Variable lane switching and signal timing method based on signal intersection operation conditionTechnical Field
The invention relates to the technical field of traffic signal control, in particular to a variable lane switching and signal timing method based on the running condition of a signalized intersection.
Background
With the development of cities, the quantity of motor vehicles kept is continuously increased, and the urban congestion phenomenon is gradually aggravated. However, compared with the increasing rate of motor vehicles in cities, the building rate of urban roads is much lower, meanwhile, the cost of newly-built and newly-built roads is higher, the building period of road facilities is long, the requirements are difficult to meet in a short time, and the expected implementation effect cannot be achieved. Therefore, under the existing road resource condition, the utilization efficiency of the road is improved to the maximum extent, and a scientific traffic control scheme is formulated, so that the method becomes a main way for relieving traffic jam and a key problem to be solved by traffic researchers.
The variable lanes at the entrance of the signalized intersection are used as one of tidal traffic, and traffic at the intersection is effectively organized by changing the driving directions or driving types on certain lanes at different time intervals, so that the space-time resources of the existing roads are fully utilized, and the problem of traffic jam at the intersection due to unbalanced steering is solved as effectively as possible. Currently, variable lanes have been implemented in multiple cities.
The existing variable lane switching control method has the following disadvantages: (1) the variable lane is switched regularly, so that the variable lane can not adapt to the daily flow change condition; (2) the variable lanes are unassigned with the signals; (3) the variable lane switch after congestion occurs can cause the vehicles originally accumulated on the variable lane to be unable to pass.
Disclosure of Invention
In order to overcome the defects, the invention aims to provide a variable lane switching and signal timing method based on the running condition of the signalized intersection, which can enable the lane allocation and signal timing of the intersection to be more fit with the actual traffic running rule, effectively improve the road traffic efficiency and reduce the traffic delay.
In order to achieve the above purpose, the invention adopts the following technical scheme: a variable lane switching and signal timing method based on the running condition of a signalized intersection comprises the following steps: s1, collecting data, arranging traffic flow detection equipment at an intersection, and collecting basic data of a signalized intersection; s2, setting a threshold value, and setting a variable lane switching threshold value according to basic data of the signalized intersection; s3, adjusting timing, namely adjusting signal timing of a signalized intersection according to traffic running conditions after the lane change; s4, scheme simulation optimization, namely simulating the scheme, carrying out tracking evaluation on the implementation effect, and optimizing the scheme according to the evaluation result.
Preferably, the signal intersection basic data in the step S1 includes static signal intersection basic information and dynamic signal intersection basic information, where the static signal intersection basic information includes the number of lanes of the direction of the entrance lane, canalization setting data, and detector arrangement data, and the dynamic signal intersection basic information includes current signal phase sequence design and timing setting data of the signal intersection, and traffic operation flow data of the signal intersection.
Preferably, the step S1 of arranging the traffic flow detection device at the intersection includes arranging a coil device at the stop line or arranging a microwave detector and a video detector in opposite directions.
Preferably, the variable lane switching threshold is set in step S2 on the condition that the number of lanes in the direction of the entrance lane is smaller than 4, and no variable lane is set when the number of lanes in the direction of the entrance lane is smaller than 4.
Preferably, the step S2 sets a variable lane switching threshold on the condition of the traffic and the actual traffic capacity of the intersection, and switches the variable lane when changing the variable lane attribute will increase the traffic and the actual traffic capacity of the intersection; the variable lane remains unchanged when changing the variable lane properties will leave the actual traffic capacity of the traffic and intersection unchanged or even decline.
Further, 5 calculation formulas are established according to the flow and the actual traffic capacity of the intersection:
(1) the initial traffic capacity of the left turn phase of the signalized intersection is as follows:
wherein: s is SL -saturated flow of left turn phase before variable lane properties become straight going;
gL -signal intersection left turn phase green light duration;
c, signal timing period;
(2) the initial traffic capacity of the signal intersection straight phase is as follows:
wherein:
SS -saturated flow of straight-going phase before variable lane properties become straight-going;
gs -signal intersection straight-going phase green light duration;
(2) the traffic capacity of the left turn phase of the intersection after the attribute of the lane at the signal intersection is changed from left to straight is as follows:
wherein:
b-the number of initial left-turning lanes at the intersection;
m-variable number of lanes;
S′L -a left turn steering saturation flow rate after a variable lane change;
(4) the traffic capacity of the straight-going phase after the property of the lane at the signal intersection is changed from left to straight-going is as follows:
wherein:
a, the number of initial left-turning lanes at the intersection;
S′s -is the straight steering saturation flow rate after a variable lane change;
(5) the traffic capacity change value of the whole signalized intersection before and after the change of the variable lane attribute is as follows:
wherein:
qS -the arrival rate of the straight vehicles at the intersection at the entrance of the lane which is variable, in veh/s;
qL -the arrival rate of the left-turn vehicles at the intersection at the entrance lane of the variable lane in veh/s;
y—total flow ratio of initial protocol;
the total loss time of the signal phase of the L-signal intersection is s;
when the variable lane switching threshold isWhen the flow and the actual traffic capacity of the intersections are increased,the changeable lane is switched at this time; when the variable lane switching threshold is +.>The actual traffic capacity of the flow and the intersection is unchanged or even reduced, and when the variable lane keeps unchanged, the actual traffic capacity of the flow and the intersection is unchanged or even reduced, and when the variable lane keeps unchanged.
