CN102289943A - Traffic control method for ensuring smoothness of fly-over crossing - Google Patents

Abstract

The invention discloses a traffic control method for ensuring the smoothness of a fly-over crossing. The traffic control method comprises the following steps of: (1) establishing a real-time traffic state model of a main line of the fly-over crossing: arranging signal lamps and traffic flow detectors at the enhance and exit of each ramp, wherein the signal lamps and the traffic flow detectors are connected with a signal control server, the fly-over crossing is portioned into N controllable units, N is a natural number, and a fly-over crossing main line section between every two adjacent ramps is determined as a controllable unit; (2) performing adaptive control over an entrance ramp based on a traffic capacity-saturation entrance; and (3) controlling the ramp entrance, wherein the ramp regulating signal period of the entrance ramp of a controllable unit i comprises two phases, i.e., a green light and a red light represent that vehicles are allowed/forbidden to enter the fly-over crossing respectively, and green light time tg and red light time within a time interval [KT, (K+1)t] are determined. The traffic control method has high instantaneity, a good control effect and high adaptability.

Description

A kind of traffic control method that guarantees that overpass is unimpeded

Technical field

The present invention relates to traffic control method, especially a kind of overpass traffic control method.

Background technology

Along with the quickening of urbanization speed, motor vehicle is universal day by day, and people are enjoying the while easily that motor vehicle brings, and also face the puzzlement of traffic congestion.Therefore under the existing road condition, implementing effective traffic control method, rationally use existing means of transportation, give full play to its ability, is one of effective ways of transport solution problem.

After the urban development, congested in traffic, buildings is intensive, and the street is difficult to widen, and the road junction of plane grade separation is caused the obstruction of vehicle and crowded, and can not satisfy people's go off daily demand, therefore can form the layout of layer stereo by building overpass, to improve the speed of a motor vehicle and the traffic capacity, relief of traffic density improves the city road network conevying efficiency.The overhead road of city viaduct has become the important symbol of modern city, is widely used in the heavy traffic location in the urban road.

Urban viaduct Ordinary Rd grade is a city expressway, has continuous stream, high capacity, and traffic characteristicses such as saturated flow, but urban viaduct is in the face of the big flow that continues to increase, expectation unimpeded, low-hanging fruit weakens rapidly, and the congestion in road problem is still severe.So that the middle river in Hangzhou-going up the pool overhead is example, 20.3 kilometers of total lengths, establish 5 interchanges and 25 pairs of ring roads along the line, have a lot of social connections 19 meters, two-way Four-Lane Road, the highest traffic capacity of design section is 2200/hour, but recent data statistics according to vehicle supervision department, daytime, the average vehicle flow of 7:00-19:00 surpassed 3000/hour, and wherein maximum flow can reach 4000/hour during the morning peak, so big flow, allowed overpass can't bear the heavy load, and the travel speed rapid drawdown of wagon flow, therefore the problem of blocking up sternness presses for a kind of effective traffic control method that guarantees that overpass is unimpeded.

One of effective ways that On-ramp Control is blocked up as the alleviation overpass.The principle of On-ramp Control: by regulating the magnitude of traffic flow that Entrance ramp enters overpass, make the traffic flow saturation degree of the main line of overpass be in certain service level, thereby make the state of overpass main line traffic circulation, satisfy the travel requirement of traveler in the best.Go into the ring road control method at present and mainly adopt timing controlled: this class methods adopt fixing control strategy or according to default different control strategy of different periods in a day, belong to the non real-time control method, have certain limitation, adaptability a little less than, control effect general.

Summary of the invention

, control effect relatively poor, adaptability more weak deficiency poor for the real-time that overcomes existing overpass traffic control method the invention provides that a kind of real-time is good, control is respond well, adaptability guarantees the traffic control method that overpass is unimpeded preferably.

