment, a camera is used to collect the digitized graphics.

S3: Select any position on the road as a detection point, and detect the departure rate of vehicles on the road every sampling interval Δt, and the departure rate is the number of vehicles leaving the road per unit time. As a specific implementation manner, in this embodiment, the departure rate is collected by a radar data collector.

S4: When the detection point detects that the vehicle on the road does not move forward within the passing period, it collects digitized graphic information of the road at the sampling position again.

S5: Comparing the obtained digitized graphics with the original map, comparing the difference between the two digitized graphics, obtaining the distance l ₀ from the starting point of the congestion to the detection point, and judging that the location of the congestion is located at the upstream or downstream of the above detection point.

S6: Calculate the real-time vehicle queuing length according to the distance l ₀ , the location where the congestion occurs, and the time t _s when the detection point detects that the vehicle no longer moves forward within the passing period, using the vehicle queuing length calculation formula.

S7: Set the queuing length of early warning vehicles. When the queuing length of the vehicles reaches the queuing length of the early warning vehicles (the set early warning queuing length can be: the distance between the starting point of congestion and the upstream intersection minus 5 meters), judge the upstream Whether the traffic signal light at the intersection indicating entering the congested road is in a green state; if yes, turn the traffic signal light indicating entering the congested road into a red light and keep it for a predetermined time, and prolong the green light time for instructing vehicles to pass to other directions; otherwise, in the Continue to extend the red light time within the set time (for example, the green light display time can be extended, and the time can take any value according to needs); set the allowable queue length (the set allowable queue length in the direction can be: the distance between the starting point of congestion and the upstream intersection The distance minus 25 meters), when the vehicle queue length reaches the allowable queue length, adjust the traffic signal lights to the normal working cycle.

The traffic signal control method based on the calculation of vehicle queuing length can accurately simulate the actual traffic flow information by establishing the combined traffic flow model of urban roads and dividing the traffic flow information into stable flow and combined flow. By collecting digitized graphics on the road, the pixels in the original map of the digitized graphics can be used as the coordinates of the road, the sampling time interval is set, and the departure rate of vehicles on the road is detected by sampling at intervals. When the vehicles on the road no longer move forward during the road traffic cycle, collect the digitized graphic information of the road at the sampling position again, and identify the different pixels on the digital graphic information from the original map, Obtain the starting point where the congestion occurs, according to the distance between the starting point of the congestion and the detection point, and the moment when it is detected that the vehicle is no longer moving forward in the passing cycle, the real-time vehicle queue length can be calculated through the calculation formula of the vehicle queue length, according to the real-time vehicle queue Length, to control the operating status of the signal lights at the upstream intersection, so as to avoid traffic jams at the upstream intersection caused by vehicles entering the congested road at the upstream intersection.

Example 2

As an embodiment of the present invention, on the basis of the above-mentioned embodiment 1, the step of comparing the digitized graphics obtained again in the step S5 with the digitized graphics of the original map is specifically: comparing For the different pixels in the two graphics, identify the first different pixel from the downstream to the upstream, which is the location where the congestion occurs.

Based on the traffic signal control method based on the measurement and calculation of the vehicle queuing length, the digitized graphic information obtained again is compared with the original map, and by comparing the different pixels of the two graphics, it is possible to identify the congestion caused by the occurrence of congestion in the digital graphic. , so as to determine the exact location of the congestion.

Example 3

As an embodiment of the present invention, on the basis of the above-mentioned embodiment 1 or 2, the step S6 specifically includes the following steps:

S61: Judging that the location where the congestion occurs is located upstream or downstream of the detection point; as shown in FIG. 2 , the location where the congestion occurs is located downstream of the detection point.

S62: If the location where the congestion occurs is located downstream of the detection point, and the vehicle travels from upstream to downstream; the distance between the location where the congestion occurs and the detection point is l ₀ , and the detection point detects that the vehicle is in the traffic cycle The moment t _s at which no further advance is made, the vehicle queuing length calculation formula is used:

$L\left(t\right)=(N_1+[\frac{t-t_{\mathrm{the\; s}}}{c_1}]\stackrel{\&OverBar;}{\mathrm{\&lambda;}}{c}_1+N_2-\underset{i=1}{\overset{\mathrm{no}}{\mathrm{\&Sigma;}}}{q}_i\mathrm{\&Delta;t})/k_j+l_0,$ Calculate the vehicle queue length.