Further, step S2.5 is added between step S2 and step S3: the traffic flow detection equipment and the variable lane indicator are connected into a annunciator, the values of a, b and m in a threshold model are input, and a trigger statement is set in the annunciator to realize automatic switching of the variable lane.
Preferably, the traffic operation condition in the step S3 includes intersection canalization data, traffic supply data, intersection flow ratio, traffic capacity and traffic flow variation data between different directions of the intersection.
Further, according to the signal timing and the traffic running condition in the step S3, 5 calculation formulas are established:
(1) the intersection flow ratio after the lane change is:
wherein:
the total flow ratio after the attribute of the variable lane at the entrance of the Y' -signalized intersection is changed;
k-total flow ratio before changing the attribute of the variable lane at the intersection entrance;
yS -a flow ratio of the straight-going phase before the variable lane property becomes straight-going;
yL -flow ratio of left turn phase before variable lane properties become straight;
(2) according to the Webster model, the signal timing period is:
(3) inlet channel of signal intersectionThe effective green time of the left-turning phase of the entrance road after the attribute of the variable lane is changed is as follows:
(4) the effective green time of the straight phase of the entrance road after the attribute of the variable lane of the entrance road of the signalized intersection is changed is as follows:
(5) the effective green time of other phases after the attribute of the variable lane of the entrance lane of the signalized intersection is changed is as follows:wherein:
yi -the other phase, the original flow ratio, when the properties of the variable lanes of the signalized intersection entrance are changed.
Preferably, the implementation effect in the step S4 includes data comparison analysis.
The variable lane switching and signal timing method based on the running condition of the signalized intersection has the beneficial effects that:
(1) and setting a threshold according to the actual traffic running condition, and automatically switching the variable lanes when the condition meets the threshold to adapt to the daily flow change condition.
(2) And the variable lane change condition is linked with signal timing, and intersection phase timing is synchronously adjusted after the variable lane is switched.
(3) And setting a variable lane switching threshold value from the angle of intersection traffic capacity change, and controlling road congestion in advance.
Drawings
Fig. 1 is a schematic diagram of lane layout and traffic flow detection apparatus layout.
Detailed Description
The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making clear and defining the scope of the present invention.
Referring to fig. 1, a method for switching variable lanes and timing signals based on the operation condition of a signalized intersection comprises the following steps:
s1, arranging traffic flow detection equipment at an intersection to acquire basic data of a signalized intersection; in order to acquire more accurate traffic flow data, coil equipment is required to be arranged at an intersection stop line, or equipment such as a microwave detector, a video detector and the like are oppositely arranged and traffic operation basic parameters at an entrance stop line are detected, the acquired signal intersection basic data comprise signal intersection static basic information and signal intersection dynamic basic information, the signal intersection dynamic basic information comprises signal intersection current signal phase sequence design and timing setting data and signal intersection traffic operation flow data, and the signal intersection static basic information comprises entrance lane direction lane number, canalization setting data and detector arrangement data;
s2, setting a variable lane switching threshold according to basic data of the signalized intersection; in order to ensure that the effect of the variable lanes is effectively exerted, when the variable lane switching threshold is set, the number of lanes in the direction of an entrance lane of the variable lanes is more than or equal to 4 so as to ensure that special straight, left-turn, right-turn and variable lanes are arranged at the entrance lane of an intersection, and if the variable lanes are arranged at the intersection with fewer lanes in the entrance lane and larger traffic volume, the delay increase of other phase vehicles is possibly caused, and negative influence is caused; the variable lane switching threshold is conditioned on the actual traffic capacity of the traffic and the intersection, and switches the variable lanes when changing the variable lane attributes would increase the actual traffic capacity of the traffic and the intersection, and keeps the variable lanes unchanged when changing the variable lane attributes would keep the actual traffic capacity of the traffic and the intersection unchanged or even decrease;
the initial throughput for the left turn phase of the signalized intersection is:
wherein: s is SL -saturated flow of left turn phase before variable lane properties become straight going;
gL -signal intersection left turn phase green light duration;
c, signal timing period;
the initial throughput for the signalized intersection straight phase is:
wherein:
SS -saturated flow of straight-going phase before variable lane properties become straight-going;
gS -signal intersection straight-going phase green light duration;
when the attribute of the lane at the intersection is changed from left to straight, the traffic capacity of the left turn phase of the intersection is as follows:
wherein:
b-the number of initial left-turning lanes at the intersection;
m-variable number of lanes;
S′L -a left turn steering saturation flow rate after a variable lane change;
when the attribute of the lane at the intersection is changed from left to straight, the traffic capacity of the straight-going phase is as follows:
wherein:
a, the number of initial left-turning lanes at the intersection;
S′S -is the straight steering saturation flow rate after a variable lane change;
the traffic capacity change value of the whole signalized intersection before and after the change of the variable lane attribute is as follows:
wherein:
qS -the arrival rate of the straight vehicles at the intersection at the entrance of the lane which is variable, in veh/s;
qL -the arrival rate of the left-turn vehicles at the intersection at the entrance lane of the variable lane in veh/s;
y—total flow ratio of initial protocol;
the total loss time of the signal phase of the L-signal intersection is s;
therefore, when the variable lane switching threshold isWhen the traffic and the actual traffic capacity of the intersection are increased, the changeable lane can be switched at the moment; when the variable lane switching threshold is +.>The actual traffic capacity of the flow and the intersection is unchanged or even reduced, when the variable lane keeps unchanged, the actual traffic capacity of the flow and the intersection is unchanged or even reduced, and when the variable lane keeps unchanged;
in order to realize automatic switching of the variable lanes under the condition that the threshold value is met, the built traffic detection equipment of the intersection and the variable lane indication board are connected into the annunciator, the traffic is carried out according to the lanes of the intersection provided with the variable lane entrance way, the values of a, b and m in the threshold value model are input, and a trigger statement is arranged in the annunciator to realize automatic switching of the variable lanes;
s3, adjusting signal timing of a signalized intersection according to traffic running conditions after the lane change; the traffic signal timing is adjusted according to the latest traffic running condition, so that the traffic signal timing is more matched with the latest traffic flow condition;
the ratio of the flow of the intersection after the lane change is:
wherein:
the total flow ratio after the attribute of the variable lane at the entrance of the Y' -signalized intersection is changed;
k-total flow ratio before changing the attribute of the variable lane at the intersection entrance;
yS -a flow ratio of the straight-going phase before the variable lane property becomes straight-going;
yL -flow ratio of left turn phase before variable lane properties become straight;
according to the Webster model, the signal timing period is:
the effective green time of the left-turning phase of the entrance road after the attribute of the variable lane of the entrance road of the signalized intersection is changed is as follows:
when the attribute of the variable lane of the entrance lane of the signalized intersection is changed, the effective green time of the straight-going phase of the entrance lane is as follows:
the effective green time of other phases after the attribute of the variable lane of the entrance lane of the signalized intersection is changed is as follows:
wherein:
yi -the other phase, the original flow ratio, when the properties of the variable lanes of the signalized intersection entrance are changed.
S4, simulating and implementing the scheme by using traffic simulation software, performing effect tracking evaluation by data comparison analysis, and optimizing the scheme according to an evaluation result; the signal timing adjustment model is suitable for the situation that the single steering traffic flow is oversaturated after the variable lane of the intersection is switched, namely, the overflow situation of the variable lane or the oversaturation phenomenon of the traffic flow in the direction of reducing the lane after the variable lane is switched, if the oversaturation situation of the left-turn and straight-going phase traffic flow is both generated after the variable lane is switched, the change of the attribute of the variable lane at the entrance of the signal intersection is not obvious for improving the traffic jam situation at the entrance of the road signal intersection, and under the situation, redesign and optimization are needed for the signal intersection.
In order to simplify the operation result, the scene is that the variable lane is switched from a left-turning lane to a straight-turning lane, and the threshold model for changing the variable lane from the straight-turning lane to the left-turning lane or other changing forms and the signal timing adjustment model are the same.
The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and to implement the same, but are not intended to limit the scope of the present invention, and all equivalent changes or modifications made according to the spirit of the present invention should be included in the scope of the present invention.