The technical solution adopted for the present invention to solve the technical problems is:

A kind of traffic control method that guarantees that overpass is unimpeded, described traffic control method may further comprise the steps:

(1) set up overpass main line real-time traffic states model:

At each ring road inlet and ring road outlet signal lamp, magnitude of traffic flow detecting device are installed, described signal lamp all is connected with signal control server with magnitude of traffic flow detecting device;

Article one, overpass is separated into N controllable by ring road, and N is a natural number, is defined as a controllable, the length Δ in each controllable highway section with the overpass main line highway section between every adjacent two ring roads _i, i=1,2 ..., N, the road traffic delay running status is as controlling object, and the sampling period is T, and after the continuous time discretize, t is the sampling time, t=kT, k=1,2 ..., K, i road section traffic volume flow, traffic density and average velocity is q respectively _i(k), ρ _i(k), v _i(k), its entrance and exit ring road flow is designated as r respectively _i(k), s _i(k)

${\mathrm{\ρ}}_i(k+1)={\mathrm{\ρ}}_i\left(k\right)+\frac{T}{{\mathrm{\Δ}}_i}[q_{i-1}\left(k\right)-q_i\left(k\right)+r_i\left(k\right)-s_i\left(k\right)]$

q _i(k)＝αρ _i(k)v _i(k)+(1-α)[ρ _i+1(k)v _i+1(k)-r _i+1(k)]-s _i(k)

The queue length p of Entrance ramp _i(k) satisfy:

p _i(k+1)＝p _i(k)+T[d _i(k)-r _i(k)]

In the formula, d _i(k) the arrival flow of expression Entrance ramp;

Described r _i(k) constraint condition

$\max \{{\mathrm{\γ}}_{i\min },d_i\left(k\right)-\frac{1}{T}[p_{i\max }-p_i\left(k\right)\left]\right\}\≤r_i\left(k\right)\≤\min \{{\mathrm{\γ}}_{i\max },d_i\left(k\right)+\frac{1}{T}{p}_i\left(k\right)\}$

In the formula, γ _Imax, γ _IminBe respectively the upper lower limit value of the default regulation rate of Entrance ramp, p _ImaxQueueing capacity for Entrance ramp i;

(2) the circle mouth adaptive control process of taking part in Taoism that enters the mouth based on the traffic capacity-saturation degree:

The traffic capacity under the physical condition of overpass controllable i:

C _i＝C ₀×f _CW×f _SW×f _HV

C ₀The expression basic capacity;

f _CW---curb-to-curb width is to the correction factor of the traffic capacity;

f _SW---lateral clearance is to the correction factor of the traffic capacity;

f _HV---the correction factor of the paired traffic capacity of traffic group;

γ (k) represents period [KT, (K+1) T] interior Entrance ramp regulation rate, and its computing formula is

$\mathrm{\γ}\left(k\right)=\left\{\begin{array}{cc}{c}_i\×v/c-q_{i-1}(k-1)& {\mathrm{\ρ}}_i\left(k\right)\≤{\mathrm{\ρ}}_{\mathrm{cr}}\\ {\mathrm{\γ}}_{\min }& {\mathrm{\ρ}}_i\left(k\right)>{\mathrm{\ρ}}_{\mathrm{cr}}\end{array}\right.$

In the formula, v/c is the saturation degree of contiguous controllable, ρ _CrCritical value for traffic density;

(3) On-ramp Control process:

There are two phase places in the ring road conditioning signal cycle of controllable i Entrance ramp, promptly allows vehicle to enter overpass and forbid that vehicle enters overpass and has green light and red light to represent respectively, and base is determined at period [KT, (k+1) T] interior green time t _gWith red time t _r:

$t_g=\frac{3600\×n}{\mathrm{\γ}\left(k\right)}$

$t_r=\frac{C_i-\mathrm{\γ}\left(k\right)}{\mathrm{\γ}\left(k\right)}\×t_g=\frac{[C_i-\mathrm{\γ}\left(k\right)]3600\×n}{\mathrm{\γ}{\left(k\right)}^2}$

N is the vehicle number that allows to enter the overpass main line in this cycle, and n=[ρ _Imax-ρ _i(k)] * Δ _i

Further, in the described step (3), in the whole signal period two phase places alternately during increase yellow time.

