St. Louis County readies 'Operation Smart Street' to give emergency vehicles and transit signal priority

St. Louis County staff briefed the Peer Advisory Committee on Operation Smart Street, a program to add roadside units at traffic signals to enable emergency‑vehicle preemption and transit priority.

Glenn Henninger, division manager for Project Development, said the county has identified funding and is beginning design work for roughly half of the planned deployment. "The roadside unit can be used by emergency responders with the proper equipment in their vehicles to control traffic signals as they approach and make their crossing," Henninger said, adding that transit operators with compatible equipment can receive green‑time extensions to improve on‑time performance and reduce emissions.

Henninger said the system’s emergency function will allow preemption (changing signals to clear intersections), while transit vehicles could extend green time when close to a cycle. Staff expect the program to begin within the next year.

Why it matters: signal preemption can shorten emergency response times and transit priority can make bus service more reliable and reduce vehicle idling. County staff said equipment compatibility for emergency and transit vehicles will be a key implementation detail.

Next steps: advance design for planned corridors, coordinate with emergency services and transit agencies on equipment and protocols, and schedule deployments as funding and installation capacity allow.