CN105608913A - Handheld device for urban road intersection signal control - Google Patents

Abstract

The invention provides a handheld device for signal control of an urban road intersection. The invention sends the state of the signal controller and the detection information to the handheld device in real time through the wireless network for the urban road intersection provided with the traffic information detector. A traffic state evaluation algorithm is built in the handheld device, the quality of signal control can be evaluated on line, meanwhile, the optimization of a signal control timing scheme is realized by utilizing real-time traffic flow detection data and an on-line evaluation result, and the traffic signal control algorithm is corrected according to the special traffic condition on site. By adopting the method, the control efficiency of the urban road intersection can be effectively improved according to the actual situation of the traffic site, and the purpose of relieving congestion is achieved.

Description

A kind of hand-held device for urban road intersection signal controlling

Technical field

The invention belongs to intelligent transport technology field, be specifically related to Real time Adaptive Traffic Control optimisation technique.

Background technology

Current widely used single intersection control mainly comprises timing controlled, induction control and Self Adaptive Control, itsMiddle timing controlled cannot be carried out timing project setting by Real-time Obtaining traffic flow data, and induction is controlled and be adaptiveAlthough should control the traffic flow of energy Real-time Obtaining, be not suitable for using these several controls simultaneously in supersaturation situationSystem is open loop control, and itself cannot be assessed and optimize in time the signal controlling effect at crossing. Even ifSome has realized the crossing of center cluster formula control, also often because the problems such as network cause realizing advanced personControl and effectively assessment. But urban road crossing is as the important component part of urban traffic control, carries on a shoulder poleBear the important function of controlling wagon flow and ensureing traffic safety, therefore rationally using crossing signal control method, andIn time, obtains and controls effect feedback, optimizes in time timing scheme, for alleviating urban traffic blocking, ensureing rowCar has safely extremely important meaning.

Summary of the invention

The deficiency existing in controlling for current crossing, the present invention detects data in conjunction with traffic flow to be controlled crossing in real timeEffect processed is assessed, if do not control when effect meets expection, signal controlling timing scheme is carried out to rapid Optimum,Simultaneously in conjunction with the decision-making of on-the-spot virtual condition is further revised prioritization scheme. The following technical scheme of concrete employing:For the hand-held device of urban road intersection signal control comprise information gathering and new module more, wireless communication module,Information processing and computing module, information gathering is with more new module is used for telecommunication flow information collection, signal controller is joinedTime scheme information gather and timing scheme renewal, it is sent out the telecommunication flow information collecting by wireless communication moduleGive information processing and computing module; Information processing and computing module are by built-in traffic signals control assessment mouldPiece is controlled effect to current crossing and is assessed, and generates assessment result, and judges whether to need for assessment resultTo be optimized current demand signal timing method by built-in traffic signals control timing module, if needed,Generate new timing scheme; And by wireless transmission method by new timing scheme send to information gathering with moreNew module, is written to new timing scheme in signal controller by information gathering and new module more;

Wherein, the method that traffic signals control evaluation module is assessed current crossing control effect is as follows:

1), according to crossing Real-time Traffic Information, judge the real-time traffic states at crossing:

$\left\{\begin{array}{c}x=max\{x_i,i=1,...,n\}\\ x_i=\frac{q_i\·C}{S_i\·g_i}\end{array}\right.$

Wherein, x_iFor the saturation degree of phase place i; It is intersection saturation degree that x represents to get maximum phase place saturation degree; q_iForPhase place i vehicle flowrate; C is the intersection signal cycle time of original timing scheme; S_iFor the saturated flow of phase place iRate; g_iFor the green time of phase place i;

If x=max{x_i, i=1 ..., n} < 1, judges that crossing is in undersaturated condition;

If x=max{x_i, i=1 ..., n} >=1, judges that crossing is in hypersaturated state;

2) calculating crossing incurs loss through delay and the traffic capacity:

When crossing is during in undersaturated condition, incur loss through delay and traffic capacity computing formula as follows:

$\left\{\begin{array}{c}{d}_{i\left(u\right)}=\frac{1}{2}\&CenterDot;\frac{S_i\&CenterDot;q_i}{S_i-q_i}\&CenterDot;{\&lsqb;(1-\frac{q_i}{\underset{i=1}{\overset{n}{\&Sigma;}}{q}_i})\&CenterDot;(C-L)\&rsqb;}^2\\ {\mathrm{Cap}}_i=S_i\&CenterDot;\frac{q_i}{\underset{i=1}{\overset{n}{\&Sigma;}}{q}_i}\&CenterDot;(1-\frac{L}{C})\end{array}\right.$

When crossing is during in hypersaturated state, incur loss through delay and traffic capacity computing formula as follows:

$\left\{\begin{array}{c}{d}_{i\left(o\right)}=\frac{1}{2}\&CenterDot;q_i\&CenterDot;C^2-\frac{1}{2}\&CenterDot;S_i\&CenterDot;{\&lsqb;\frac{q_i}{\underset{i=1}{\overset{n}{\&Sigma;}}{q}_i}\&CenterDot;(C-L)\&rsqb;}^2\\ {\mathrm{Cap}}_i=S_i\&CenterDot;\frac{q_i}{\underset{i=1}{\overset{n}{\&Sigma;}}{q}_i}\&CenterDot;(1-\frac{L}{C})\end{array}\right.$

Wherein, d_i(u)The phase place i delay time at stop during for undersaturated condition; d_i(o)For the hypersaturated state phase place i delay time at stop;Cap_iFor the traffic capacity of crossing; L is the delay time at stop of crossing;

3) assess intersection signal control effect under original timing scheme:

$\left\{\begin{array}{c}P=\frac{d_i\left(C\right)}{\stackrel{\&OverBar;}{d_i}}=\mathrm{\&alpha;}{d}_{i\left(u\right)}\left(C\right)+(1-\mathrm{\&alpha;})d_{i\left(o\right)}\left(C\right)\\ W=\frac{{\mathrm{Cap}}_i\left(C\right)}{\stackrel{\&OverBar;}{{\mathrm{Cap}}_i}}=Ca{p}_i\end{array}\right.$

Constraints:

Wherein, P is delay ratio; W is traffic capacity ratio;For (design crossing timing is incured loss through delay in designThe necessity producing when scheme is incured loss through delay);By design capacity (is produced when design crossing timing schemeThe raw necessary traffic capacity); Wherein, d_i(C) delay time at stop of phase place i when the expression signal controlling cycle is C;d_i(u)(C) delay time at stop of phase place i under undersaturated condition when the expression signal controlling cycle is C; d_i(O)(C) representThe delay time at stop of phase place i under hypersaturated state when the signal controlling cycle is C; α is weight coefficient; Cap_i(C) tableShow the traffic capacity of phase place i when the signal controlling cycle is C;

If [P < 1, W < 1] or [P > 1, W < 1] or [P < 1, W > 1], now judge that crossing timing needs to optimize;

If [P >=1, W >=1], now judges that crossing timing does not need to optimize.

Preferably, if judge that crossing timing needs to optimize, adopt following optimal way:

Set up signal controlling cycle optimization aim function:

$J=min\left\{\frac{\underset{i=1}{\overset{n}{\&Sigma;}}\left(d_i\right(c)-\underset{d_i}{\arg \min }f(d_i\left(c\right)\left)\right)\&CenterDot;{\left({\mathrm{Cap}}_i\right(c)-\underset{{\mathrm{Cap}}_i}{\arg \min }f({\mathrm{Cap}}_i\left(c\right)\left)\right)}^2}{\sqrt{\underset{i=1}{\overset{n}{\&Sigma;}}{\left(d_i\right(c)-\underset{d_i}{\arg \min }f(d_i\left(c\right)\left)\right)}^2\&CenterDot;\underset{i=1}{\overset{n}{\&Sigma;}}{\left({\mathrm{Cap}}_i\right(c)-\underset{{\mathrm{Cap}}_i}{\arg \min }f({\mathrm{Cap}}_i\left(c\right)\left)\right)}^2}}\right\}$

Constraints is: c_min≤c≤c_max；

Wherein, f (d_i(c) gradient that while) being c for the signal controlling cycle, phase place i incurs loss through delay, f (Cap_i(c)) be signal controllingThe gradient of phase place i traffic capacity when cycle is c;

J is made as to object function, function variable is normalized, adopt genetic algorithm to be optimized and calculateTo the optimum signal controlling cycle;

Generate crossing and optimize timing scheme:

By the signal controlling cycle c calculating after optimization, generate timing according to the traffic flow data of real-time detectionScheme, the green time being optimized:

$g_i^{\&prime;}=q_i(c-L)/\underset{i=1}{\overset{n}{\&Sigma;}}{q}_i$

Its g_min≤g′_i≤g_max，g_minAnd g_maxFor minimum green time and the maximum green time of phase place.