Further again, described traffic control method is further comprising the steps of:

(4) coordination of exit ramp near floor level intersection control:

Set exit ramp spill-over judgment criterion q _i(k)-ρ _i(k) * Δ _i-s _i(k-1) 〉=p _Imax(k),, then trigger and coordinate control, increase the green property ratio of near floor level intersection if satisfy; If do not satisfy, then the green property ratio of near floor level intersection returns to virgin state.

Technical conceive of the present invention is: unimpeded with the assurance overpass overall situation is gateway, the overpass through street ring road control method of prerequisite: the overpass main line highway section of forming with every adjacent two ring roads is a control module, detect the telecommunication flow information of the traffic of overpass main line and each ring road in real time by the traffic checkout equipment, obtain the real-time traffic running status of control module, determine real-time Entrance ramp regulation rate by the traffic capacity-saturation-adaptive control, and it is obtained the On-ramp Control scheme as input by default model, and implement to be arranged on the signal lamp of Entrance ramp and shrink door automatically, control enters the vehicle flowrate of overpass main line, and with exit ramp near floor level intersection Collaborative Control, the wagon flow of sailing out of overpass is in time evacuated, make the unimpeded and operational efficiency of the traffic behavior of main line reach the highest.This traffic control system is made up of signal lamp, signal controller, traffic flow detecting device, server etc.

Beneficial effect of the present invention mainly shows: 1, real-time is good, control is respond well, adaptability is better; 2, can not only improve the Vehicle Speed of overpass peak period, increase the volume of traffic of peak period, reduce the delay time at stop of traffic congestion and vehicle ', can significantly reduce traffic hazard and energy savings etc. simultaneously, have the benefit of significant social.

Description of drawings

Fig. 1 is the traffic control system topological diagram.

Wherein, 1---ground buried coil; 2---signal lamp; 3---signal controller; 4---the traffic data server; 5---traffic control center; 6---signal controlling service centre; 7---Entrance ramp; 8---overpass; 9---exit ramp; 10---surface road.

Fig. 2 is the process flow diagram of the unimpeded traffic control method of assurance overpass.

Embodiment

Below in conjunction with accompanying drawing the present invention is further described.

See figures.1.and.2, a kind of traffic control method that guarantees that overpass is unimpeded, described traffic control method may further comprise the steps:

(1) set up overpass main line real-time traffic states model:

At each ring road inlet and ring road outlet signal lamp, magnitude of traffic flow detecting device are installed, described signal lamp all is connected with signal control server with magnitude of traffic flow detecting device;

Article one, overpass is separated into N controllable by ring road, and N is a natural number, is defined as a controllable, the length Δ in each controllable highway section with the overpass main line highway section between every adjacent two ring roads _i, i=1,2 ..., N, the road traffic delay running status is as controlling object, and the sampling period is T, and after the continuous time discretize, t is the sampling time, t=kT, k=1,2 ..., K, i road section traffic volume flow, traffic density and average velocity is q respectively _i(k), ρ _i(k), v _i(k), its entrance and exit ring road flow is designated as r respectively _i(k), s _i(k)

${\mathrm{\ρ}}_i(k+1)={\mathrm{\ρ}}_i\left(k\right)+\frac{T}{{\mathrm{\Δ}}_i}[q_{i-1}\left(k\right)-q_i\left(k\right)+r_i\left(k\right)-s_i\left(k\right)]$

q _i(k)＝αρ _i(k)v _i(k)+(1-α)[ρ _i+1(k)v _i+1(k)-r _i+1(k)]-s _i(k)