S63: If the location where the congestion occurs is located upstream of the detection point, the distance between the location where the congestion occurs and the detection point is l ₀ , and the detection point detects the time t _s when the vehicle no longer moves forward within the passing cycle, Then, the vehicle queuing length calculation formula is used:

$L\left(t\right)=(N_1+[\frac{t-t_{\mathrm{the\; s}}}{c_1}]\stackrel{\&OverBar;}{\mathrm{\&lambda;}}{c}_1+N_2-\underset{i=1}{\overset{\mathrm{no}}{\mathrm{\&Sigma;}}}{q}_i\mathrm{\&Delta;t})/k_j+l_0,$ Calculate the vehicle queue length;

Among them, t is any moment when the detection point detects that the vehicle does not move within the road traffic cycle or after the vehicle passes through the detection point, and N ₁ and N ₂ are respectively the location of the combined traffic flow when the vehicle arrives. The number of vehicles arriving within the remaining time of the cycle Δc ₁ and the number of vehicles arriving within the remaining time Δc ₂ of the combined traffic flow at the end of the cycle of congestion diffusion; q _i is the departure rate of vehicles detected in the ith sampling time interval, i is The sequence number of the time interval that the detection point has detected, n is the number of times that the detection point has been detected at any time _t ; kj is the congestion density of the road section, generally taken as 100-150 vehicles/km;

N ₁ : When Δc ₁ >c ₁ -g ₁ , N ₁ =λ ₁ (Δc ₁ -c ₁ +g ₁ )+λ ₂ (c ₁ -g ₁ ), where λ ₁ (Δc ₁ -c ₁ + g ₁ ) is the number of vehicles arriving in the form of steady flow within the remaining time Δc ₁ of the combined traffic flow when the vehicle arrives, and λ ₂ (c ₁ -g ₁ ) is the discrete time within the remaining time Δc ₁ of the combined traffic flow when the vehicle arrives The number of vehicles arriving in the form of flow; when Δc ₁ <c ₁ -g ₁ , N ₁ = λ ₂ c ₁ , at this time, only discrete flow is included in the remaining time Δc ₁ of the cycle of combined traffic flow when the vehicle arrives, and the arriving The number of vehicles is λ ₂ Δc ₁ ; N ₂ : when Δc ₂ <g ₁ , N ₂ = λ ₁ Δc ₂ , at this time, only steady flow is included in the remaining time Δc ₂ of the combined traffic flow at the end of congestion diffusion, and The number of arriving vehicles is λ ₁ Δc ₂ ; when Δc ₂ >g ₁ , N ₂ =λ ₁ g ₁ +λ ₂ (Δc ₂ -g ₁ ), where λ ₁ g ₁ is the combined traffic flow at the end of congestion diffusion The number of vehicles arriving in the form of steady flow within the remaining time Δc ₂ of the cycle, λ ₂ (Δc ₂ -g ₁ ) is the number of vehicles arriving in the form of discrete flow within the remaining time Δc ₂ of the cycle of the combined traffic flow at the end of congestion diffusion.

The traffic signal light control method based on the measurement and calculation of the vehicle queuing length, through the above steps, according to the location where the congestion occurs, and the calculation formula of the vehicle queuing length, can calculate the length of the vehicle queuing due to the congestion after the congestion occurs at any position.

Example 4

As an embodiment of the present invention, on the basis of any one of the above-mentioned embodiments 1-3, the detection point in the step S4 does not move forward during the period when the vehicle on the road is detected. Specifically: when the detection point detects that the vehicle directly in front does not move within the road passage period within the predetermined time (in this embodiment, the first 20 seconds in the passage period is selected as the predetermined time), or the vehicle is not detected to pass the detection point. The time of other numerical values can also be selected as the predetermined time as required, and the object of the present invention can also be achieved.

Based on the traffic signal control method based on the measurement and calculation of the vehicle queue length, the detection point can detect the situation that the vehicle does not move within the road cycle within a predetermined time, so as to judge the occurrence of congestion on the road.

