Transportation Application Modules

There is a new master, multimodal equilibrium traffic assignment procedure that simultaneously assigns cars, trucks, and buses to the road network. There can be multiple user classes for cars (e.g. HOV users) as well as different classes (e.g. sizes) of trucks. This procedure includes the option of using exact entrance to exit tolls by vehicle class and differential values of time to be used in calculating generalized cost. Network exclusions keep each class of traffic restricted to the links that it is permitted to use. Some vehicles, such as fixed-route buses, can be pre-loaded on the multimodal network. Among the reporting options is a breakdown of link traffic by vehicle class and type.

Vehicle Routing and Logistics
TransCAD includes a comprehensive library of logistics procedures that apply to all modes of transportation and can be used to solve a variety of logistics problems.

Vehicle Routing/Dispatching
TransCAD provides a rich set of tools that solve various types of pickup and delivery routing problems. These tools are used to prepare input data, solve the routing problem, and provide tabular and graphical output of the resulting routes and vehicle schedules. The TransCAD procedures can solve many variations on the classic vehicle routing problem, including restrictions on the time when stops can be made, the dispatching of vehicles from multiple depots, and the use of non-homogeneous vehicle fleets. The vehicle routing procedure in TransCAD is also capable of solving problems involving mixed pickup and delivery. Once a solution is found and the results displayed graphically, users can edit the routes interactively by adding or removing stops. Once stops have been added or removed, users can perform a re-optimization of the route so as to minimize time window violations.

Arc Routing
Arc routing problems are a class of problems that involve finding efficient ways to travel over a set of links in a transportation network. Arc routing has a large number of public and private sector applications, including street sweeping, solid waste collection, snow plowing, mail delivery, and other door-to-door operations. In a typical arc routing problem, people or vehicles are dispatched from one or more depots to traverse a set of service links. The result of an arc routing problem is a set of one or more routes that cover all the service links with the minimal amount of deadheading.

Network Flow and Distribution Analysis
TransCAD includes a set of procedures for solving network flow problems. These problems involve efficient delivery of goods or services, and arise in transportation and many other contexts.

• The transportation problem involves identifying the most efficient way to service a set of destinations from a set of origins. For example, a company may be interested in finding the least-cost solution for shipping commodities from its warehouses to its vendor locations.
• The minimum cost flow problem is a more general version of the transportation problem that takes link capacities into account. For example, the procedure can be used to find multiple paths when capacity constraints make it impossible to utilize the shortest path for an entire shipment.
• Matching problems try to find the best one-to-one matching between two groups of objects where there is some quantitative measure to be minimized or maximized. For example, you can efficiently assign work to service centers.

Territory Management and Site Location Modeling
TransCAD procedures for regional partitioning, clustering, and facility location have broad applications in transportation and marketing. Clustering routines assemble customers, facilities, or areas into groups that are compact and can be serviced efficiently. Districting models group Census tracts, ZIP Codes, counties, or other regions into territories that are compact and balanced. Location models evaluate the costs and benefits of any number of proposed facility locations.

Territory Definition
TransCAD provides powerful automated procedures for defining territories:

• Partitioning involves creating groups of features in a layer based on proximity or measures of similarity. The partitioning procedures in TransCAD support applications in service territory alignment, sales and marketing, political redistricting, and many other disciplines. The partitioning model attempts to produce districts that are contiguous, compact, and balanced.
• Clustering is the grouping of features into compact clusters where there may also be limits on the size of each cluster. You can specify a maximum cluster size or capacity, which limits the number of features assigned to each cluster. The clustering procedure in TransCAD is very flexible and can be used to solve problems in many disciplines such as sales force deployment and vehicle fleet management.

Site Location Analysis
Site location problems involve choosing the best location for one or more facilities from a set of possible locations. TransCAD can address virtually all types of location problems. For example:

• You want to determine the number of facilities that are required to guarantee a prescribed level of service. You may also need to account for financial or operational constraints, such as an upper limit on the number of facilities you are able to add, or a fixed budget for adding facilities.
• Revenues and profits depend on the choice of facility locations. In these cases, you need to trade off the cost of adding a facility with the potential revenue benefit.
• You want to maximize the distance between facilities and the population they serve. Landfills and power plants, for example, are often located relatively far from major population centers.
• You want to consider the presence of existing facilities. The locations of these facilities obviously affect the choice of locations for new facilities. In addition, you may want to consider both adding new facilities and closing one or more existing facilities.