Managing traffic by means of dynamic diversions and virtual queues

Abstract

Road traffic is monitored in a road network 315 leading to a selected destination 303 to obtain from live and historical data an estimate of the rate of arrival of vehicles at the destination, which may be a traffic bottleneck. If the estimated rate exceeds a desired rate, preferably selected to avoid a slow or static queue, vehicles are instructed to diverge from their intended route and may be directed to a waiting area 305. Diverted vehicles are assigned to a virtual queue and are given permission to proceed to destination 303 or elsewhere 304 in accordance with their places in the virtual queue.

Description

[0001] Managing traffic by means of dynamic diversions and virtual queues

[0002] Background to the invention

[0003] As road vehicles travel to destinations, the ability for traffic to flow smoothly often becomes improbable or impossible. This may be due to excess demand for the available road capacity or due to road incidents and road works. This excess demand for available road capacity leads to road congestion and lengthening waiting times or slowly moving traffic.

[0004] Currently, road congestion appears in the form of traffic queues, whereby vehicles are sequentially positioned behind other road vehicles which, in most cases, arrived earlier. This physical queue is how most road queues form and is a basis for most road congestion.

[0005] Physical road queues have major drawbacks as they prevent other road traffic from moving even if not intending to get to the same destination. Severity of the congestion may be compounded if road vehicles can end up with nowhere to go. This has environmental impact as well as social and economic effects. Environmental impacts include an increase in pollution and a deterioration in local air quality caused by stationary vehicles whose engines are running.

[0006] General discussion of preferred features of the invention

[0007] Virtual queues and dynamic road diversions to cater for the virtual queues offer a means to reduce the implications of the physical queue whilst maintaining a preferred rate of arrivals at the intended destination. Overall, this means that total flow rate and vehicles able to get to their destinations need not be adversely affected but the vehicles that would constitute the physical queue can be shifted to a more convenient location away from the road network. For example, while the virtual queue is in progress, vehicles can wait in parked locations elsewhere or depart later for the destination.

[0008] A preferred feature of the invention is the determination of a preferred rate of arrival of vehicles at a particular controlled location, which may be an intermediate stage or a final destination and the estimation from monitoring traffic at an earlier point or points in the road network of the expected rate of arrival at the controlled location. If the expected rate shows an excess over the desired rate, the system will direct that vehicles be diverted from their route to the controlled location.. A virtual queue will include these vehicles and be under control of a virtual queue scheduler which determines when vehicles may be allowed to proceed (for example from a waiting area) to the controlled location or perhaps be directed to a different destination. The preferred rate of arrival is preferably sufficient to avoid a slow or static queue.

[0009] The system preferably includes driver-facing software, traffic management facing software, a traffic arrival system, a routing engine and a collection of live and historical data. The ‘driver-facing’ software may be adapted for autonomous or self-driving vehicles.

[0010] The driver-facing software may be displayed via a hardware device or smartphone running an application that provides instructions for the driver. These instructions are preferably a set of physical actions to take to follow a diversion or to proceed (subject to the virtual queue) to the controlled location.

[0011] The instructions preferably include navigation instructions, in-vehicle messages and alerts (“IVS”) and supporting information such as weather, queue times, expected arrival times and variation analysis.

[0012] The traffic management software preferably includes facilities to create strategic plans and road scenarios that can be used to manage the virtual queue and to determine where the vehicles will physically wait as they progress through the virtual queue. The routes on the road network that vehicles will take can be created on the traffic management software.

[0013] Preferably there is a traffic arrival system (“TAS”) i.e., a software system that manages the key bottlenecks in the road network, including the required vehicle arrival rate at the destinations under traffic management. Vehicles may be assigned a place in the virtual queue by means of self-selection ( in response to a message such as “Join queue now”) or via automatic methods, which may include geolocational triggers or triggers operated when starting an application’s navigation system. The virtual queue may be managed by one or more virtual queue schedulers, which predict the traffic arrival rates at various key bottlenecks and final destination. The system may automatically adjust flow rates via statistical models comparing live information to historical information or may be manually adjusted by a human user, setting target vehicle arrival rates.

