RU2379761C1 - Method of controlling road traffic at intersection - Google Patents

Abstract

FIELD: physics; signaling.

SUBSTANCE: invention relates to controlling road traffic and specifically to controlling road traffic at an intersection. The method involves setting the time for switching the traffic light signal on the given direction of motion proportional to the length Δ of the road section, occupied by vehicles from the boundary line of the intersection to the final boundary of the road section, occupied by the vehicle on that road section, and the number n of vehicles on the given road section taking into account speed of vehicles before the intersection and the time lag before the next vehicle starts moving after the previous vehicle. The time for switching traffic light signals is determined using the expression

where t_sw is time for switching traffic light signals; W is average speed of vehicles before the intersection; τ_pr is average lag time before the next vehicle starts moving after the previous. The greatest value τ_cr for opposite directions of motion on the intersection is selected, and values τ_cr, W and τ_pr are corrected depending on traffic flow conditions and state of the road.

EFFECT: prevention of asymmetrical accumulation of vehicles before a traffic light on an intersection, avoiding unjustified delays and traffic jams at intersections, which reduces stoppages of vehicles and combustible and harmful emissions into the atmosphere.

2 cl, 2 dwg

Description

The invention relates to the field of traffic management and, in particular, to regulating the movement of vehicles at the intersection.

Known most commonly used in practice are methods of regulating the movement of vehicles at the intersection [1-3]. In this case, the switching of traffic signals is carried out using a switching relay and a timer with a fixed setting of the switching time of traffic signals. The switching time can be adjusted at the location of the traffic light or remotely.

However, the disadvantage of this method is the installation of a fixed switching time, which does not allow you to monitor the current traffic situation in dynamics (at a pace with the traffic situation) and respond to this situation in a timely manner using the length of the switching time of traffic signals. In turn, this creates asymmetric flows of vehicles on the sides of the road, which leads to unjustified delays in traffic and traffic jams.

There are also known methods and devices of a more complex schedule for regulating traffic flows at intersections.

In this case, vehicle detection detectors are used and the queue length of vehicles in front of a traffic light is taken into account [1-3]. Intelligent systems for modeling traffic control at intersections are also proposed [4, 5].

However, the drawback of these methods and devices is, in one case, the lack of clear recommendations for determining the switching time of a traffic light, and in the other, the complexity of the proposed means of distributing traffic flows, which ultimately does not allow the organization of the work of switching traffic control devices in real time. In the cases of [4, 5], for example, algorithms and software are intended mainly for modeling devices.

A known method and device for automated control of street transport [2]. This takes into account the length of the road section occupied by cars in front of the intersection. However, in this case, when cars are collected in front of the intersection, the distance between the cars at the intersection is not taken into account, i.e. the number of cars in a given section of the road, and thus the delay time at the intersection of the next car after the start of the previous one is not taken into account, i.e. the real time of the pure (transport) delay, which does not allow us to really assess the required switching time of traffic signals.

The technical task of the present invention is to provide reliable information about the time delay when passing vehicles along the length of the road section occupied by vehicles, for a more accurate assessment of the necessary switching time of traffic signals and thereby more efficient control of traffic at the intersection, reduction of vehicle downtime, reduction of fuel consumption and harmful emissions into the atmosphere.

This task is achieved by the fact that the method of regulating the movement of vehicles at the intersection includes traffic control using a traffic light, switching traffic signals using switching relays and a timer, determining the length of the road section occupied by cars from the boundary line of the intersection to the final border of the road section occupied by cars on this road section, characterized in that the time of switching traffic signals from green to red is set taking into account the determination of the average p Normal distance between the cars before the intersection, that is, the number of cars in a given section of the road, and taking into account the delay time at the intersection of the next car after the start of the previous car, the time of switching traffic signals from green to red t _pep is determined simultaneously for oncoming lanes at the intersection from the expression

where t _mouth is the base time of the installation of switching traffic signals for the normal mode of movement (without congestion of cars in front of the traffic light);

Δ is the length of the road section occupied by cars; W is the average speed of vehicles at the intersection; n is the number of cars in front of a traffic light;

τ _Tr - the average delay time of the beginning of the movement of the next car after the start of the previous one, after which the switching time of the traffic signals for opposite sides of the movement of cars is compared and the highest of these compared values is set at the traffic light t _pe = max t _pe .

The method also differs in that in the case of the presence of two or more lanes before the intersection, the switching time of traffic signals is selected as the largest of these for these compared values.

It is known what difficulties with automatic regulation arise if there is a time of pure (transport) delay in the regulated object. In this case, it is necessary to have accurate information about this time for the synthesis of the regulation system and the estimation of the regulation time by processes [5].

