# Patent

## Title
Solving traffic congestion using vehicle grouping

## Abstract

A method, system, and computer program product for solving a traffic congestion problem are provided in the illustrative embodiments. Using an application executing using a processor and a memory in a data processing system, a congested route section is selected from a set of congested route sections. A set of congesting vehicles is selected, where the set of congesting vehicles cause congestion in the selected congested route sections by being positioned on the selected congested route section. A vacancy data structure corresponding to the selected congested route section is populated. A subset of the set of the congesting vehicles is selected. The subset of the set of the congesting vehicles is rerouted to a candidate route section identified in the vacancy data structure.

## Background
BACKGROUND
1. Technical Field
The present invention relates generally to a method, system, and computer program product for routing traffic. More particularly, the present invention relates to a method, system, and computer program product for solving traffic congestion problems using vehicle grouping.
2. Description of the Related Art
Traffic congestion occurs when the number of vehicles occupying a path exceeds a vehicle capacity of that path. Traffic congestion occurs on land, in air, and on water, and can involve any vehicle designed to travel in those traffic environments.
SUMMARY
The illustrative embodiments provide a method, system, and computer program product for solving traffic congestion using vehicle grouping. An embodiment for solving a traffic congestion problem selects, using an application executing using a processor and a memory in a data processing system, a congested route section from a set of congested route sections. The embodiment selects a set of congesting vehicles, wherein the set of congesting vehicles cause congestion in the selected congested route sections by being positioned on the selected congested route section. The embodiment populates a vacancy data structure corresponding to the selected congested route section. The embodiment selects a subset of the set of the congesting vehicles. The embodiment reroutes the subset of the set of the congesting vehicles to a candidate route section identified in the vacancy data structure.



BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein:
FIG. 1 depicts a pictorial representation of a network of data processing systems in which illustrative embodiments may be implemented;
FIG. 2 depicts a block diagram of a data processing system in which illustrative embodiments may be implemented;
FIG. 3A depicts a block diagram of an example rerouting process that can be improved further using an illustrative embodiment;
FIG. 3B depicts a block diagram of a traffic information processing application that is usable in conjunction with an illustrative embodiment;
FIG. 4 depicts a block diagram of routing on a map grid in which traffic congestion can be removed in accordance with an illustrative embodiment;
FIG. 5 depicts a block diagram of a configuration for solving a traffic congestion problem using vehicle groupings and information sharing in accordance with an illustrative embodiment; and
FIG. 6 depicts a flowchart of an example process of solving a traffic congestion problem using vehicle grouping and information sharing in accordance with an illustrative embodiment.