The queue length p of Entrance ramp _i(k) satisfy:

p _i(k+1)＝p _i(k)+T[d _i(k)-r _i(k)]

In the formula, d _i(k) the arrival flow of expression Entrance ramp;

Described r _i(k) constraint condition

$\max \{{\mathrm{\γ}}_{i\min },d_i\left(k\right)-\frac{1}{T}[p_{i\max }-p_i\left(k\right)\left]\right\}\≤r_i\left(k\right)\≤\min \{{\mathrm{\γ}}_{i\max },d_i\left(k\right)+\frac{1}{T}{p}_i\left(k\right)\}$

In the formula, γ _Imax, γ _IminBe respectively the upper lower limit value of the default regulation rate of Entrance ramp, p _ImaxQueueing capacity for Entrance ramp i;

(2) the circle mouth adaptive control process of taking part in Taoism that enters the mouth based on the traffic capacity-saturation degree:

The traffic capacity under the physical condition of overpass controllable i:

C _i＝C ₀×f _CW×f _SW×f _HV

C ₀The expression basic capacity;

f _CW---curb-to-curb width is to the correction factor of the traffic capacity;

f _SW---lateral clearance is to the correction factor of the traffic capacity;

f _HV---the correction factor of the paired traffic capacity of traffic group;

γ (k) represents period [KT, (k+1) T] interior Entrance ramp regulation rate, and its computing formula is

$\mathrm{\γ}\left(k\right)=\left\{\begin{array}{cc}{c}_i\×v/c-q_{i-1}(k-1)& {\mathrm{\ρ}}_i\left(k\right)\≤{\mathrm{\ρ}}_{\mathrm{cr}}\\ {\mathrm{\γ}}_{\min }& {\mathrm{\ρ}}_i\left(k\right)>{\mathrm{\ρ}}_{\mathrm{cr}}\end{array}\right.$

In the formula, v/c is the saturation degree of contiguous controllable, ρ _CrCritical value for traffic density;

(3) On-ramp Control process:

There are two phase places in the ring road conditioning signal cycle of controllable i Entrance ramp, promptly allows vehicle to enter overpass and forbid that vehicle enters overpass and has green light and red light to represent respectively, and base is determined at period [KT, (k+1) T] interior green time t _gWith red time t _r:

$t_g=\frac{3600\×n}{\mathrm{\γ}\left(k\right)}$

$t_r=\frac{C_i-\mathrm{\γ}\left(k\right)}{\mathrm{\γ}\left(k\right)}\×t_g=\frac{[C_i-\mathrm{\γ}\left(k\right)]3600\×n}{\mathrm{\γ}{\left(k\right)}^2}$

N is the vehicle number that allows to enter the overpass main line in this cycle, and n=[ρ _Imax-ρ _i(k)] * Δ _i

In the described step (3), in the whole signal period two phase places alternately during increase yellow time.

Described traffic control method is further comprising the steps of: the coordination control of (4) exit ramp near floor level intersection: set exit ramp spill-over judgment criterion q _i(k)-ρ _i(k) * Δ _i-s _i(k-1) 〉=p _Imax(k),, then trigger and coordinate control, increase the green property ratio of near floor level intersection if satisfy; If do not satisfy, then the green property ratio of near floor level intersection returns to virgin state.

In the present embodiment, the modeling of overpass main line real-time traffic states: different with urban highway traffic is: overpass does not have level-crossing, thereby its traffic flow is continuous, the traffic of these characteristics and highway is similar, therefore use for reference the MACK model of freeway traffic model, the overpass traffic flow modes is carried out modeling.

Consider that an overpass is separated into N controllable by ring road, be defined as a controllable, the length Δ in each controllable highway section with the overpass main line highway section between every adjacent two ring roads _i(i=1,2 ..., N), the road traffic delay running status is as controlling object, and the sampling period is T, after the continuous time discretize, t=kT (k=1,2 ..., K) i road section traffic volume flow, traffic density and average velocity q respectively _i(k), ρ _i(k), v _i(k), its entrance and exit ring road flow is designated as r respectively _i(k), s _i(k).