Preferably, information processing and computing module carry out pretreatment to the data that collect, and traffic detector is adoptedThe data of collection are filtered, and remove illegal, invalid data, and effective, legal data are carried out according to standardFormat is processed, and data after treatment are stored.

Preferably, the simultaneously Radio Transmission Technology such as compatible Wifi, 3G/4G of wireless communication module; Information processingWith computing module be the client software based on Android or IOS operating system.

Preferably, in the time of crossing phase place generation overflow or traffic accident, the signal controlling cycle is set to thisThe maximum cycle value of phase place.

The present invention has following useful technique effect:

(1) function advanced person, convenient and practical, and the signal controlling that can realize fast urban road crossing evaluates and optimizes.

(2) add decision-making in-situ function, realize double optimization, avoid due to burst or often the property sent out traffic congestion bringSignal controlling Problem of Failure.

Brief description of the drawings

Fig. 1 is that the present invention assesses optimization timing scheme schematic diagram.

Fig. 2 is signal transmission schematic diagram of the present invention.

Detailed description of the invention

1---information gathering and more new module (being arranged on signal cage inside);

2---radio antenna (being arranged on semaphore compartment top end);

3---information processing and computing module (being arranged on the handheld device of Android/IOS operating system)

In Fig. 1, information gathering and more new module obtain crossing by read signal machine self protocol information and detectTraffic flow data (vehicle flowrate, time occupancy and automobile's instant velocity etc.) and signal controlling that device detects are currentTiming scheme information, sends to information processing and computing module by wireless (Wifi, 3G/4G etc.) mode.Information processing in handheld device and computing module carry out pretreatment to the data that collect, and are mainly traffic is examinedSurvey the data of device collection and filter, remove illegal, invalid data, by effective, legal data according to markStandard formats processing, and data after treatment are stored. And the data that collect are carried out to pretreatment,Be mainly that the data of traffic detector collection are filtered, remove illegal, invalid data, incite somebody to action effectively, closeThe data of method format processing according to standard, and data after treatment are stored. Then, by interiorThe traffic signals control recruitment evaluation algorithm of putting is assessed current control effect, and generates assessment result; SoAfter, current demand signal timing method is entered by built-in traffic signals control timing optimized algorithm for assessment resultRow is optimized, and in conjunction with the field condition closed-loop optimization that circulates, finally generates new timing scheme. Finally, logicalNew timing scheme is sent to information gathering and new module more by wireless (Wifi, the 3G/4G etc.) mode of crossing, byInformation gathering and more new module are written to new timing scheme in signal controller.

Handheld device gathers crossing Real-time Traffic Information, judges the real-time traffic states at crossing:

$\left\{\begin{array}{c}x=max\{x_i,i=1,...,n\}\\ x_i=\frac{q_i\&CenterDot;C}{S_i\&CenterDot;g_i}\end{array}\right.$

Wherein, x_iFor the saturation degree of phase place i; It is intersection saturation degree that x represents to get maximum phase place saturation degree; q_iForPhase place i vehicle flowrate; C is the intersection signal cycle time of original timing scheme; S_iFor the saturated flow of phase place iRate; g_iFor the green time of phase place i; If x=max{x_i, i=1 ..., n} < 1, judges that crossing is in owingSaturation state; If x=max{x_i, i=1 ..., n} >=1, judges that crossing is in hypersaturated state.