In this invention, to clarify this time, the net lag is taken into account in the difficult situation of road traffic (when cars are accumulating in front of the intersection) not only the length of the road section Δ occupied by the cars, but also the average distance between cars and the number of cars in front of the intersection, since the time of the net traffic lag of this cluster of cars before the intersection is determined not only by the speed of the cars after the green light of the traffic light is established, but also by the steady distance between the cars, as well as a certain time delay the inevitable movement (breakaway), followed by the car after driving in front of parked cars (the start time of starting the machine) T _tr. The average distance between cars along the length Δ is determined by the number of cars n, and the additional time with a delay of movement τ _{app is} determined as

In this case, the total time of net delay t _{zap of} finding this queue of cars before the intersection is defined as

where Δ is the length of the road occupied by vehicles (the largest of the oncoming lanes); W is the average speed of vehicles at the intersection.

The present invention for organization of smooth operation at the intersection traffic regulation is proposed to introduce a pure time delay t as the correction _zap to a certain time (baseline) time t installation _mouth switching traffic signal for normal traffic, i.e. time set without traffic congestion in front of a traffic light. In this case, if there is a base time setting, even in the event of an unforeseen failure to determine the net delay time t _app , the motion control will not be completely blocked. In this invention, the values of t _mouth , W, t _zap are adjustable _settings , since their values depend on the specific situation on a given section of the road (for example, ice, wet roads, rough roads, etc.). The values Δ and n when using sensors (detectors) of observation are determined using pattern recognition methods [7].

In the proposed method, the required switching time t _per is determined simultaneously for oncoming lanes at the intersection and these determined times are compared with the choice of the largest of them for switching signals at the traffic light, i.e. with a choice of value

If there are two or more lanes at the intersection, the time for switching traffic signals at the highest value for these lanes is selected.

In the case of the arrows at the traffic lights turning turns (to the right, to the left), the switching time of traffic signals is additionally determined for a given lane of vehicles.

In the present invention, the installation time of switching traffic signals for the normal mode of traffic, the average speed of vehicles at the intersection, the average delay time of the start of movement of the next car after the start of the previous one are correction values when determining the time of switching traffic signals, are estimated and set by operators depending on the conditions of the situation traffic in front of the intersection.

Thus, in the event of a congestion of cars before the intersection, the switching time increases by the real time of the net delay, which contributes to the rapid evacuation of cars on the side of the road overloaded with traffic in front of the intersection, prevents further accumulation of vehicles and the formation of traffic jams.

The method is implemented by the device shown in Figs. 1 and 2. It includes (Fig. 1) a traffic light 1, a sensor for monitoring road sections in front of traffic lights in perpendicular (or required) directions 2; traffic light unit with sensors (detectors) of observation 3; a line for transmitting the readings of the observation sensors to the processing signal receiver 4; traffic light control point 5; central axis of sight of the observation sensors 6; lines for recording the results of sighting of observation sensors 7; sections of road occupied by cars 8; scanning device for monitoring sensors 9.

Figure 2 presents a block diagram of a device for implementing the method. The device includes: traffic light 1; observation sensor (detector) 2; traffic light unit with observation sensors 3; signal transmission lines from observation sensors 4 to the processing signal receiver 5; a unit for recognizing the length of the largest stretch of road occupied by vehicles in a given direction, and the number of cars in a given stretch of road 6; computing unit 7; adjustment block: the base time for switching traffic signals (in the absence of traffic congestion in front of the intersection), the average vehicle speed at the intersection, and the delay time for the next vehicle to start moving after the previous 8 starts moving; a unit for setting the estimated time for switching traffic signals 9; timer 10; switching relay 11 and the block scanning sensors of observation 12.

The device operates as follows. At traffic light 1 (Figs. 1 and 2) using a timer 10 (Fig. 2), the base time for switching traffic signals t _{yst is set} (see formula (1)), while relay 11 (Fig. 2) provides switching of traffic signals. Observation sensors 2 (FIGS. 1 and 2) provide sighting on road sections in front of a traffic light and transmitting an image of a road section with cars located on it along transmission lines 4 to a processing signal receiver 5 (FIG. 2). Using block 6 (Fig. 2), in which the pattern recognition program is used, the length of the road section 8 (Fig. 1) occupied by vehicles from the boundary line in front of the intersection to the final border of the road section occupied by Δ vehicles is determined, the largest for this direction of movement , and the number of cars on this section of the road. In the computing unit 7 (Fig. 2), the time for switching traffic signals from green to red according to formula (1) is determined for each of the opposite directions of movement, while the coefficients t _mouth , W, τ _tr are set and can be adjusted if necessary by the correction unit 8 (figure 2). The computing unit also compares the determined switching times t _per for opposite directions of traffic at the intersection with the choice to use the highest value t _per = max t _per . The switching time of the traffic signals calculated and selected in block 7 t _per = max t _per (see formula (1)) is used in block 9 to adjust the timer 10, which switches traffic signals 1 using relay 11 in accordance with the adjusted switching time. In the proposed method, various types of their execution (at the manufacturer’s choice) are used as sensors 3 (FIGS. 1 and 2) and a processing signal receiver 5 (FIG. 2): sighting heads of television installations and a television receiver; infrared sensors and related receivers; radiators of radio waves and radios. In case of need to change the central axis of sight of the sensors 6 and the corresponding line of viewing angles of the sensors 7 (Fig. 1), use a scanning device 9 (Fig. 1), 12 (Fig. 2).