DETAILED DESCRIPTION
A traffic routing tool is a software application to compute a route for a vehicle. For example, a fleet management application may have a routing component that generates the routes for the fleet vehicles based on the information about the destinations and waypoints the vehicles are to reach. Consider a delivery vehicle as an example. The delivery vehicle's destinations are known based on the deliverables the vehicle is carrying. A set of waypoints are computable from map data to identify the intersections the delivery vehicle has to pass, or turns where the vehicle transitions from one section to the route to another.
As another example, assume the vehicle is an aircraft. Knowing the present location and a destination of the aircraft, a traffic routing tool can compute a route with waypoints along the route, such as intersections, Very High Frequency Omni-directional Range transmitters (VORs), and approach fixes.
When several vehicles occupy a traffic environment, at least some parts of the routes of at least some of the vehicles coincide in time and space. For example, when several vehicles are travelling at the same time in a given part of a town, at least some vehicles are bound to be on the same section of a highway at the same time, but perhaps adjacent to each other and separated by some distance.
A section of a route is portion of the route identified by a beginning point and an endpoint. The beginning and endpoints need not be commonly known or accepted points, but any arbitrary points on a route. Within the scope of the illustrative embodiments, the route can be in any traffic environment, such as on land, in air, or on water. A section of a route can be bound by any two points on the route. Several embodiments are described using surface roads, automobiles, and road maps, only as examples for the clarity of the description and not as a limitation on the illustrative embodiments.
Typically, route sections, such as a road section between two intersections, are designed for predetermined capacity to allow traffic to flow at or above a threshold rate. If more vehicles occupy the section than the capacity, the traffic flow reduces below the threshold rate, causing congestion. The capacity of the section, or an equivalent thereof, exceeding which results in congestion, is called a congestion threshold.
The illustrative embodiments recognize that solving a congestion problem is time consuming and computationally expensive. The illustrative embodiments further recognize that the present methods for solving a congestion problem are wasteful of computing resources for at least two reasons—first, even if the congestion problem requires rerouting of several vehicles away from a congested route section, the present methods attempt to reroute one vehicle at a time. Second, the present methods do not leverage the computations performed in rerouting one vehicle for reducing the computation load of rerouting another vehicle.
The illustrative embodiments used to describe the invention generally address and solve the above-described problems and other problems related to solving congestion problems in traffic routing. The illustrative embodiments provide a method, system, and computer program product for solving traffic congestion using vehicle grouping.
While some embodiments are described with respect to certain numbers of vehicles and route sections, an implementation may use an embodiment to solve for any number of vehicles and route sections without departing the scope of the invention. For example, an implementation of an embodiment may route a set of all vehicles that exceed a route section's capacity together, or in smaller subsets, without departing the scope of the invention. As another example, an implementation of an embodiment can consider not just one route section in the manner described herein, but additional route sections that a vehicle's planned route may be passing through, because congestion generally affects contiguous route sections, within the scope of the illustrative embodiments.
The illustrative embodiments are described with respect to certain traffic environments or vehicles only as examples. Such descriptions are not intended to be limiting on the invention. For example, an illustrative embodiment described with respect to road can be implemented with respect to an aircraft's flight path or a ship's route by using an embodiment.
The illustrative embodiments are described with respect to certain data, data structures, file-systems, file names, directories, and paths only as examples. Such descriptions are not intended to be limiting on the invention. For example, an illustrative embodiment described with respect to a local application name and path can be implemented as an application on a remote path within the scope of the invention. As another example, an embodiment described using a table can be implemented using another data structure within the scope of the illustrative embodiments.
Furthermore, the illustrative embodiments may be implemented with respect to any type of data, data source, or access to a data source over a data network. Any type of data storage device may provide the data to an embodiment of the invention, either locally at a data processing system or over a data network, within the scope of the invention.
The illustrative embodiments are described using specific code, designs, architectures, layouts, schematics, and tools only as examples and are not limiting on the illustrative embodiments. Furthermore, the illustrative embodiments are described in some instances using particular software, tools, and data processing environments only as an example for the clarity of the description. The illustrative embodiments may be used in conjunction with other comparable or similarly purposed structures, systems, applications, or architectures. An illustrative embodiment may be implemented in hardware, software, or a combination thereof.
The examples in this disclosure are used only for the clarity of the description and are not limiting on the illustrative embodiments. Additional data, operations, actions, tasks, activities, and manipulations will be conceivable from this disclosure and the same are contemplated within the scope of the illustrative embodiments.
Any advantages listed herein are only examples and are not intended to be limiting on the illustrative embodiments. Additional or different advantages may be realized by specific illustrative embodiments. Furthermore, a particular illustrative embodiment may have some, all, or none of the advantages listed above.
With reference to the figures and in particular with reference to FIGS. 1 and 2, these figures are example diagrams of data processing environments in which illustrative embodiments may be implemented. FIGS. 1 and 2 are only examples and are not intended to assert or imply any limitation with regard to the environments in which different embodiments may be implemented. A particular implementation may make many modifications to the depicted environments based on the following description.