${\mathrm{\ρ}}_i(k+1)={\mathrm{\ρ}}_i\left(k\right)+\frac{T}{{\mathrm{\Δ}}_i}[q_{i-1}\left(k\right)-q_i\left(k\right)+r_i\left(k\right)-s_i\left(k\right)]$

q _i(k)＝αρ _i(k)v _i(k)+(1-α)[ρ _i+1(k)v _i+1(k)-r _i+1(k)]-s _i(k)

For the first and last end of overpass, promptly the situation of i=1 and i=N has

ρ ₁(k+1)＝ρ ₁(k)，v ₁(k+1)＝v[ρ ₁(k)]

The queue length p of Entrance ramp _i(k) satisfy:

p _i(k+1)＝p _i(k)+T[d _i(k)-r _i(k)]

In the formula, d _i(k) the arrival flow of expression Entrance ramp

Above-mentioned state equation, Entrance ramp flow r _i(k) be constrained in Entrance ramp regulation rate γ

γ _imax≥γ _i(k)≥γ _imin

γ _Imax, γ _IminBe respectively the upper lower limit value of the default regulation rate of Entrance ramp.

And the queuing vehicle number of Entrance ramp i can not surpass its queueing capacity p _Imax, promptly

p _i(k)+T[d _i(k)-r _i(k)]≤p _imax

Obvious queue length p _i(k+1) 〉=0 promptly

p _i(k)+T[d _i(k)-r _i(k)]≥0

Put in order r _i(k)≤d _i(k)+p _i(k)/T

R in sum _i(k) constraint condition

$\max \{{\mathrm{\γ}}_{i\min },d_i\left(k\right)-\frac{1}{T}[p_{i\max }-p_i\left(k\right)\left]\right\}\≤r_i\left(k\right)\≤\min \{{\mathrm{\γ}}_{i\max },d_i\left(k\right)+\frac{1}{T}{p}_i\left(k\right)\}$

Based on the traffic capacity-saturation degree Entrance ramp adaptive control: the feature of this control method is that the saturation degree of main line of overpass is as controllable parameter, on the basis that the real-time saturation degree of controlling the contiguous controllable of Entrance ramp is v/c and according to the real-time traffic behavior of controllable, determine the ring road regulation rate, its target is with under the unimpeded prerequisite that guarantees overpass, satisfy the road service level of different periods, satisfy the demand of traveler.

The traffic capacity under the physical condition of overpass controllable i:

C _i＝C ₀×f _CW×f _SW×f _HV

C ₀---basic capacity (pcu/h) is general

T is minimal security time headway (s), and design rate is that the basic capacity of 100km/h, 80km/h, 60km/h is respectively 2200pcu/h/ln, 2000pcu/h/ln, 1800pcu/h/ln;

f _CW---curb-to-curb width is to the correction factor of the traffic capacity;

f _SW---lateral clearance is to the correction factor of the traffic capacity;

f _HV---the correction factor of the paired traffic capacity of traffic group.

γ (k) represents period [KT, (k+1) T] interior Entrance ramp regulation rate, and its computing formula is

$\mathrm{\γ}\left(k\right)=\left\{\begin{array}{cc}{c}_i\×v/c-q_{i-1}(k-1)& {\mathrm{\ρ}}_i\left(k\right)\≤{\mathrm{\ρ}}_{\mathrm{cr}}\\ {\mathrm{\γ}}_{\min }& {\mathrm{\ρ}}_i\left(k\right)>{\mathrm{\ρ}}_{\mathrm{cr}}\end{array}\right.$

ρ _CrCritical value for traffic density.

The On-ramp Control design for scheme: the On-ramp Control scheme comprises design two aspects of the signal timing dial of the adjustment of number of track-lines of Entrance ramp and Entrance ramp.