[0014] As the number of vehicles heading towards and arriving at the controlled location or locations increases, the actual vehicle flow rate may approach the set flow rates or expected maximum flow rate. Accordingly, a virtual queue scheduler may start to allocate the subsequent required arrival times for vehicles traveling towards the controlled location or locations and thereby require them to be dynamically diverted to different routes or temporary waiting locations.

[0015] The driver-facing application will alert the driver to the dynamic diversion to a waiting area, which could be a car park, service area, truck stop or other location capable of holding a vehicle for a substantial amount of time. The dynamic diversion will direct the driver to this location, even though the driver may have originally had directions set for the actual controlled location. The waiting area allocation may have a driver's preference or be assigned by other criteria such as availability.

[0016] Vehicles may be sequentially held at a waiting area until they are each due to depart. The time of departure may be based on an estimated journey time to the end destination so that the virtual queue scheduler can maintain the desired flow at the destination.

[0017] If road conditions change, further dynamic diversions may be assigned to a vehicle to adjust arrival times based on the virtual queue scheduler. Waiting times at waiting areas may be extended due to a number of factors including required stop and rest times for drivers or for driver preference, such as a longer rest allowing for sleep or preferred arrival time at the controlled location.

[0018] The invention is defined in the claims. There follows a detailed description of a preferred implementation of the invention with reference to the accompanying drawings.

[0019] Brief description of the drawings

[0020] Figure 1 is a schematic drawing of the data processing elements of one form of the invention.

[0021] Figure 2 is a schematic diagram showing how the invention controls traffic in a simple segment of a road network.

[0022] Figure 3 is a schematic diagram showing how the invention controls traffic in a more complex segment of a road network.

[0023] Figures 4 to 7 illustrate the operations of a virtual queue scheduler in various phases.

[0024] Detailed description

[0025] The particular system described can provide the coordination of traffic systems to achieve desired vehicle arrival rates at a controlled location or set of controlled locations. The prediction of arrival is based on collected positional data and historic data with the aim of forecasting if the arrival rate is going to meet a desired volume. The system messages vehicles that have been added to a virtual queue to inform them that they need to follow directional instructions to maintain their position in the virtual queue. Virtual queue scheduler software determines the dynamic diversions and waiting times to achieve a desired traffic rate at a controlled location and adjusts the desired rate having regard to various factors such as weather, road conditions, and the time of year. The adjustment may take into account other forms of potential delay such as industrial action.

[0026] The description that follows is of a system and method for the control of traffic to a geographical location, called herein ’controlled location’, by monitoring the flow of traffic at an earlier location on a route to the controlled location and by means of diverting traffic from the route lessening the probability of a traffic queue at the destination. The system is intended to be particularly applicable to control of commercial traffic in a road network leading to a destination such as a seaport, airport or other location to which there is or can be a heavy flow of traffic. In its basic form the invention needs a measure of the desired rate of flow at the controlled location. How the desired rate is determined is largely a matter of choice and the invention is not limited to any particular process or choice of factors.

[0027] Figure 1 , box 101 denotes a group of stored data, settings and inputs for the virtual traffic queue system. Box 102 denotes the traffic management processes for preparing and organizing the road scenario or strategy. Box 103: denotes a virtual queue system. Box 104 denotes a ‘vehicle-facing’ application, for a human driver as an HMI or a software application for a self-driving vehicle.

[0028] A data store 105 provides stored historical data with relation to the road network, including expected journey times, vehicle journey counts, vehicle types and weather conditions. Data store 106 provides ‘live’ data, which includes vehicle counters, positional data such as GPS tracking of vehicles, camera feeds and derived decisions. A data store 107 provides traffic management settings stored with respect to researched road strategies, road scenarios and system preferences. Data store 108 provides settings with respect to traffic flow rates, flow risk tolerances and traffic reliability. Data store 109 provides settings with respect to destinations, including expected demand, bookings, preferred and optional flow rates.