FIG. 1 depicts a pictorial representation of a network of data processing systems in which illustrative embodiments may be implemented. Data processing environment 100 is a network of computers in which the illustrative embodiments may be implemented. Data processing environment 100 includes network 102. Network 102 is the medium used to provide communications links between various devices and computers connected together within data processing environment 100. Network 102 may include connections, such as wire, wireless communication links, or fiber optic cables. Server 104 and server 106 couple to network 102 along with storage unit 108. Software applications may execute on any computer in data processing environment 100.
In addition, clients 110, 112, and 114 couple to network 102. A data processing system, such as server 104 or 106, or client 110, 112, or 114 may contain data and may have software applications or software tools executing thereon.
Any data processing system, such as server 104, may include traffic routing tool 105 that may be improved using an embodiment. Traffic routing tool 105 may be any suitable software application for computing a route of travel for a vehicle. Application 107 may be any combination of hardware and software usable for implementing an embodiment of the invention such that the embodiment is usable with traffic routing tool 105 for solving congestion problems using vehicle grouping and information sharing. Traffic information processing application 109 in server 106 receives traffic information or information indicative of traffic in a given route section. Traffic information processing application 109 correlates the traffic information with vehicles occupying the route section. Application 107 uses the correlated traffic information together with map data 111 in storage 108 to perform a function according to an embodiment.
Servers 104 and 106, storage unit 108, and clients 110, 112, and 114 may couple to network 102 using wired connections, wireless communication protocols, or other suitable data connectivity. Clients 110, 112, and 114 may be, for example, personal computers or network computers.
In addition, device 118 may be a data processing device associated with a vehicle. Device 118 is able to communicate with network 102 using wireless communication 120. An embodiment can be implemented in device 118. For example, device 118 can include traffic routing tool 105, application 107, traffic information processing application 109, and map data 111 to perform congestion aware rerouting and provide movement information to share with other instances of device 118 in other vehicles in the manner of an embodiment.
In the depicted example, server 104 may provide data, such as boot files, operating system images, and applications to clients 110, 112, and 114. Clients 110, 112, and 114 may be clients to server 104 in this example. Clients 110, 112, 114, or some combination thereof, may include their own data, boot files, operating system images, and applications. Data processing environment 100 may include additional servers, clients, and other devices that are not shown.
In the depicted example, data processing environment 100 may be the Internet. Network 102 may represent a collection of networks and gateways that use the Transmission Control Protocol/Internet Protocol (TCP/IP) and other protocols to communicate with one another. At the heart of the Internet is a backbone of data communication links between major nodes or host computers, including thousands of commercial, governmental, educational, and other computer systems that route data and messages. Of course, data processing environment 100 also may be implemented as a number of different types of networks, such as for example, an intranet, a local area network (LAN), or a wide area network (WAN). FIG. 1 is intended as an example, and not as an architectural limitation for the different illustrative embodiments.
Among other uses, data processing environment 100 may be used for implementing a client-server environment in which the illustrative embodiments may be implemented. A client-server environment enables software applications and data to be distributed across a network such that an application functions by using the interactivity between a client data processing system and a server data processing system. Data processing environment 100 may also employ a service oriented architecture where interoperable software components distributed across a network may be packaged together as coherent business applications.
With reference to FIG. 2, this figure depicts a block diagram of a data processing system in which illustrative embodiments may be implemented. Data processing system 200 is an example of a computer, such as server 104 or client 110 in FIG. 1, in which computer usable program code or instructions implementing the processes of the illustrative embodiments may be located for the illustrative embodiments. Data processing system 200 is also representative of a computing device, such as device 118 in FIG. 1 in which computer usable program code or instructions implementing the processes of the illustrative embodiments may be located for the illustrative embodiments. Data processing system 200 is also representative of an embedded computing device, such as a data processing system embedded in a vehicle in the form of device 118 in FIG. 1, in which computer usable program code or instructions implementing the processes of the illustrative embodiments may be located for the illustrative embodiments. Data processing system 200 is described as a computer only as an example, without being limited thereto. Implementations in the form of device 118 in FIG. 1 may modify data processing system 200 and even eliminate certain depicted components there from without departing from the general description of the operations and functions of data processing system 200 described herein.
In the depicted example, data processing system 200 employs a hub architecture including North Bridge and memory controller hub (NB/MCH) 202 and south bridge and input/output (I/O) controller hub (SB/ICH) 204. Processing unit 206, main memory 208, and graphics processor 210 are coupled to north bridge and memory controller hub (NB/MCH) 202. Processing unit 206 may contain one or more processors and may be implemented using one or more heterogeneous processor systems. Graphics processor 210 may be coupled to the NB/MCH through an accelerated graphics port (AGP) in certain implementations.