3) calculating crossing incurs loss through delay and the traffic capacity:

When crossing is during in undersaturated condition, incur loss through delay and traffic capacity computing formula as follows:

$\left\{\begin{array}{c}{d}_{i\left(u\right)}=\frac{1}{2}\&CenterDot;\frac{S_i\&CenterDot;q_i}{S_i-q_i}\&CenterDot;{\&lsqb;(1-\frac{q_i}{\underset{i=1}{\overset{n}{\&Sigma;}}{q}_i})\&CenterDot;(C-L)\&rsqb;}^2\\ {\mathrm{Cap}}_i=S_i\&CenterDot;\frac{q_i}{\underset{i=1}{\overset{n}{\&Sigma;}}{q}_i}\&CenterDot;(1-\frac{L}{C})\end{array}\right.$

When crossing is during in hypersaturated state, incur loss through delay and traffic capacity computing formula as follows:

$\left\{\begin{array}{c}{d}_{i\left(o\right)}=\frac{1}{2}\&CenterDot;q_i\&CenterDot;C^2-\frac{1}{2}\&CenterDot;S_i\&CenterDot;{\&lsqb;\frac{q_i}{\underset{i=1}{\overset{n}{\&Sigma;}}{q}_i}\&CenterDot;(C-L)\&rsqb;}^2\\ {\mathrm{Cap}}_i=S_i\&CenterDot;\frac{q_i}{\underset{i=1}{\overset{n}{\&Sigma;}}{q}_i}\&CenterDot;(1-\frac{L}{C})\end{array}\right.$

Wherein, d_i(u)The phase place i delay time at stop during for undersaturated condition; d_i(o)For the hypersaturated state phase place i delay time at stop;Cap_iFor the traffic capacity of crossing; L is the delay time at stop of crossing.

4) assess intersection signal control effect under original timing scheme:

$\left\{\begin{array}{c}P=\frac{d_i\left(C\right)}{\stackrel{\&OverBar;}{d_i}}=\mathrm{\&alpha;}{d}_{i\left(u\right)}\left(C\right)+(1-\mathrm{\&alpha;})d_{i\left(o\right)}\left(C\right)\\ W=\frac{{\mathrm{Cap}}_i\left(C\right)}{\stackrel{\&OverBar;}{{\mathrm{Cap}}_i}}=Ca{p}_i\end{array}\right.$

Constraints:

Wherein, P is delay ratio; W is traffic capacity ratio;For (design crossing timing is incured loss through delay in designThe necessity producing when scheme is incured loss through delay);By design capacity (is produced when design crossing timing schemeThe raw necessary traffic capacity); Wherein, d_i(C) delay time at stop of phase place i when the expression signal controlling cycle is C;d_i(u)(C) delay time at stop of phase place i under undersaturated condition when the expression signal controlling cycle is C; d_i(O)(C) representThe delay time at stop of phase place i under hypersaturated state when the signal controlling cycle is C; α is weight coefficient; Cap_i(C) tableShow the traffic capacity of phase place i when the signal controlling cycle is C;

If [P < 1, W < 1] or [P > 1, W < 1] or [P < 1, W > 1], now judge that crossing timing needs to optimize,Enter step 5);

If [P >=1, W >=1], now judges that crossing timing does not need to optimize, return to step 1);

5) set up signal controlling cycle optimization aim function:

$J=min\left\{\frac{\underset{i=1}{\overset{n}{\&Sigma;}}\left(d_i\right(c)-\underset{d_i}{\arg \min }f(d_i\left(c\right)\left)\right)\&CenterDot;{\left({\mathrm{Cap}}_i\right(c)-\underset{{\mathrm{Cap}}_i}{\arg \min }f({\mathrm{Cap}}_i\left(c\right)\left)\right)}^2}{\sqrt{\underset{i=1}{\overset{n}{\&Sigma;}}{\left(d_i\right(c)-\underset{d_i}{\arg \min }f(d_i\left(c\right)\left)\right)}^2\&CenterDot;\underset{i=1}{\overset{n}{\&Sigma;}}{\left({\mathrm{Cap}}_i\right(c)-\underset{{\mathrm{Cap}}_i}{\arg \min }f({\mathrm{Cap}}_i\left(c\right)\left)\right)}^2}}\right\}$

Constraints is: c_min≤c≤c_max；

Wherein, f (d_i(c) gradient that while) being c for the signal controlling cycle, phase place i incurs loss through delay, f (Cap_i(c)) be signal controllingThe gradient of phase place i traffic capacity when cycle is c; J is made as to object function, function variable is normalizedProcess, adopt genetic algorithm to be optimized the optimum signal controlling cycle that calculates.

