Embedded system platform for safety-critical road traffic signal applications

Abstract

Road traffic signals are used to signal information to drivers (e.g., red signal to stop). A controller residing in a local cabinet is managing the traffic signal. Depending on the desired traffic situation, the corresponding traffic signal is switched on or off via the power line. For the time being, there is no programmable logic included in each traffic signal. As a result, there is a single type for each application available e.g., due to different power supply levels or light output. In addition, functionality of traffic signals is limited so that its status information cannot be retrieved. This paper presents an approach to traffic signals for safety-critical applications based on an embedded system. It includes a presentation of safetyrelated hardware and a microcontroller with embedded safety-related firmware. The result is a platform to be used in various applications and meeting safety and performance requirements according to standard EN 50556 and VDE 0832. © 2013 Springer-Verlag.