The TSIS/CORSIM traffic simulation model provides a detailed microscopic simulation of complex traffic operations. The simulation is based on traffic demands, street geometries, and a traffic control plan. The control plan includes both fixed time and actuated traffic signal controller logic. However, CORSIM’s actuated controller logic is generic and lacks many of the standard features available on today’s traffic controllers, particularly those that are specific to each manufacturer’s controller. In addition, CORSIM cannot adequately simulate many of the latest advanced real-time control systems and their logic. Finally, it is nearly impossible to test an actuated control signal-timing plan fully before it is implemented in the field.
NIATT’s Controller Interface Device (CID) gives the traffic engineer the opportunity to test any signal-timing plan that can be operated with either a NEMA or 170 traffic controller, using the traffic simulation logic built into CORSIM. The concept, known as hardware-in-the-loop simulation, is simple. CORSIM simulates traffic flow based on the traffic demand, street geometry, and control plans for a given scenario. When vehicles arrive at an actuated signalized intersection, CORSIM sends a simulated detector call, not to its own internal signal controller logic, but to a real traffic controller. Based on these detector calls, the traffic controller sends back signal phase indications to CORSIM. The CID makes this real-time data exchange of detector calls and phase indications possible.
The CID is one of several key elements of FHWA’s long-term Intelligent Transportation Systems research and development agenda for its Turner-Fairbank Advanced Traffic Engineering Laboratory. The CID provides a means to test advanced traffic control logic and is a tool need by traffic engineers to test signal timing plans before they are installed in the field. FHWA has asked NIATT to design a version of the CID that builds on the pioneering work of Darcy Bullock of Purdue University.
This new version would:
- Use faster communication links
- Handle up to 20 individual intersections
- Be easily manufactured
- Be much smaller and more portable than the current version
- Be more easily configured
During the first phases of this project, the UI project team developed several prototype versions of the CID and two software applications. The team will complete eight pre-production prototypes and sixteen production prototypes by August 2000. These prototypes will be tested by the UI team and by external reviewers. External reviewers will also test the software applications. The UI team hopes to complete a license agreement with a traffic signal manufacturer by late 2000.