J2945/11 Recommended Practices for Signal Preemption Message Development
This effort will be a recommend best practices document outlining how to use the J2735 Signal Request and Signal Status messages in the standard relating to signalized systems status. It primary content will deal with explaining and demonstrating by small working examples how these messages are constructed and used to meet operational needs of user. Particular attention will be paid to the interaction between the SAE work and the relevant NTCIP standards used in the signal control system. [The SAE J2735 document, being a data dictionary and not a guide, allowed only a brief summary of this sort of material.] The intended audience for this effort are those developing new deployment using these messages in connection with intersection safety applications. This will be a recommend practice, not a standard.
Rationale: Multiple deployments, committee members, and new users are requesting additional information regarding how to map various existing and emerging control strategies to the relevant DSRC messages. The focus on this document will be on preemption and priority methodologies and how they are best implemented using the current message set. This work is also related to the way the geometrical description the signalized intersection is constructed and to the messages send the signal phase and timing information, which is handled in another track. As part of the examples to be developed, preemption in a common 4-phase controller will be developed as a working test case on an intersection. This will largely be based on prior pilot projects. Existing practices, at times thought to be best practices, will be laid out as guidance. Emerging control strategies which DSRC enables are less understood by the community of signal control practitioners, so the work will also entail some educational materials in this regard.