6) generate crossing and optimize timing scheme

Step 5) the middle signal controlling cycle c calculating after being optimized, according to the traffic flow data of real-time detectionGenerate timing scheme, the green time being optimized:

$g_i^{\&prime;}=q_i(c-L)/\underset{i=1}{\overset{n}{\&Sigma;}}{q}_i$

Its g_min≤g′_i≤g_max，g_minAnd g_maxFor minimum green time and the maximum green time of phase place.

Decision-making in-situ correction: when crossing phase place generation overflow or while going out special circumstances, the cycle is set toC＝C_max, and make this phase placeMake this direction obtain the longest passing through the time.

In Fig. 2, information gathering and more new module 1 are arranged on signal controller inside and carry out detecting number for traffic flowAccording to the transmission of signal controlling information, and signal controlling timing scheme is upgraded; Radio antenna is arranged on letterNumber controller top is for the transmission of data; Information processing and computing module 3 are arranged on Android/IOS operationIn the handheld device of system, for data processing, recruitment evaluation and timing scheme optimization.

Claims (5)

1. for the hand-held device of urban road intersection signal controlling, it comprise information gathering and new module more,Wireless communication module, information processing and computing module, is characterized in that,

Information gathering gather for telecommunication flow information collection, signal controller timing scheme information with new module more andTiming scheme is upgraded, and it sends to information processing and meter by the telecommunication flow information collecting by wireless communication moduleCalculate module;

Information processing and computing module are controlled effect by built-in traffic signals control evaluation module to current crossingFruit is assessed, and generates assessment result, and judges whether to believe by built-in traffic for assessment resultNumber controlling timing module is optimized current demand signal timing method, if needed, generates new timing scheme;And by wireless transmission method, new timing scheme is sent to information gathering and new module more, by information gathering withMore new module is written to new timing scheme in signal controller;

Wherein, the method that traffic signals control evaluation module is assessed current crossing control effect is as follows:

1), according to crossing Real-time Traffic Information, judge the real-time traffic states at crossing:

$\left\{\begin{array}{c}x=max\{x_i,i=1,...,n\}\\ x_i=\frac{q_i\&CenterDot;C}{S_i\&CenterDot;g_i}\end{array}\right.$

Wherein, x_iFor the saturation degree of phase place i; It is intersection saturation degree that x represents to get maximum phase place saturation degree; q_iForPhase place i vehicle flowrate; C is the intersection signal cycle time of original timing scheme; S_iFor the saturated flow of phase place iRate; g_iFor the green time of phase place i;

If x=max{x_i, i=1 ..., n} < 1, judges that crossing is in undersaturated condition;

If x=max{x_i, i=1 ..., n} >=1, judges that crossing is in hypersaturated state;

2) calculating crossing incurs loss through delay and the traffic capacity:

When crossing is during in undersaturated condition, incur loss through delay and traffic capacity computing formula as follows:

$\left\{\begin{array}{c}{d}_{i\left(u\right)}=\frac{1}{2}\&CenterDot;\frac{S_i\&CenterDot;q_i}{S_i-q_i}\&CenterDot;{\&lsqb;\left(1-\frac{q_i}{\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{q}_i}\right)\&CenterDot;\left(C-L\right)\&rsqb;}^2\\ {\mathrm{Cap}}_i=S_i\&CenterDot;\frac{q_i}{\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{q}_i}\&CenterDot;\left(1-\frac{L}{C}\right)\end{array}\right.$

When crossing is during in hypersaturated state, incur loss through delay and traffic capacity computing formula as follows:

$\left\{\begin{array}{c}{d}_{i\left(o\right)}=\frac{1}{2}\&CenterDot;q_i\&CenterDot;C^2-\frac{1}{2}\&CenterDot;S_i\&CenterDot;{\&lsqb;\frac{q_i}{\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{q}_i}\&CenterDot;\left(C-L\right)\&rsqb;}^2\\ {\mathrm{Cap}}_i=S_i\&CenterDot;\frac{q_i}{\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{q}_i}\&CenterDot;\left(1-\frac{L}{C}\right)\end{array}\right.$

Wherein, d_i(u)The phase place i delay time at stop during for undersaturated condition; d_i(o)For the hypersaturated state phase place i delay time at stop;

Cap_iFor the traffic capacity of crossing; L is the delay time at stop of crossing;