[0029] The data which is made available from the stores 105 to 109 can be used according to preference to determine two important measures, a desired or optimal flow rate of traffic at a controlled location and a desired flow rate of traffic at an intermediate stage on a route from a source to that controlled location.

[0030] The traffic management system 102 comprises parts 110 to 111. The system 110 determines which road scenario is to be applied and will alter the settings for the virtual queue system such as optional flow rates. System 111 is disposed for managing the road network whereby information or output can be applied to the virtual queue system.

[0031] A virtual queue management system 103 comprises a virtual queue scheduler 112, which will determine the required vehicle arrival rate at the controlled locations (303 and 304) within the entire traffic management system. Virtual queue scheduler 112 manages the expected traffic arrival at one or more locations and manages this expected flow versus the optimal flow rate. If the expected arrival rate is above the optimal flow rate, this virtual queue scheduler 112 will determine which vehicles are to be subject to a virtual queue and diversion.

[0032] The system 103 further comprises an IVS (in-vehicle signage) engine 113, which will create vehicle instructions that vehicles are required to follow to remain while within the virtual traffic queue; and a routing engine 114, which will generate the required navigational directions to vehicles within the virtual traffic queue. These instructions are to be received by either human drivers in their vehicles or by self-driving vehicles.

[0033] Application 115 within each compatible vehicle presents the received directions or navigational information either by way of a human-machine interface for human drivers or by a software application for self-driving vehicles.

[0034] The traffic management system 102 comprises a scenario selector 110 and a traffic decision engine 111. The scenario selector will determine which current road scenario and virtual queue methodology should apply at a given time. The traffic decision engine 111 may be an external system currently used by road traffic management for managing the road network.

[0035] Figure 2 illustrates a simple situation with a single starting point 201 , which could be a starting location or geographical reference point, a single controlled location 202, a single waiting location 203, a single main route 204 from the starting point to the controlled location, a single diversion route 205 from the main route to the waiting location, a single diversion route 206 from the waiting location to the main route, and a traffic flow rate location 207.

[0036] As vehicles travel from starting point 201 to the controlled location 202, the traffic management process 102 will determine which road scenario and road management rules will be implemented, including if the virtual traffic queue will be required. If the traffic queue is required, due to a forecast excess demand above the scenario’s optimal traffic flow at 207, vehicles will be instructed to join a virtual traffic queue and follow instructions to maintain their place in the virtual traffic queue. This may involve following a diversion to a waiting location 203 via path 205. A vehicle subject to the virtual queue will remain at the holding location 203 until the virtual queue scheduler 112 determines it is appropriate for that vehicle to depart towards location 202. The vehicle will then be sent a release message and subsequently follow diversion 206 to rejoin the main route 204 to the location 202.

[0037] Figure 3 illustrates a more complex road layout which comprises two starting locations 301 and 302 for vehicles being monitored for a virtual traffic queue and two possible controlled locations 303 and 304 for vehicles where traffic is sharing part of the same road network. Some vehicles may opt to switch destination based on road conditions or their progress through the virtual traffic queue. In this example there are two locations 305 and 306 where vehicles can wait during their presence in the virtual queue.

[0038] In this example there is a diversion route 307 from a main journey route 315 for taking vehicles to waiting location 305 and a diversion route 308 for returning vehicles to the main journey route from waiting location 305. There is a diversion route 309 from the main journey route for taking vehicles to the waiting location 306 and a diversion route 310 for returning vehicles to the main journey route 315 from the waiting location 306.

[0039] In this example there is a geolocation trigger 311 whereby vehicles can be assigned to the virtual traffic queue based on a geographic reference point rather than on starting points 301 and 302

[0040] Near or at the destination 303 is a geographic reference 312, whereby the traffic arrival rate can be compared to a desired or optimal traffic flow rate.