Example 5

As shown in Figure 3, as an embodiment of the present invention, the traffic signal control system based on the vehicle queuing length measurement includes the following modules:

Traffic flow building module 1: used to set up urban road combined traffic flow model to describe the arrival characteristics of vehicles on the road, calculate the arrival rate of vehicles on the road, and the arrival rate is the number of vehicles entering the road per unit time; Further includes:

The arrival rate calculation module is used to divide the combined traffic flow into a stable flow and a discrete flow. The stable flow is composed of continuously entering vehicles released from the through lane at the upstream intersection, and the discrete flow is driven by the left-turn and right-turn lanes at the upstream intersection. The composition of incoming vehicles, the time when the through lane of the upstream intersection starts to release is set as the cycle start time, and the arrival rate of vehicles on the road is:

$\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; g</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}$

Among them, λ ₁ is the arrival rate of steady flow, λ ₂ is the arrival rate of discrete flow, g ₁ is the duration of the through lane release at the upstream intersection, c ₁ is the combined traffic flow period, and the combined traffic flow period is equal to the signal period of the upstream intersection . As a specific implementation manner, both the steady flow and the discrete flow in this embodiment are measured by a plurality of radar detectors arranged at an upstream crossing.

Sampling module 2: select a certain position in the road as the sampling position, collect the digitized graphics of the road when there is no vehicle running between the upstream and downstream intersections, and use the obtained digitized graphics as the original map of the road. The starting pixel point corresponds to the starting position downstream of the road, and the ending pixel point of the digitized graphic corresponds to the ending position upstream of the road. As a specific implementation manner, in this embodiment, a camera is used to collect the digitized graphics.

Detection module 3: select any position on the road as a detection point, detect the departure rate of vehicles on the road every sampling interval Δt, and the departure rate is the number of vehicles leaving the road per unit time. As a specific implementation manner, in this embodiment, the departure rate is collected by a radar detector.

Secondary collection module 4: when the detection point detects that the vehicle on the road does not move forward within the passing period, it collects the digitized pattern of the road again at the sampling position.

Comparison module 5: compare the obtained digitized graphics with the original map, compare the difference between the two digitized graphics, obtain the distance l ₀ from the starting point of the congestion occurrence to the detection point, and judge the congestion occurrence The location is upstream or downstream of said detection point.

Calculation module 6: according to the distance l ₀ , the location where the congestion occurs, and the time t _s when the detection point detects that the vehicle no longer moves forward within the passing cycle, calculate the real-time vehicle queue length through the vehicle queue length calculation formula.

Traffic signal light control module 7: set the queue length of early warning vehicles, and when the vehicle queue length reaches the queue length of early warning vehicles (the set early warning queue length can be: the distance between the starting point of congestion and the upstream intersection minus 5 meters) , judge whether the traffic signal light at the upstream intersection indicating to enter the congested road is in a green state; The green light time in the direction; otherwise, continue to extend the red light time through the intersection signal machine within the set time (for example, the green light display time can be extended, and the time can take any value according to needs); set the allowable queue length (the set allowable direction The queuing length can be: the distance between the starting point of the congestion and the upstream intersection minus 25 meters), when the vehicle queuing length reaches the allowable queuing length, the traffic signal lights are adjusted to the normal working cycle.

The traffic signal light control system based on the calculation of vehicle queuing length is all installed in the controller and implemented by the controller. By establishing a combined traffic flow model on urban roads, the traffic flow information is divided into stable flow and combined flow, which can accurately simulate realistic traffic flow information. By collecting digitized graphics on the road, the pixels in the original map of the digitized graphics can be used as the coordinates of the road, and the sampling time interval can be set to sample and detect the departure rate of vehicles on the road at regular intervals. When the vehicles on the road no longer move forward during the road traffic cycle, collect the digitized graphic information of the road at the sampling position again, and identify the different pixels on the digital graphic information from the original map, Obtain the starting point where the congestion occurs, according to the distance between the starting point of the congestion and the detection point, and the moment when it is detected that the vehicle is no longer moving forward in the passing cycle, the real-time vehicle queue length can be calculated through the vehicle queue length calculation formula, according to the real-time vehicle queue Length, to control the operating status of the signal lights at the upstream intersection, so as to avoid traffic jams at the upstream intersection caused by vehicles entering the congested road at the upstream intersection.