Method implementation examples

Example 1. In block 8 (Fig. 2), the base time for switching traffic signals t _set = 10 s is established (see formula (1)).

Using observation sensors 2, transmission lines 4, and a processing device 5, the distance from the boundary line in front of the traffic light to the final boundary of the section of the road occupied by cars in the lane of one direction of road 8 (the left part of Fig. 1) is determined Δ = 30 m and the number of cars n = 12, and for the opposite direction of the road Δ = 20 m and n = 10. In block 8 (FIG. 2), the parameters are set in formula (1) t _mouth = 10 s, W = 20 m / s and τ _tr = 2 s. In block 7 (FIG. 2), the required time is calculated by formula (1) switching traffic signals from green to red for both directions

In block 7, these values are compared and the largest value is selected from them t _per.1 > t _nep.2

t _per. 1 = max t _per = 33.5 s.

Using the unit for setting the estimated switching time of traffic signals 9 (Fig. 2), the switching time of traffic signals for this switching half-time is set in the timer 10 t _per = 33.5 s, which is realized using relay 11 (Fig. 2). After switching the traffic light signal in the next half-period of the traffic light operation, the sequence of the above device actions is repeated, but already for the road lane, perpendicular to the lane considered in the previous switching half-period.

From this example it follows that the duration of the adjusted switching time of the traffic light depends to a large extent on the delay time of starting the cars after the start of the movement of the previous car, which is provided in this method.

Example 2. The basic switching time is the same as in example 1 t _mouth = 10 s, as well as the same values Δ = 30 m and n = 12 and Δ = 20 m and n = 10 m. Due to the presence of ice and fog speed of the vehicle at the intersection is reduced to 10 m / s, and the delay time τ _Tr increased to 2.5 s.

In this case

In this case, the switching time of traffic signals increases compared to example 1 and equals

t _lane = max t _lane = 40.5 s.

Example 3. The basic switching time is the same as in example 1 t _set = 10 s. Using the observation sensor 2, transmission lines 4 and a processing device (Figs. 1, 2), the presence of transport on road sections from the boundary line before the intersection in two opposite directions of traffic has not been established. In this case, Δ = 0 and according to the formula (1) is determined in block 7 (Fig. 2) the switching time t _per equal to the basic switching time

t _lane 1 = t _{lane 2} = t _lane = t _mouth · 0.3 · 0 = 10 s.

The use of this method and device provides accelerated evacuation of vehicles from the lane most overloaded with vehicles, which prevents the formation of large accumulations of vehicles and the formation of unjustified traffic jams. This reduces the fuel consumption of cars and the emission of harmful emissions on road sections in front of intersections.

BIBLIOGRAPHIC SOURCES

1. Pechersky M.P., Khorovich B.G. Automated traffic control systems in cities. - M .: Transport, 1979. - 176.

2. Artykov A.P. Automation of street passenger transport management in large cities abroad. - M.: GOSINGI, 1975 .-- 39 p.

3. Rushevsky P.V. Organization and regulation of traffic using automatic controls. - M .: Higher school. 1974.- 238 p.

4. Grigoriev D.A., Shaimardanova S.I., Balyklov T.S. Certificate of official registration of the computer program "Neural network traffic flow control system at intersections of arbitrary configuration" No. 2002611009 of June 20, 2002, Rospatent, Moscow.

5. Yusupova N.I., Bazhin D.N. Models and algorithms of transport flow control based on fuzzy logic // Russian Scientific and Methodological Conference with international participation "Economics Management: Methods, Models, Technologies". Sat scientific works in 3 parts. Part 2. Ufa: USATU, 2001. S.19-24.

Claims (2)

1. A method of regulating the movement of vehicles at an intersection, including controlling traffic using a traffic light, switching traffic signals using switching relays and a timer, determining the length of a section of a road occupied by cars from the boundary line in front of the intersection to the end of the section of the road occupied by cars on a given section of the road characterized in that the time for switching the traffic light from green to red is set taking into account the determination of the average distance between cars before ekrestkom and the number of vehicles on the road segment, as well as the delay time at the crossroads subsequent vehicle movement after the beginning of the movement of the previous machine, the switching time of traffic lights from green to red light is determined at a time t _lane for oncoming traffic lanes at the crossroads of expression

,
where t _mouth - the base setup time for switching traffic signals for the normal mode of movement without congestion in front of the traffic light;
Δ is the length of the road section occupied by cars;
W is the average speed of vehicles at the intersection;
n is the number of cars in front of the intersection;
τ _Tr - the average delay time of the beginning of the movement of the subsequent machine after the start of the previous movement,
then compare the switching time of traffic signals for opposite sides of the movement of vehicles and set at the traffic light the largest of these compared values t _lane = max t _lane . 2. The method according to claim 1, characterized in that in the case of the presence of two or more lanes before the intersection, the switching time of traffic signals is selected as the largest of those defined for these lanes.

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