3) assess intersection signal control effect under original timing scheme:

$\left\{\begin{array}{c}P=\frac{d_i\left(C\right)}{\stackrel{\&OverBar;}{d_i}}={\mathrm{\&alpha;d}}_{i\left(u\right)}\left(C\right)+(1-\mathrm{\&alpha;})d_{i\left(o\right)}\left(C\right)\\ W=\frac{{\mathrm{Cap}}_i\left(C\right)}{\stackrel{\&OverBar;}{{\mathrm{Cap}}_i}}={\mathrm{Cap}}_i\end{array}\right.$

Constraints:

Wherein, P is delay ratio; W is traffic capacity ratio;For (design crossing timing is incured loss through delay in designThe necessity producing when scheme is incured loss through delay);By design capacity (is produced when design crossing timing schemeThe raw necessary traffic capacity); Wherein, d_i(C) delay time at stop of phase place i when the expression signal controlling cycle is C;d_i(u)(C) delay time at stop of phase place i under undersaturated condition when the expression signal controlling cycle is C; d_i(O)(C) representThe delay time at stop of phase place i under hypersaturated state when the signal controlling cycle is C; α is weight coefficient; Cap_i(C) tableShow the traffic capacity of phase place i when the signal controlling cycle is C;

If [P < 1, W < 1] or [P > 1, W < 1] or [P < 1, W > 1], now judge that crossing timing needs to optimize;

If [P >=1, W >=1], now judges that crossing timing does not need to optimize.

2. according to the hand-held device for urban road intersection signal controlling as claimed in claim 1, itsBe characterised in that: if judge that crossing timing needs to optimize, adopt following optimal way:

Set up signal controlling cycle optimization aim function:

$J=\min \left\{\frac{\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}\left(d_i\right(c)-\underset{d_i}{\arg \min }f(d_i\left(c\right)\left)\right)\&CenterDot;{\left({\mathrm{Cap}}_i\right(c)-\underset{{\mathrm{Cap}}_i}{\arg \min }f({\mathrm{Cap}}_i\left(c\right)\left)\right)}^2}{\sqrt{\underset{i=1}{\overset{n}{\&Sigma;}}{\left(d_i\right(c)-\underset{d_i}{\arg \min }f(d_i\left(c\right)\left)\right)}^2\&CenterDot;\underset{i=1}{\overset{n}{\&Sigma;}}{\left({\mathrm{Cap}}_i\right(c)-\underset{{\mathrm{Cap}}_i}{\arg \min }f({\mathrm{Cap}}_i\left(c\right)\left)\right)}^2}}\right\}$

Constraints is: c_min≤c≤c_max；

Wherein, f (d_i(c) gradient that while) being c for the signal controlling cycle, phase place i incurs loss through delay, f (Cap_i(c)) be signal controllingThe gradient of phase place i traffic capacity when cycle is c;

J is made as to object function, function variable is normalized, adopt genetic algorithm to be optimized and calculateTo the optimum signal controlling cycle;

Generate crossing and optimize timing scheme:

By the signal controlling cycle c calculating after optimization, generate timing according to the traffic flow data of real-time detectionScheme, the green time being optimized:

$g_i^{\&prime;}=q_i(c-L)/\underset{i=1}{\overset{n}{\&Sigma;}}{q}_i$

Its g_min≤g′_i≤g_max，g_minAnd g_maxFor minimum green time and the maximum green time of phase place.

3. the hand-held device for urban road intersection signal controlling of basis as described in claim 1-2,It is characterized in that, information processing and computing module carry out pretreatment to the data that collect, and traffic detector is adoptedThe data of collection are filtered, and remove illegal, invalid data, and effective, legal data are carried out according to standardFormat is processed, and data after treatment are stored.

4. the hand-held device for urban road intersection signal controlling of basis as described in claim 1-3,It is characterized in that the Radio Transmission Technologys such as wireless communication module energy while compatible Wifi, 3G/4G; Information processingWith computing module be the client software based on Android or IOS operating system.

5. the hand-held device for urban road intersection signal controlling of basis as described in claim 1-4,It is characterized in that, in the time of crossing phase place generation overflow or traffic accident, the signal controlling cycle is set to thisThe maximum cycle value of phase place.