In the depicted example, local area network (LAN) adapter 212 is coupled to south bridge and I/O controller hub (SB/ICH) 204. Audio adapter 216, keyboard and mouse adapter 220, modem 222, read only memory (ROM) 224, universal serial bus (USB) and other ports 232, and PCl/PCIe devices 234 are coupled to south bridge and I/O controller hub 204 through bus 238. Hard disk drive (HDD) 226 and CD-ROM 230 are coupled to south bridge and I/O controller hub 204 through bus 240. PCI/PCIe devices may include, for example, Ethernet adapters, add-in cards, and PC cards for notebook computers. PCI uses a card bus controller, while PCIe does not. ROM 224 may be, for example, a flash binary input/output system (BIOS). Hard disk drive 226 and CD-ROM 230 may use, for example, an integrated drive electronics (IDE) or serial advanced technology attachment (SATA) interface. A super I/O (SIO) device 236 may be coupled to south bridge and I/O controller hub (SB/ICH) 204.
An operating system runs on processing unit 206. The operating system coordinates and provides control of various components within data processing system 200 in FIG. 2. The operating system may be a commercially available operating system such as Microsoft® Windows® (Microsoft and Windows are trademarks of Microsoft Corporation in the United States, other countries, or both), or Linux® (Linux is a trademark of Linus Torvalds in the United States, other countries, or both). An object oriented programming system, such as the JavaTM programming system, may run in conjunction with the operating system and provides calls to the operating system from JavaTM programs or applications executing on data processing system 200 (Java and all Java-based trademarks and logos are trademarks or registered trademarks of Oracle and/or its affiliates).
Program instructions for the operating system, the object-oriented programming system, the processes of the illustrative embodiments, and applications or programs, including traffic routing tool 105, application 107, traffic information processing application 109, or a combination thereof, are located on storage devices, such as hard disk drive 226, and may be loaded into a memory, such as, for example, main memory 208, read only memory 224, or one or more peripheral devices, for execution by processing unit 206. Program instructions may also be stored permanently in non-volatile memory and either loaded from there or executed in place. For example, a program code according to an embodiment can be stored in non-volatile memory and loaded from there into DRAM.
The hardware in FIGS. 1-2 may vary depending on the implementation. Other internal hardware or peripheral devices, such as flash memory, equivalent non-volatile memory, or optical disk drives and the like, may be used in addition to or in place of the hardware depicted in FIGS. 1-2. In addition, the processes of the illustrative embodiments may be applied to a multiprocessor data processing system.
In some illustrative examples, data processing system 200 may be a personal digital assistant (PDA), which is generally configured with flash memory to provide non-volatile memory for storing operating system files and/or user-generated data. A bus system may comprise one or more buses, such as a system bus, an I/O bus, and a PCI bus. Of course, the bus system may be implemented using any type of communications fabric or architecture that provides for a transfer of data between different components or devices attached to the fabric or architecture.
A communications unit may include one or more devices used to transmit and receive data, such as a modem or a network adapter. A memory may be, for example, main memory 208 or a cache, such as the cache found in north bridge and memory controller hub 202. A processing unit may include one or more processors or CPUs.
The depicted examples in FIGS. 1-2 and above-described examples are not meant to imply architectural limitations. For example, data processing system 200 also may be a tablet computer, laptop computer, or telephone device in addition to taking the form of a PDA.
With reference to FIG. 3A, this figure depicts a block diagram of an example rerouting process that can be improved further using an illustrative embodiment. Traffic routing tool 304 is an existing traffic routing tool, such as traffic routing tool 105 in FIG. 1, that can be improved to solve traffic congestion problems using vehicle grouping and information sharing according to an embodiment.
Traffic routing tool 304 receives certain aspects of one or more routes in the form of inputs. Map data 306 and vehicle information 307 provides traffic routing tool 304 the information that traffic routing tool 304 needs to perform the routing. Congestion model 308 provides traffic routing tool 304 information about route section capacities, demand on the section, i.e., number of vehicles present on the section, and blockage information, such as obstructions or equipment that cannot be moved from the section. A blockage reduces the true capacity of the route section. Demand of a route section is a measure of existing congestion in the route section by accounting for the capacity, the blockages, and the true capacity of the route section.
Thresholds 310 can be any set of numbers and type of thresholds suitable for a given implementation. For example, in one embodiment, thresholds 310 include a congestion threshold for each route section and a route-length bound for each vehicle. A congestion threshold is a limit on how congested a route section is allowed to become in an acceptable routing solution. For example, a routing specification may require that no route section in a region be congested more than ninety percent for the route computation to be acceptable.
A route-length bound is a limit on the length of a route or route segment. For example, in one embodiment, a route-length bound may specify a scenic ratio constraint, which a critical route should not exceed in an acceptable route computation.
Traffic routing tool 304 delivers an acceptable route in three broad steps. Traffic routing tool 304 constructs an initial Steiner tree using the given map data and vehicle information, such as destinations and waypoints (step 312). Traffic routing tool 304 performs point-to-point routing for the vehicles (step 314). Traffic routing tool performs reroute operations to solve any traffic congestion problems (step 316).
As described earlier, prior art traffic routing tool 304 disadvantageously performs step 316, one congesting vehicle at a time, searching the complete set of potential rerouting solutions for rerouting each congesting vehicle. Presently, traffic routing tool 304 selects a congested route section (step 320). Traffic routing tool 304 select a congesting vehicle on the selected route section (step 322).
Traffic routing tool 304 determines a new route for the congesting vehicle, to wit, finds a new location on the map for positioning the congesting vehicle, (step 324). Prior art traffic routing tool 304 does not reuse any subset of the new route segments, found during a previous iteration of finding a new route, for another congesting vehicle. Accordingly, in determining the new routing of step 324 for a particular congesting vehicle, traffic routing tool 304 performs the determination anew for the congesting vehicle, without the benefit of any similar computations traffic routing tool 304 may have previously performed for another congesting vehicle.