Example 6

As an embodiment of the present invention, on the basis of the above-mentioned embodiment 5, the digitized graphics obtained again in the comparison module 5 are compared with the original map, specifically:

When a collision occurs, obtain a digitized graph of the road again at the same location (the digitized graph is in pixels, and the pixels can be used as coordinates), and compare it with the digitized graph of the original map. The different pixels of the graph are identified, and the first different pixel from the downstream to the upstream is identified, which is the location where the congestion occurs.

The traffic signal control system based on the measurement and calculation of the vehicle queue length compares the digital graphic information obtained again with the original map, and by comparing the different pixels of the two graphics, it can identify the congestion caused by the occurrence of congestion in the digital graphic. , so as to determine the exact location of the congestion.

Example 7

As an embodiment of the present invention, on the basis of the above-mentioned embodiment 5 or 6, the calculation module 6 specifically includes the following modules:

Position judging module: judging that the position where congestion occurs is located upstream or downstream of the detection point;

The first calculation module: if the location where the congestion occurs is located downstream of the detection point, and the vehicle travel direction is from upstream to downstream; the distance between the location where the congestion occurs and the detection point is l ₀ , and the detection point detects a vehicle At the moment t _s when no longer moving forward in the passing cycle, the vehicle queuing length calculation formula is used:

$L\left(t\right)=(N_1+[\frac{t-t_{\mathrm{the\; s}}}{c_1}]\stackrel{\&OverBar;}{\mathrm{\&lambda;}}{c}_1+N_2-\underset{i=1}{\overset{\mathrm{no}}{\mathrm{\&Sigma;}}}{q}_i\mathrm{\&Delta;t})/k_j+l_0,$ Calculate the vehicle queue length;

The second calculation module: if the location where the congestion occurs is located upstream of the detection point, and the vehicle travels from upstream to downstream; the distance between the location where the congestion occurs and the detection point is l ₀ , and the detection point detects a vehicle At the moment t _s when no longer moving forward in the passing cycle, the vehicle queuing length calculation formula is used:

$L\left(t\right)=(N_1+[\frac{t-t_{\mathrm{the\; s}}}{c_1}]\stackrel{\&OverBar;}{\mathrm{\&lambda;}}{c}_1+N_2-\underset{i=1}{\overset{\mathrm{no}}{\mathrm{\&Sigma;}}}{q}_i\mathrm{\&Delta;t})/k_j+l_0,$ Calculate the vehicle queue length;

Among them, t is any moment when the detection point detects that the vehicle does not move within the road traffic cycle or after the vehicle does not pass the detection point, N ₁ and N ₂ are the remaining time of the cycle of the combined traffic flow when the vehicle arrives. The number of vehicles arriving within time Δc ₁ and the number of vehicles arriving within the remaining time Δc ₂ of the combined traffic flow cycle at the end of congestion diffusion; q _i is the departure rate of vehicles detected in the ith sampling time interval, and i is the The serial number of the time interval that the detection point has been detected, n is the number of times that the detection point has been detected at any time _t ; kj is the congestion density of the road section, generally taken as 100-150 vehicles/km;