After the determining of ring road regulation rate, if the traffic flow of main line is tending towards saturated, when regulation rate is less than normal, the vehicle flowrate that allows to enter controllable this moment is less, too much accumulate in ring road for fear of vehicle, the psychology that causes driver's anxiety than high latency easily, therefore to adjust the number of track-lines of Entrance ramp, automatic contraction door by the ring road inlet, close the track in good time, carry out the bicycle road by ring road, also be simultaneously intention in the wagon flow of ground to be entered overhead wagon flow played certain caution and reminding effect: current overhead transport stream is tending towards saturated.Make it consider to select the path of other trip in good time.Otherwise, when the traffic flow of main line hour, when regulation rate was bigger than normal, the vehicle flowrate that allows to enter main line this moment was bigger, therefore opens the track on all ring roads, parallel clearance wagon flow shortens entering the time of controllable, in time overpass main line path resource.

The signal time distributing conception design of controllable i Entrance ramp, there are two phase places in the ring road conditioning signal cycle, promptly allow vehicle to enter overpass and forbid that vehicle enters overpass and has green light and red light to represent respectively, this important parameter of regulation rate based on Entrance ramp, therefore to determine at period [KT, (k+1) T] interior green light and red time.

$t_g=\frac{3600\×n}{\mathrm{\γ}\left(k\right)}$

$t_r=\frac{C_i-\mathrm{\γ}\left(k\right)}{\mathrm{\γ}\left(k\right)}\×t_g=\frac{[C_i-\mathrm{\γ}\left(k\right)]3600\×n}{\mathrm{\γ}{\left(k\right)}^2}$

N is the vehicle number that allows to enter the overpass main line in this cycle, and n=[ρ _Imax-ρ _i(k)] * Δ _i, consider road safety, be difficult for causing the disorder of wagon flow, therefore in the whole signal period two phase places alternately during increase yellow time, be preset as 5 seconds.

4. the coordination of exit ramp near floor level intersection control

As exit ramp flow s _i(k) be in higher level, and in exit ramp queuing spill-over phenomenon, and cause overpass main line interwoven region supersaturation to occur, then need to coordinate control with exit ramp near floor level intersection, suitably increase the green property ratio of all directions in respective inlets road, accelerate the exit ramp wagon flow and sail out of overpass, the waste of null resource when avoiding the overpass road, the operational efficiency of raising main line.

Exit ramp spill-over judgment criterion q _i(k)-ρ _i(k) * Δ _i-s _i(k-1) 〉=p _Imax(k), as if satisfying this criterion, then trigger and coordinate control: the affiliated entrance driveway of the crossing that the exit ramp wagon flow is sailed into, and the phase place of definite this affiliated this entrance driveway, minimum with the mean delay time of this import is the optimal control target, dynamically the green property ratio of adjustment cycle and affiliated phase place.

Claims (3)

1. traffic control method that guarantees that overpass is unimpeded, it is characterized in that: described traffic control method may further comprise the steps:

(1) set up overpass main line real-time traffic states model:

At each ring road inlet and ring road outlet signal lamp, magnitude of traffic flow detecting device are installed, described signal lamp all is connected with signal control server with magnitude of traffic flow detecting device;

Article one, overpass is separated into N controllable by ring road, and N is a natural number, is defined as a controllable, the length Δ in each controllable highway section with the overpass main line highway section between every adjacent two ring roads _i, i=1,2 ..., N, the road traffic delay running status is as controlling object, and the sampling period is T, and after the continuous time discretize, t is the sampling time, t=kT, k=1,2 ..., K, i road section traffic volume flow, traffic density and average velocity is q respectively _i(k), ρ _i(k), v _i(k), its entrance and exit ring road flow is designated as r respectively _i(k), s _i(k)