Traffic routing tool 304 determines whether the route section remains congested after rerouting the selected congesting vehicle (step 326). If the route section remains congested, to wit, if more congesting vehicle present on the route section have to be rerouted (“Yes” path of step 326, traffic routing tool 304 returns to step 322 and selects another congesting vehicle for reroute step 316.
If the selected route section is no longer congested, to wit, all congesting vehicles have been rerouted to other route sections (“No” path of step 326), traffic routing tool 304 determines whether more congested route sections remain to be solved in this manner (step 328). If more congested route sections remain (“Yes” path of step 328), traffic routing tool 304 returns to step 320 and selects another congested route section to solve for traffic congestion in this manner.
If no more congested route sections remain (“No” path of step 328), traffic routing tool 304 outputs the revised paths or routes of the vehicles (step 330). Thus, as the illustrative embodiments recognize and solve, prior art traffic routing tool 304 incurs unnecessary computations in generating the reroutes that meets the congestion threshold, route-length bound, and other constraints on the acceptability of a routing solution.
With reference to FIG. 3B, this figure depicts a block diagram of a traffic information processing application that is usable in conjunction with an illustrative embodiment. Application 352 is usable as traffic information processing application 109 in FIG. 1. In one embodiment, application 352 can be included within application 107 in FIG. 1.
Application 352 includes component 354 to receive traffic data from an existing traffic data providing service. For example, component 354 may receive data that informs application 352 that a particular route section is severely congested, moderately congested, or not congested. Such congestion rating of a route section can be translated into values relative to one or more congestion thresholds.
Application 352 includes component 356 to receive data that can be translated to correspond to traffic along a route section. For example, component 356 may receive a volume of cellular voice or data traffic on the base-stations servicing a route section. Generally, the higher the traffic, the higher such volume is likely to be.
Application 352 includes component 358 to receive vehicle identifying data. Component 358 is further configured to correlate traffic data from component 354, data from component 356, or a combination thereof, with the vehicle data to determine which vehicles are present on a route section. For example, a mobile communications provider may deliver not only the volume information but also subscriber information to component 356. Component 358 is configurable to access data that correlates subscribers with vehicles. Accordingly, application 352 can provide vehicles information 307 in FIG. 3A, which is sufficient to learn which vehicles are occupying which route sections, including congested route sections.
With reference to FIG. 4, this figure depicts a block diagram of routing on a map grid in which traffic congestion can be removed in accordance with an illustrative embodiment. Route layout 400 is any suitable depiction of routes of several vehicles, such as by overlaying the routes on a map. Layout 400 includes several blocks as show, each of which is a grid, such as for example, map grid 402. A route section occupies an edge of a grid. An improved traffic routing tool uses layout 400, such as a part of inputs 306 and 307, to produce the revised routes according to an embodiment.
Route section 404 is an example route section that is congested. For example, route section 404 may have a capacity of 10 vehicles, six of which cannot be placed there because of blockages, leaving a true capacity of four for route section 404. As an example, consider that seven vehicles (not shown) are present on route section 404. In this example, assuming a congestion ratio of one hundred percent being acceptable, at least three vehicles out of the seven vehicles have to be rerouted to other route sections in layout 400.
With reference to FIG. 5, this figure depicts a block diagram of a configuration for solving a traffic congestion problem using vehicle groupings and information sharing in accordance with an illustrative embodiment. Layout 500 is analogous to layout 400 in FIG. 4. Grid block 502 is similar to map grid 402, and route section 504 is similar to route section 404 in FIG. 4, respectively. As in the example used to describe FIG. 4, seven vehicles are positioned at route section 504 causing a traffic congestion by at least three vehicles (making at least three vehicles congesting vehicles), depending on the given congestion ratio.
Without implying a limitation thereto, an example manner of denoting a route section's true capacity and available empty tracks (available capacity for additional vehicles) is shown in FIG. 5. Route sections are depicted in layout 500 with their true capacity noted as the top number in the top right corner of the grid block on each route section's left side. Available number of empty tracks for a route section, where a congesting vehicle from another route section can be rerouted, is shown as the second number below that top number. For example, route section 506 has a (true) capacity of three vehicles, and none of the three tracks (0) is available for rerouting a congesting vehicle from another route section. Likewise, route section 508 has a true capacity of 3 with 2 available empty tracks; route section 510 has a true capacity of 3 with 1 available empty track; route section 512 has a true capacity of 3 with 0 available empty tracks; route section 514 has a true capacity of 3 with 1 available empty track; and route section 516 has a true capacity of 3 with 2 available empty tracks.
An improved traffic routing tool according to an embodiment, such as traffic routing tool 304 modified using an embodiment, can use any of route sections 506, 508, 510, 512, 514, or 516 for a modified rerouting of one or more of the congesting vehicles of route section 504. In performing the rerouting of the set of three congesting vehicles of route section 504, the improved traffic routing tool reroutes groups or subsets of the congesting vehicles together. For example, in one embodiment, if route section 508 were to have three tracks available (as different from the depicted availability of 2), the improved traffic routing tool would reroute the set of three congesting vehicles from route section 504 to route section 508 together. In another embodiment, according to the depicted availabilities in route sections 508 and 514, the improved traffic routing tool would reroute a subset of two out of the three congesting vehicles from route section 504 to route section 508 together, and reroute the remaining one congesting vehicle in the set from route section 504 to route section 514.