N ₁ : When Δc ₁ >c ₁ -g ₁ , N ₁ =λ ₁ (Δc ₁ -c ₁ +g ₁ )+λ ₂ (c ₁ -g ₁ ), where λ ₁ (Δc ₁ -c ₁ + g ₁ ) is the number of vehicles arriving in the form of steady flow within the remaining time Δc1 of the combined traffic flow when the vehicle arrives, and λ ₂ (c ₁ -g ₁ ) is the discrete flow within the remaining time Δc ₁ of the combined traffic flow when the vehicle arrives The number of vehicles arriving in the form; when Δc ₁ <c ₁ -g ₁ , N ₁ = λ ₂ c ₁ , at this time, only discrete flows are included in the remaining time Δc ₁ of the combined traffic flow period when the vehicle arrives, and the arriving vehicles The number is λ ₂ Δc ₁ ; N ₂ : when Δc ₂ <g ₁ , N ₂ = λ ₁ Δc ₂ , at this time, only steady flow is included in the remaining time Δc ₂ of the combined traffic flow at the end of the congestion diffusion period, and the arrival The number of vehicles is λ ₁ Δc ₂ ; when Δc ₂ >g ₁ , N ₂ = λ ₁ g ₁ +λ ₂ (Δc ₂ -g ₁ ), where λ ₁ g ₁ is the combined traffic flow at the end of congestion diffusion The number of vehicles arriving in the form of steady flow in the remaining time of the cycle Δc ₂ , λ ₂ (Δc ₂ -g ₁ ) is the number of vehicles arriving in the form of discrete flow in the remaining time Δc ₂ of the cycle where the combined traffic flow is at the end of the congestion diffusion period.

The traffic signal light control system based on the calculation of vehicle queuing length can calculate the length of vehicle queuing due to congestion after the congestion occurs at any position through the above module, according to the position of the judgment of the congestion, and through the calculation formula of the vehicle queuing length.

Example 8

As an embodiment of the present invention, on the basis of any of the above-mentioned 5-7 embodiments, the detection point does not move forward after detecting that the vehicle on the road is in the passing period, specifically:

The detection point detects that the vehicle directly ahead does not move within the road passage period or that the vehicle does not pass the detection point within the predetermined time (in this embodiment, the first 20 seconds in the passage period is selected as the predetermined time). The time of other numerical values can also be selected as the predetermined time as required, and the object of the present invention can also be achieved.

Based on the traffic signal control system based on the calculation of vehicle queuing length, the detection point can detect the situation that the vehicle does not move within the road cycle within a predetermined time, so as to judge the occurrence of congestion on the road. .

Apparently, the above-mentioned embodiments are only examples for clear description, rather than limiting the implementation. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. It is not necessary and impossible to exhaustively list all the implementation manners here. And the obvious changes or changes derived therefrom are still within the scope of protection of the present invention.

Claims (8)

1., based on the method for controlling traffic signal lights of vehicle queue length measuring and calculating, it is characterized in that, comprise the following steps:

S1: describe by setting up urban road combination traffic flow model the arrival feature that road gets on the bus, calculate the arrival rate of vehicle on described road, described arrival rate is the vehicle number entering described road in the unit time; Further comprising the steps:

S11: described combination traffic flow is divided into steady flow and discrete flow, the vehicle that sails into continuously that described steady flow is let pass by crossing, upstream Through Lane is formed, discrete flow is made up of the vehicle that turn left in crossing, upstream and right-turn lane sails into, the time being started by crossing, upstream Through Lane to let pass is set to Period Start Time, and on described road, the arrival rate of vehicle is:

$\stackrel{\&OverBar;}{\mathrm{\&lambda;}}=\frac{g_1}{c_1}({\mathrm{\&lambda;}}_1-{\mathrm{\&lambda;}}_2)+{\mathrm{\&lambda;}}_2$

Wherein, λ ₁for the arrival rate of steady flow, λ ₂for the arrival rate of discrete flow, g ₁for the duration that crossing, upstream Through Lane is let pass, c ₁for combination the traffic flow cycle, and combination the traffic flow cycle equal the upstream crossing signals cycle;

S2: to choose in road a certain position as sampling location, gather the digitizing figure of road when travelling without vehicle between upstream and downstream two crossings, using the digitizing figure that the gets original map as described road, the reference position in the corresponding road downstream of starting pixels point of described digitizing figure, the end position of the corresponding road upstream of the pixel that described digitizing figure terminates;

S3: select optional position as check point on described road, detects the rate of leaving away of vehicle on described road every sampling interval Δ t, described in the rate of leaving away be in the unit time, leave the vehicle number of described road;

S4: described check point, when detecting that the vehicle on described road does not readvance within the current cycle, gathers the digitizing graphical information of described road again in described sampling location;

S5: by the digitizing figure again got, compare with described original map, the difference of comparison two width digitizing figure, the start point distance that obtaining blocks up occurs is from the distance l of check point ₀, and the position occurred that judges to block up is positioned at upstream or the downstream of described check point;