[0041] Likewise, there is a geographic reference 313 near or at the location 304 whereby the traffic arrival rate can be compared to a desired or optimal traffic flow rate.

[0042] There is also a geographic reference 314 on the main journey route whereby the traffic demand can be compared to desired or optimal traffic flow rate.

[0043] In the road network shown in Figure 3, vehicles will depart from starting points 301 and 302, which could be any number of starting locations or geographic reference points and follow route 315 provided by routing system 114.

[0044] Vehicles may enter the virtual traffic queue as they leave starting points 301 and 302. They may pass a geographic trigger 311 whereby they are caused to join the virtual traffic queue or their position in the virtual traffic queue is adjusted. The traffic management system 102 will determine which road strategy and road scenario are required based on the input data 101.

[0045] At some point during the vehicles’ journey between the starting point (301 or 302) and their destinations (303 or 304) the virtual queue scheduler 112 will determine if the expected traffic flow rates at geographic reference 312, 313 and 314 are above the required or optimal flow rates at those locations and if a virtual traffic queue needs to be applied to vehicles

[0046] If the vehicle is early in the journey and needs to be diverted to a waiting area, the system will determine the most appropriate waiting location (305 or 306) based on vehicle and occupant criteria as well as the current available waiting capacity at the waiting areas. If the vehicle has already passed the easier diversion routes to a waiting area, such as 307 leading to 305, the vehicle will be diverted to a waiting area further along the route such as 306 using diversion 309.

[0047] Vehicles will then wait at their assigned waiting locations (305 or 306) until the virtual queue scheduler determines the most appropriate departure time to ensure the vehicle arrives at the controlled destination (303 or 304) at the required time to maintain the desired traffic flow rates at geographic locations 312, 313 and 314.

[0048] In one embodiment, multiple waiting locations may be used for a single vehicle’s journey.

[0049] Where it is appropriate with vehicle and occupant settings, the routing may alter the end destination for vehicles.

[0050] It is also feasible to delay the departure of vehicles from a starting point whereby to delay their passage to the controlled location.

[0051] Figure 4 illustrates schematically the operation of the scheduling software for a low traffic volume scenario or “free flow". As indicated previously, virtual queue scheduler 401 computes, from inputs of traffic flow along a route, and using both historical date and active date an estimate of the traffic flow (traffic count per unit time) at a controlled location. In Figure 4 the vertical axis 402 represents vehicle count. . A timeline 403 is split into intervals where expected vehicle arrivals can be counted. The vertical bars 404 show expected vehicle arrival rate as counts in respective time intervals. An optimal flow rate, or desired arrival rate, 405 is shown as a corresponding vehicle count per time interval. This is shown as a flat line for simplicity. In practice the desired arrival rate will vary according to the time of the day, the weather and so on.

[0052] In the example of Figure 4, the optimal arrival rate is not exceeded and diversions to vehicles are not required.

[0053] Figure 5 shows a ‘snapshot’ of the virtual queue scheduler wherein the system would forecast a time interval where the expected vehicle arrival rate, represented by the traffic volumes 502 and 503, will exceed the optimal arrival rate 405.

[0054] The vehicles in volume 503 are later in the virtual queue than the vehicles in volume 502. As the vehicles in the 502 have priority, they can proceed to the controlled location whereas the vehicles in the volume 503 will need to be diverted.

[0055] The volume of vehicles 504 have an expected arrival time in the time interval following the vehicles in the volumes 502 and 503. For simplicity we will assume they are later placed in the virtual queue but they may be earlier.

[0056] Diagram 505 is a ‘snapshot’ of the virtual queue scheduler after the volume of vehicles 503 has been diverted sufficiently to move their expected arrival time to the next interval. The volume 503 is now represented by the volume 506.

[0057] There is now in the virtual queue scheduler an expected vehicle arrival rate that shows no instances of exceeding the optimal arrival rate.

