The Johannesburg Roads Agency implemented an ITS system which managed all the intersections in the city and a Bus Rapid Transit system. Part of this project was to develop a Traffic Signal Adaptor (TSA) which was used as a communication interface between the Advanced Traffic Management System and the various proprietary traffic signal controllers. The TSA adaptor converted the proprietary protocol to NTCIP protocol. This provided a standards based interface to all the intersections in Johannesburg. This project standardized the interface the Traffic Controllers and also provided an interface for the Bus Rapid Transit system to connect to the traffic controllers.
Scope of Services:
Intelligent Devices developed a Traffic Signal Adaptor that could communicate with multiple traffic intersections with a standard NTCIP interface. This project utilized the IDI 1321 embedded micro-controller to communicate to all the intersections. These TSA devices communicated to central system using either Wi-Fi or cellular technologies.
The scope of work included:
- Developing a Standard NTCIP/SNMP Management Information Base (MIB) to support the Siemens ST800 traffic controllers and PLC traffic intersections.
- Design of the Traffic Signal Adaptors.
- Developed two custom drivers to communicate to the Traffic intersections.
- The TSA supported communications to PLC “Dumb” traffic intersections controllers that monitored status and health by monitoring the input power, the 220V power to the traffic signal heads and loop detectors through a custom designed I/O card.
- The TSA supported a more sophisticated interface to the Siemens ST800 Controller utilizing the Siemens Handset Protocol. This allowed for monitoring of phase status, system health, and the upload and download of traffic plans.
- The project first installed 200 TSA adaptors and plans to install a further 1600 TSA adaptors.