S6: according to described distance l ₀, and the position got congestion, and described check point detects the moment t that vehicle does not readvance within the current cycle _s, calculate real-time vehicle queue length by vehicle queue length measure formula;

S7: setting early warning vehicle queue length, when described vehicle queue length reaches described early warning vehicle queue length, judges that crossing, upstream indicates the traffic lights entering the road that gets congestion whether to be in green light phase; Be that the traffic lights then instruction being entered the road that gets congestion become red light and keep the schedule time, and extend the green time of instruction vehicle pass-through to all the other directions; Otherwise, continue to extend red time in setting-up time; Setting allows clearance queue length, when described vehicle queue length reaches described permission clearance queue length, traffic lights is adjusted to the normal workweek phase.

2. the method for controlling traffic signal lights based on vehicle queue length measuring and calculating according to claim 1, it is characterized in that, the digitizing figure will again got in described step S5, be specially from the digitizing figure of described original map this step of comparing: the pixel that comparison two width figure is different, to identify from downstream to upstream first different pixel, be the position got congestion.

3. the method for controlling traffic signal lights based on vehicle queue length measuring and calculating according to claim 1 and 2, is characterized in that, in described step S6, specifically comprise the following steps:

S61: judge that the position got congestion is positioned at upstream or the downstream of described check point;

S62: if the position got congestion is positioned at the downstream of described check point, the distance of the position got congestion and described check point is l ₀, and described check point detects the moment t that vehicle does not readvance within the current cycle _s, then by vehicle queue length measure formula:

$L\left(t\right)=(N_1+\&lsqb;\frac{t-t_s}{c_1}\&rsqb;\stackrel{\&OverBar;}{\mathrm{\&lambda;}}{c}_1+N_2-\underset{i=1}{\overset{n}{\&Sigma;}}{q}_i\mathrm{\&Delta;}t)/k_j+l_0,$ Calculate vehicle queue length;

S63: if the position got congestion is positioned at the upstream of described check point, the distance of the position got congestion and described check point is l ₀, and described check point detects the moment t that vehicle does not readvance within the current cycle _s, then by vehicle queue length measure formula:

$L\left(t\right)=(N_1+\&lsqb;\frac{t-t_s}{c_1}\&rsqb;\stackrel{\&OverBar;}{\mathrm{\&lambda;}}{c}_1+N_2-\underset{i=1}{\overset{n}{\&Sigma;}}{q}_i\mathrm{\&Delta;}t)/k_j-l_0,$ Calculate vehicle queue length;

Wherein, t is that described check point detects that vehicle when not being moved or do not detect that vehicle is by any time after described check point, N within the road cycle ₁and N ₂be respectively combination traffic flow place Δ c excess time in cycle when vehicle arrives ₁traffic flow place Δ c excess time in cycle is combined at the end of the vehicle number of interior arrival and diffusion of blocking up ₂the vehicle number of interior arrival; q _ibe the vehicle departing rate detected in i-th sampling time interval, i is the sequence number in the time interval that described check point is detected, and n is the number of times be detected to described check point during any time t; k _jfor section jam density, be taken as 100-150 car/kilometer;

N ₁: as Δ c ₁> c ₁-g ₁time, N ₁=λ ₁(Δ c ₁-c ₁+ g ₁)+λ ₂(c ₁-g ₁), wherein λ ₁(Δ c ₁-c ₁+ g ₁) for combining traffic flow place Δ c excess time in cycle when vehicle arrives ₁the interior vehicle number arrived with steady flow form, λ ₂(c ₁-g ₁) for combining traffic flow place Δ c excess time in cycle when vehicle arrives ₁within discrete flow form arrive vehicle number; As Δ c ₁< c ₁-g ₁time, N ₁=λ ₂c ₁, now, combination traffic flow place Δ c excess time in cycle when vehicle arrives ₁inside only comprise discrete flow, and the vehicle number arrived is λ ₂Δ c ₁; N ₂: as Δ c ₂< g ₁time, N ₂=λ ₁Δ c ₂, now, at the end of diffusion of blocking up, combine traffic flow place Δ c excess time in cycle ₂inside only comprise steady flow, and the vehicle number arrived is λ ₁Δ c ₂; As Δ c ₂> g ₁time, N ₂=λ ₁g ₁+ λ ₂(Δ c ₂-g ₁), wherein, λ ₁g ₁for combining traffic flow place Δ c excess time in cycle at the end of diffusion of blocking up ₂the interior vehicle number arrived with steady flow form, λ ₂(Δ c ₂-g ₁) for combining traffic flow place Δ c excess time in cycle at the end of diffusion of blocking up ₂the interior vehicle number arrived with discrete flow form.