[0058] Figure 6 shows several phases of the virtual queue scheduler when there are multiple potential time intervals wherein the expected vehicle arrival rate will exceed the optimal arrival rate 405.

[0059] In the phase denoted 601 , there is in one interval a volume 602 of vehicles with an early place in the virtual queue. In the same interval there is a volume 603 of vehicles that are after the volume 602 in the virtual queue and will be designated for diversion because the combination of the volumes 602 and 603 exceeds the desired arrival rate. There is also a volume 604 of vehicles which are later in the virtual queue than those in volume 603 and have an expected arrival time in the time interval after the one containing volume 602 and 603. There is also volume 605 of vehicles in the virtual queue that are after volume 604 but have an expected arrival time in the same time interval. Finally, there is volume 606 of vehicles that are after volume 605 in the virtual queue but have an expected arrival time in the same time interval.

[0060] The state of the virtual queue scheduler after intervention is made on the volume of vehicles 603 is shown at 607.. These vehicles 603 have been allocated a later arrival time and are shown in position 608. They have been moved to the next time interval so that the expected arrival rate of 602 without 603 does not exceed the optimal threshold 405.

[0061] The vehicles in volume 606 are now shown at 609 and the vehicles in this interval now exceed this time interval’s optimal arrival rate and are sufficiently far back in the virtual queue to require diversion.

[0062] The diagram 610 shows the virtual queue scheduler with the volume of vehicles 609 moved to the next time interval and shown as the volume 611. This time interval includes a further volume of vehicles 612 which are later in the virtual queue and will need further intervention and diversion as the optimal arrival threshold is exceeded.

[0063] This traffic flow shown in Figure 6 is more complex because the optimal arrival rate is expected to be exceeded in more than one time interval and includes the effect of prior diversions.

[0064] Diagram 601 described a first phase of the virtual queue scheduler where the volumes 602 and 603 of vehicles combine to exceed the optimal arrival rate. As volume 602 is earlier in the virtual queue, these vehicles do not need to be diverted.

[0065] Because the vehicles in volume 603 are diverted, their expected arrival interval is then the same as volumes of vehicles 604, 605 and 606. As volume 603 is earlier in the virtual queue, then volume 603 will have priority over the other volumes of vehicles 604, 605 and 606. There is sufficient room for the volumes of vehicles 604 and 605 to remain within this time interval, so no diversion of them will be required. However, the volume 606 is later in the virtual queue and vehicles in this volume will be diverted so that their expected arrival time is later and is shown by the volume 611 in diagram 61O.The vehicles in volume 611 will have priority over the vehicles in volume 612. At least some vehicles in this volume will require diversion later.

[0066] The requirement to create vehicle interventions and diversions can be far more complex but tends to find the next interval where the vehicles have priority in the virtual queue. There may be vehicles with expected arrival intervals later but earlier positions in the virtual queue due to the fact that they are traveling from further away.

[0067] Figure 7 illustrates at 701 the virtual queue scheduler in a state similar to state 601. The vehicles in volume 702 are those which would prefer or require a longer diversion or a rest if they were to be diverted. The diagram 703 shows the queue management system scheduler in a state which would be similar to state 610 except that vehicles in the volume 702 have elected a longer diversion; the arrival time for volume 702 has been delayed to a later time interval as shown by the diagram 704.

[0068] In this last example of the virtual queue scheduler, the process would have followed the phases in diagrams 601 , 607 and 610 but the vehicles in volume 702 allow vehicles behind them in the virtual queue to keep their expected arrival intervals. There may be a need for further interventions and diversions if the expected arrival rate were then to exceed the optimal arrival rate.

[0069] It will be understood that the efficacy of the system is dependent on a substantial proportion of the vehicles in a road system being compatible with the management system.