${\mathrm{\ρ}}_i(k+1)={\mathrm{\ρ}}_i\left(k\right)+\frac{T}{{\mathrm{\Δ}}_i}[q_{i-1}\left(k\right)-q_i\left(k\right)+r_i\left(k\right)-s_i\left(k\right)]$

q _i(k)＝αρ _i(k)v _i(k)+(1-α)[ρ _i+1(k)v _i+1(k)-r _i+1(k)]-s _i(k)

The queue length p of Entrance ramp _i(k) satisfy:

p _i(k+1)＝p _i(k)+T[d _i(k)-r _i(k)]

In the formula, d _i(k) the arrival flow of expression Entrance ramp;

Described r _i(k) constraint condition

$\max \{{\mathrm{\γ}}_{i\min },d_i\left(k\right)-\frac{1}{T}[p_{i\max }-p_i\left(k\right)\left]\right\}\≤r_i\left(k\right)\≤\min \{{\mathrm{\γ}}_{i\max },d_i\left(k\right)+\frac{1}{T}{p}_i\left(k\right)\}$

In the formula, γ _Imax, γ _IminBe respectively the upper lower limit value of the default regulation rate of Entrance ramp, p _ImaxQueueing capacity for Entrance ramp i;

(2) the circle mouth adaptive control process of taking part in Taoism that enters the mouth based on the traffic capacity-saturation degree:

The traffic capacity under the physical condition of overpass controllable i:

C _i＝C ₀×f _CW×f _SW×f _HV

C ₀The expression basic capacity;

f _CW---curb-to-curb width is to the correction factor of the traffic capacity;

f _SW---lateral clearance is to the correction factor of the traffic capacity;

f _HV---the correction factor of the paired traffic capacity of traffic group;

γ (k) represents period [KT, (k+1) T] interior Entrance ramp regulation rate, and its computing formula is

$\mathrm{\γ}\left(k\right)=\left\{\begin{array}{cc}{c}_i\×v/c-q_{i-1}(k-1)& {\mathrm{\ρ}}_i\left(k\right)\≤{\mathrm{\ρ}}_{\mathrm{cr}}\\ {\mathrm{\γ}}_{\min }& {\mathrm{\ρ}}_i\left(k\right)>{\mathrm{\ρ}}_{\mathrm{cr}}\end{array}\right.$

In the formula, v/c is the saturation degree of contiguous controllable, ρ _CrCritical value for traffic density;

(3) On-ramp Control process:

There are two phase places in the ring road conditioning signal cycle of controllable i Entrance ramp, promptly allows vehicle to enter overpass and forbid that vehicle enters overpass and has green light and red light to represent respectively, and base is determined at period [KT, (k+1) T] interior green time t _gWith red time t _r:

$t_g=\frac{3600\×n}{\mathrm{\γ}\left(k\right)}$

$t_r=\frac{C_i-\mathrm{\γ}\left(k\right)}{\mathrm{\γ}\left(k\right)}\×t_g=\frac{[C_i-\mathrm{\γ}\left(k\right)]3600\×n}{\mathrm{\γ}{\left(k\right)}^2}$

N is the vehicle number that allows to enter the overpass main line in this cycle, and n=[ρ _Imax-ρ _i(k)] * Δ _i

2. a kind of traffic control method that guarantees that overpass is unimpeded as claimed in claim 1 is characterized in that: in the described step (3), in the whole signal period two phase places alternately during increase yellow time.

3. a kind of traffic control method that guarantees that overpass is unimpeded as claimed in claim 1 or 2, it is characterized in that: described traffic control method is further comprising the steps of:

(4) coordination of exit ramp near floor level intersection control:

Set exit ramp spill-over judgment criterion q _i(k)-ρ _i(k) * Δ _i-s _i(k-1) 〉=p _Imax(k),, then trigger and coordinate control, increase the green property ratio of near floor level intersection if satisfy; If do not satisfy, then the green property ratio of near floor level intersection returns to virgin state.

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