Having located route section 504 as a congested route section, an embodiment performs an analysis of candidate route sections where some or all of the congesting vehicles of route section 504 can be moved. The embodiment records the results of the analysis in vacancy table 520. In effect, vacancy table 520 is a view of the candidate route sections, which allows the improved traffic routing tool to analyze the vacancy information prior to actual rerouting, and organize the vacancy information such that the information is sharable for rerouting subsets of a set of congesting vehicles.
Vacancy table 520 uses columns 522-528 to store the available track information of route sections neighboring route section 504, such as route sections 506-516, indexed by distance from route section 504. As an example, vacancy table 520 stores index in column 522, distance from route section 504 in column 524, in North direction from route section 504 under column 526, and in South direction from route section 504 under column 528. Directions North and South are used in this example because route section 504 runs North-South and vehicles positioned on route section 504 would have to be rerouted using a route section neighbor to the North or South. In another embodiment, if a congesting vehicle on route section 504 were to be rerouted to the East or West, vacancy table 520 can be adjusted accordingly.
Furthermore, in another embodiment, rerouting in a particular direction can be weighted so that the improved traffic routing tool prefers a higher weighted direction to a lower weighted direction. For example, in one example scenario, a vehicle traveling North may want to continue traveling North after the rerouting instead of taking a scenic detour to the South before proceeding North again. In such a case, a route section to the North of route section 504 may be weighted higher than a route section to the South of route section 504 so that the rerouting selects, if other conditions allow, the section to the North over the section to the South.
In the depicted example, vacancy table 520 has no indexed entry at distance 1 because route sections 506 and 512, which are at distance 1 from route section 504 to the North and to the South respectively, have zero availability and are not candidates for rerouting. At index 0, information about route sections 508 and 514 is indicated, both of which are at distance 2 from route section 504. Route section 508 at distance 2 has an availability of two to the North, and route section 514 at distance 2 has an availability of one to the South. Similarly, at index 1, information about route sections 510 and 516 is indicated, both of which are at distance 3 from route section 504. Route section 510 at distance 3 has an availability of one to the North, and route section 516 at distance 3 has an availability of two to the South.
Additional indices, such as 2, 3, 4, and so on, are not shown in column 522, but if present, would similarly show the information of the candidate route sections farther than distance 3 to the North and to the South from route section 504. If a horizontal route section of grid block 502 were the cause of traffic congestion (not shown), vacancy information of route sections to the East and West of that horizontal route section of grid block 502 would be similarly depicted using a variation of vacancy table 520.
Vacancy table 520 is depicted as a table only as an example, without implying a limitation on the structure for storing similar information. An implementation can use any suitable data structure to store the vacancy information in the depicted manner or another similarly usable manner within the scope of the illustrative embodiments.
Once vacancy table 520 is constructed for a selected route section, such as route section 504, the improved traffic routing tool need not spend computing resources for identifying candidate route sections for rerouting congesting vehicles of route section 504, one congesting vehicle at a time. With the benefit of vacancy table 520, the improved traffic routing tool can identify a subset of congesting vehicles according to some common characteristic, such as a common fleet, common destination or waypoint, similar lengths of routes or detours, similar time constraints (if available, e.g., via device 118 in FIG. 1), similar preferences for rerouting (if available, e.g., via device 118 in FIG. 1), differences between a vehicle's route length and the route-length bound of two congesting vehicles, or any other suitable selection criteria. For example, knowing the difference between the vehicle's route length and route-length bound allows the improved traffic routing tool to limit the rerouting options to only those candidate route sections in vacancy table 520 that are distanced from route section 504 at most by that difference. The improved traffic routing tool can then select a suitable candidate route section and reroute the subset of congesting vehicles together instead of one at a time.
For the remaining congesting vehicles, the improved traffic routing tool need not explore all neighboring route sections for identifying candidate route sections. Vacancy table 520 can be reused, to wit, the information in vacancy table 520 can be shared, for rerouting other congesting vehicles away from route section 504.
Thus, a traffic routing tool improved with an embodiment can solve a traffic congestion problem using vehicle grouping and information sharing. At least for this reason, an improved traffic routing tool according to an embodiment can solve the traffic congestion problem in a more efficient manner as compared to a prior art traffic routing tool.
With reference to FIG. 6, this figure depicts a flowchart of an example process of solving a traffic congestion problem using vehicle grouping and information sharing in accordance with an illustrative embodiment. Process 600 can be implemented as reroute step 316 of traffic routing tool 304 in FIG. 3A to form an improved traffic routing tool according to an embodiment. For example, process 600 can be implemented as application 107 in FIG. 1, and may execute in conjunction with traffic routing tool 105 in FIG. 1.
Process 600 begins by selecting a congested route section from a layout (step 604). Optionally, before performing step 604, an embodiment of process 600 sorts an identified set of congested route sections in the layout (step 602). In one embodiment, process 600 performs the selection of step 604 in the order of highest congestion to lowest congestion according to the sorting of optional step 602.
Process 600 constructs a vacancy list, such as vacancy list 520 in FIG. 5, for a selected route section that is causing the traffic congestion (step 606). Based on one or more selection criteria, process 600 selects a set of vehicles positioned at the congested route section (step 608).
