As part of an investigation of improved traffic controllers, for possible intelligent vehicle highway system (IVHS) application, the paper introduces a computable language called TCBLKS (Traffic Control Blocks) that could provide the foundation for constructing real-time traffic engineering software. This computable language is designed to be configured by a graphical user interface that does not require extensive software engineering training to use yet provides more flexibility and capability than is possible by simply changing program parameters. The model is based on the function block metaphor commonly used for constructing robust and efficient real-time industrial control systems. Adapting this model to the transportation sector permits traffic control applications to be programmed by: (a) selecting preprogrammed function blocks from a standard library, (b) configuring block parameters, and (c) connecting blocks to other blocks in the strategy. The software model was implemented in C on an advanced traffic controller platform and demonstrated in real time for applications such as signalized intersection control and ramp metering. In addition, this same software model was used to control the rampmeters along a segment of westbound Highway 50 during a demonstration in Sacramento, California, in November 1992. (A)
Abstract