4. the method for controlling traffic signal lights based on vehicle queue length measuring and calculating according to claim 1 and 2, it is characterized in that, check point described in described step S4 is detecting that the vehicle on described road does not readvance within the current cycle, and this step is specially:

When described check point detects that the vehicle in dead ahead is not moved within the road cycle in the given time or vehicle passing detection point do not detected.

5., based on the traffic light control system of vehicle queue length measuring and calculating, it is characterized in that, comprise with lower module:

Module is set up in traffic flow: for setting up the arrival feature that urban road combination traffic flow model to be got on the bus to describe road, calculate the arrival rate of vehicle on described road, described arrival rate is the vehicle number entering described road in the unit time; Comprise further:

Arrival rate computing module, for described combination traffic flow is divided into steady flow and discrete flow, the vehicle that sails into continuously that described steady flow is let pass by crossing, upstream Through Lane is formed, discrete flow is made up of the vehicle that turn left in crossing, upstream and right-turn lane sails into, the time being started by crossing, upstream Through Lane to let pass is set to Period Start Time, and on described road, the arrival rate of vehicle is:

$\stackrel{\&OverBar;}{\mathrm{\&lambda;}}=\frac{g_1}{c_1}({\mathrm{\&lambda;}}_1-{\mathrm{\&lambda;}}_2)+{\mathrm{\&lambda;}}_2$

Wherein, λ ₁for the arrival rate of steady flow, λ ₂for the arrival rate of discrete flow, g ₁for the duration that crossing, upstream Through Lane is let pass, c ₁for combination the traffic flow cycle, and combination the traffic flow cycle equal the upstream crossing signals cycle;

Sampling module: to choose in road a certain position as sampling location, gather the digitizing figure of road during travelling without vehicle between upstream and downstream two crossings, using the digitizing figure that the gets original map as described road, the reference position in the corresponding road downstream of starting pixels point of described digitizing figure, the end position of the corresponding road upstream of the pixel that described digitizing figure terminates;

Detection module: select optional position as check point on described road, detects the rate of leaving away of vehicle on described road every sampling interval Δ t, described in the rate of leaving away be in the unit time, leave the vehicle number of described road;

Secondary acquisition module: described check point, when detecting that the vehicle on described road does not readvance within the current cycle, gathers the digitizing figure of described road again in described sampling location;

Comparing module: by the digitizing figure again got, compare with described original map, the difference of comparison two width digitizing figure, the start point distance that obtaining blocks up occurs is from the distance l of check point ₀, and the position occurred that judges to block up is positioned at upstream or the downstream of described check point;

Computing module: according to described distance l ₀, and the position got congestion, and described check point detects the moment t that vehicle does not readvance within the current cycle _s, calculate real-time vehicle queue length by vehicle queue length measure formula;

Traffic signal control module: setting early warning vehicle queue length, when described vehicle queue length reaches described early warning vehicle queue length, judges that crossing, upstream indicates the traffic lights entering the road that gets congestion whether to be in green light phase; Be that the traffic lights then instruction being entered the road that gets congestion become red light and keep the schedule time, and extend the green time of instruction vehicle pass-through to all the other directions; Otherwise, continue to extend red time in setting-up time; Setting allows clearance queue length, when described vehicle queue length reaches described permission clearance queue length, traffic lights is adjusted to the normal workweek phase.

6. the traffic light control system based on vehicle queue length measuring and calculating according to claim 5, is characterized in that the digitizing figure will again got in described comparing module is compared with described original map, is specially:

By the digitizing figure again got, compare with the digitizing figure of described original map, the pixel that comparison two width figure is different, identifies from downstream to first of upstream different pixel, is the position got congestion.

