An Application of Client/Server Architecture in Interfacing Virtual Traffic Signal Controller with CORSIM

摘要

Traffic simulation, interfaced with traffic signal controller or traffic control algorithms, can be used to evaluate traffic operations and traffic control in a laboratory environment. This virtual environment can be integrated through client/server computing approaches. The CORSIM (CORridor SIMulation) is microscopic traffic simulation software developed by the Federal Highway Administration. It is distributed as a part of the Traffic Software Integrated System (TSIS). The TSIS suite is a collection of software tools used to support CORSIM. TSIS provides an Application Programming Interface (API) between an external application (e.g. a traffic control application) and CORSIM. This type of interface is known as a run time extension (RTE). To overcome the limitations of CORSIM RTE, a new type of CORSIM client/server API was proposed. The client API was defined and developed to interface CORSIM with a third-party virtual traffic controller server. The new client application needs few source code changes for different servers by different vendors. A railroad preemption case was designed to test the architecture and the client side software. Sample cases ran successfully in real time on a TCP/IP network with no program execution delays. This paper exemplifies how the client/server application can benefit highway railroad traffic signal preemption studies. The example cases show the dynamics of area traffic (including railroad traffic), traffic control devices and other factors have been systematically and realistically captured in evaluating railroad preemption design.