For example, out of the seven example vehicles at route section 504 in FIG. 5, process 600 may select those three to reroute whose route lengths are shorter than a route-length bound by a threshold number of units. Selecting in this manner, process 600 can explore candidate route sections farther from the congested route section of step 604.
The example criterion of the difference between a route length and route-length bound is not intended to be a limitation on the criteria usable for selecting congesting vehicles that should be rerouted. Those of ordinary skill in the art will be able to select congesting vehicles for rerouting using other criteria, such as timing criticality, and such other criteria are contemplated within the scope of the illustrative embodiments.
Process 600 moves (reroutes) a subset of the set of vehicles selected in step 608 according to the vacancy table (step 610). In one embodiment, the subset includes all members of the set. In another embodiment, the subset includes some members of the set. If the subset moved in step 610 leaves some vehicles to be moved in the set, process 600 moves another subset of the set of congesting vehicles in a similar manner using the vacancy table until all vehicles in the set are moved (step 612).
Process 600 determines whether more congested route sections remain to be solved in this manner (step 614). If more congested route sections remain (“Yes” path of step 614), process 600 returns to step 604. If all traffic congestion problems have been solved (“No” path of step 614), process 600 outputs the revised routes for the vehicles (step 616). Process 600 ends thereafter.
The flowchart and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.
Thus, a computer implemented method, system, and computer program product are provided in the illustrative embodiments for solving traffic congestion problems using vehicle grouping and information sharing. Using an embodiment, an improved traffic routing tool can reroute congesting vehicles away from a congested route section in a more efficient manner as compared to a prior art traffic routing tool. The candidate route sections for rerouting are identified and cataloged in a vacancy data structure. The congesting vehicles are selected according to some criteria. A subset of the set of congesting vehicles is selected for rerouting according to certain criteria and rerouted to one or more of the candidate route sections according to the vacancy data structure.
Furthermore, an embodiment can further improve the rerouting process by employing additional operations. For example, congestion usually afflicts contiguous route sections. Therefore, an embodiment can move a congesting vehicle to an empty track in a candidate route section, and then check to determine whether congestion exists in other adjacent route sections. If the embodiment finds congestion in such adjacent route sections, the embodiment can move the vehicle to a farther candidate route section to alleviate congestion in the adjacent route sections as well. For future movements of other congesting vehicles, the embodiment can first check whether a route section adjacent to the congested route section along the section's axis is also has a congested route section. Using this information, the embodiment can choose to move the congesting vehicle farther than the adjacent route section and avoid a contiguous congested region of the layout.
As will be appreciated by one skilled in the art, aspects of the present invention may be embodied as a system, method, or computer program product. Accordingly, aspects of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a “circuit,” “module” or “system.” Furthermore, aspects of the present invention may take the form of a computer program product embodied in one or more computer readable storage device(s) or computer readable media having computer readable program code embodied thereon.
Any combination of one or more computer readable storage device(s) or computer readable media may be utilized. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable storage device may be an electronic, magnetic, optical, electromagnetic, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage device would include the following: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage device may be any tangible device that can store a program for use by or in connection with an instruction execution system, apparatus, or device. The terms “computer-readable storage device,” “computer readable storage device,” and storage device” do not encompass a signal propagation medium such as a copper cable, optical fiber, or wireless transmission medium, any description in this disclosure to the contrary notwithstanding.
Program code embodied on a computer readable storage device or computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.
Computer program code for carrying out operations for aspects of the present invention may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C++ or the like and conventional procedural programming languages, such as the “C” programming language or similar programming languages. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).
Aspects of the present invention are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to one or more processors of one or more general purpose computers, special purpose computers, or other programmable data processing apparatuses to produce a machine, such that the instructions, which execute via the one or more processors of the computers or other programmable data processing apparatuses, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.
These computer program instructions may also be stored in one or more computer readable storage devices or computer readable media that can direct one or more computers, one or more other programmable data processing apparatuses, or one or more other devices to function in a particular manner, such that the instructions stored in the one or more computer readable storage devices or computer readable medium produce an article of manufacture including instructions which implement the function/act specified in the flowchart and/or block diagram block or blocks.
The computer program instructions may also be loaded onto one or more computers, one or more other programmable data processing apparatuses, or one or more other devices to cause a series of operational steps to be performed on the one or more computers, one or more other programmable data processing apparatuses, or one or more other devices to produce a computer implemented process such that the instructions which execute on the one or more computers, one or more other programmable data processing apparatuses, or one or more other devices provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The embodiment was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.