7. the traffic light control system based on vehicle queue length measuring and calculating according to claim 5 or 6, is characterized in that, in described computing module, specifically comprise with lower module:

Position judging module: judge that the position got congestion is positioned at upstream or the downstream of described check point;

First computing module: if the position got congestion is positioned at the downstream of described check point, the distance of the position got congestion and described check point is l ₀, and described check point detects the moment t that vehicle does not readvance within the current cycle _s, then by vehicle queue length measure formula:

$L\left(t\right)=(N_1+\&lsqb;\frac{t-t_s}{c_1}\&rsqb;\stackrel{\&OverBar;}{\mathrm{\&lambda;}}{c}_1+N_2-\underset{i=1}{\overset{n}{\&Sigma;}}{q}_i\mathrm{\&Delta;}t)/k_j+l_0,$ Calculate vehicle queue length;

Second computing module: if the position got congestion is positioned at the upstream of described check point, the distance of the position got congestion and described check point is l ₀, and described check point detects the moment t that vehicle does not readvance within the current cycle _s, then by vehicle queue length measure formula:

$L\left(t\right)=(N_1+\&lsqb;\frac{t-t_s}{c_1}\&rsqb;\stackrel{\&OverBar;}{\mathrm{\&lambda;}}{c}_1+N_2-\underset{i=1}{\overset{n}{\&Sigma;}}{q}_i\mathrm{\&Delta;}t)/k_j-l_0,$ Calculate vehicle queue length;

Wherein, t is that described check point detects that vehicle when not being moved or any time after vehicle passing detection point do not detected, N within the road cycle ₁and N ₂be respectively combination traffic flow place Δ c excess time in cycle when vehicle arrives ₁traffic flow place Δ c excess time in cycle is combined at the end of the vehicle number of interior arrival and diffusion of blocking up ₂the vehicle number of interior arrival; q _ibe the vehicle departing rate detected in i-th sampling time interval, i is the sequence number in the time interval that described check point is detected, and n is the number of times be detected to described check point during any time t; k _jfor section jam density, be taken as 100-150 car/kilometer;

N ₁: as Δ c ₁> c ₁-g ₁time, N ₁=λ ₁(Δ c ₁-c ₁+ g ₁)+λ ₂(c ₁-g ₁), wherein λ ₁(Δ c ₁-c ₁+ g ₁) for combining traffic flow place Δ c excess time in cycle when vehicle arrives ₁the interior vehicle number arrived with steady flow form, λ ₂(c ₁-g ₁) for combining traffic flow place Δ c excess time in cycle when vehicle arrives ₁within discrete flow form arrive vehicle number; As Δ c ₁< c ₁-g ₁time, N ₁=λ ₂c ₁, now, combination traffic flow place Δ c excess time in cycle when vehicle arrives ₁inside only comprise discrete flow, and the vehicle number arrived is λ ₂Δ c ₁; N ₂: as Δ c ₂< g ₁time, N ₂=λ ₁Δ c ₂, now, at the end of diffusion of blocking up, combine traffic flow place Δ c excess time in cycle ₂inside only comprise steady flow, and the vehicle number arrived is λ ₁Δ c ₂; As Δ c ₂> g ₁time, N ₂=λ ₁g ₁+ λ ₂(Δ c ₂-g ₁), wherein, λ ₁g ₁for combining traffic flow place Δ c excess time in cycle at the end of diffusion of blocking up ₂the interior vehicle number arrived with steady flow form, λ ₂(Δ c ₂-g ₁) for combining traffic flow place Δ c excess time in cycle at the end of diffusion of blocking up ₂the interior vehicle number arrived with discrete flow form.

8. the traffic light control system based on vehicle queue length measuring and calculating according to any one of claim 5 or 6, it is characterized in that, described check point in described secondary acquisition module is detecting that the vehicle on described road does not readvance within the current cycle, is specially:

When described check point detects that the vehicle in dead ahead is not moved within the road cycle in the given time or vehicle passing detection point do not detected.