Claims

Claims1 . A computerised method of controlling the passage of vehicles to a controlled location (202,303, 304), comprising: monitoring the flow of vehicles at a point (311 ) or points on a road network leading to the location; computing on the basis of the said flow an estimated rate of arrival of vehicles at the location; sending instructing messages to at least some vehicles on a route (204, 315) to the location, these messages prescribing a deviation (205, 307, 308) from the said route, when the estimated vehicle arrival rate exceeds a selected limit (405); and establishing at least one virtual queue for vehicles, the virtual queue including places in the queue for vehicles thus diverted and indicating for at least some of those vehicles a delay relative to said route.

2. A method according to claim 1 in which the instructing messages include navigational directions and instructions to maintain a place in and progress through the virtual queue.

3. A method according to claim 1 or 2 and comprising computing from the prevailing traffic conditions a schedule for vehicles to progress to the controlled location; and sending progress or release messages to vehicles in the virtual queue in accordance with the schedule to indicate permission to proceed towards the said location or elsewhere.

4. A method according to claim 3 and controlling the sending of the release messages in accordance with a desired rate of arrival of vehicles at the controlled location.

5. A method according to any foregoing claim and including providing instructions to diverted vehicles to proceed to an alternative location in accordance with their places in the virtual queue.

6. A method according to any of claims 1 to 5 in which the deviation includes a waypoint (305).

7. A method according to claim 6 in which the waypoint (305) is a parking facility.

8. method according to claim 6 or 7 in which there is more than one waypoint and the instructing messages indicate to which waypoint a vehicle is directed.

9. A method according to any of claims 1 to 8 in which there is more than one route to the said controlled location and the method further comprising monitoring the flow of vehicles at a respective stage for each route, and coordinating the sending of the instructing messages in accordance with a desired strategy for the occupation of the waypoints and the rate of arrival of vehicles at the controlled location.

10. A computerised method of controlling the passage of vehicles to a controlled location (202, 303, 304), comprising: monitoring the vehicles for at least one stage (201 , 311 ) in a road network (204, 315) leading to the location; sending instructing messages diverting (205, 307, 308) some of these vehicles whereby to delay their progress to the location; and establishing at least one virtual queue for vehicles, the virtual queue including places in the queue for vehicles thus diverted; allowing diverted vehicles to proceed to the location in accordance with their places in the queue and an estimate of sufficient capacity for traffic at the controlled location; establishing a desired rate of arrival (405) of vehicles at the controlled location; and sending the instructing messages when monitoring of traffic flow in the network indicates that the desired rate is likely to be exceeded.

11. A method according to claim 10 and comprising computing from the prevailing traffic conditions in the network a schedule for vehicles to progress to the controlled location; and sending progress or release messages to vehicles in the virtual queue in accordance with the schedule to indicate permission to proceed towards the said location or elsewhere.

12. A method according to claim 10 or 11 and comprising delaying the departure of vehicles from a departure point whereby to delay their passage to the controlled location13. A method according to any of claims 10 to 12 in which the instructing messages include navigational directions.

14. A method according to any of claims 10 to 13 in which the instructing messages prescribe at least one parking facility.

15. A computerised system arranged and organized to perform a method according to any of claims 1 to 14.

16. A computerised system for controlling the passage of vehicles to a controlled location, the system being organized for: monitoring the flow of vehicles at a point (314) or points on a road network leading to the location; computing on the basis of the said flow an estimated rate of arrival of vehicles at the location; sending instructing messages to at least some vehicles on a route (315) to the destination, these messages prescribing a deviation (307, 308) from the said route , when the estimated rate exceeds a selected limit; and establishing at least one virtual queue for vehicles, the virtual queue including places in the queue for vehicles thus diverted and indicating for at least some of those vehicles a delay relative to said route (315).

17. A system according to claim 15 and disposed for computing from the prevailing traffic conditions a schedule for vehicles to progress to the controlled location; and sending release messages to vehicles in the virtual queue in accordance with the schedule to indicate permission to proceed towards the said location or elsewhere.

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