## Claims

1. A computer usable program product comprising a computer readable storage device including computer usable code for solving a traffic congestion problem, the computer usable code comprising:
computer usable code for selecting, using an application executing using a processor and a memory in a data processing system, a congested route section from a set of congested route sections;
computer usable code for selecting a set of congesting vehicles, wherein the set of congesting vehicles causes congestion in the selected congested route sections by being positioned on the selected congested route section;
computer usable code for populating a vacancy data structure corresponding to the selected congested route section, wherein the vacancy data structure stores information about available capacities of a set of candidate route sections, a candidate route section being a route section with available capacity to accommodate a congesting vehicle from the set of congesting vehicles, wherein the information is indexed in the vacancy data structure by a distance between a candidate route section in the set of candidate route sections and the selected congested route section;
computer usable code for selecting a subset of the set of the congesting vehicles; and
computer usable code for rerouting the subset of the set of the congesting vehicles to a selected candidate route section from the vacancy data structure.

2. The computer usable program product of claim 1, wherein the rerouting the subset omits evaluating a possibility of moving a congesting vehicle in the subset to a neighboring route section of the selected congested route section because the neighboring route section is not identified in the vacancy data structure, further comprising:
computer usable code for rerouting a second subset of the set of the congesting vehicles to a second candidate route section identified in the vacancy data structure.

3. The computer usable program product of claim 1, further comprising:
computer usable code for determining whether a congesting vehicle in the subset is causing congestion in a route section neighboring the selected congested route section; and
computer usable code for skipping, responsive to the determining being affirmative, the route section neighboring the selected congested route section for the rerouting.

4. The computer usable program product of claims 1, wherein the populating comprises:
computer usable code for identifying, in the vacancy data structure, a second candidate route section neighboring the selected congested route section such that a direction of the second candidate route section relative to the selected congested route section corresponds to an orientation of the selected congested route section;
computer usable code for recording in the vacancy data structure a distance between the second candidate route section and the selected congested route section; and
computer usable code for recording in the vacancy data structure an available capacity of the second candidate route section.

5. The computer usable program product of claim 1, further comprising:
computer usable code for selecting the set of congesting vehicles from a set of vehicles positioned on the selected congested route section, wherein the set of congesting vehicles is a subset of the set of vehicles, and wherein the selecting employs a selection criterion.

6. The computer usable program product of claim 5, wherein the selection criterion for selecting the set of congesting vehicles causes that vehicle in the set of vehicles to be selected as a congesting vehicle whose route length is shorter than a route-length bound by a threshold value.

7. The computer usable program product of claim 1, further comprising:
computer usable code for identifying the set of congested route sections; and sorting the set of congested route sections.

8. The computer usable program product of claim 1, wherein the computer usable code is stored in a computer readable storage medium in a data processing system, and wherein the computer usable code is transferred over a network from a remote data processing system.

9. The computer usable program product of claim 1, wherein the computer usable code is stored in a computer readable storage medium in a server data processing system, and wherein the computer usable code is downloaded over a network to a remote data processing system for use in a computer readable storage medium associated with the remote data processing system.