Walnut Creek Council authorizes city to join I‑680 ramp‑metering pilots to ease congestion

Walnut Creek’s City Council on June 16 authorized the city manager to execute a memorandum of understanding with the Contra Costa Transportation Authority and Caltrans to participate in two coordinated ramp‑metering pilot projects on Interstate 680.

Traffic Engineer Matt Redmond introduced the proposal, saying the MOU documents roles, expectations and policy governance for both agencies’ systems and emphasizes local‑agency considerations for adjacent arterial streets. “It’s not just a care about the freeway main line — we also care about local arterials,” he said, urging the MOU include local agency focus and operational coordination.

Stephanie Hu of CCTA described the two layered projects: Caltrans’ ARM (Adaptive Ramp Metering) and CCTA’s CALM (Coordinated Adaptive Ramp Metering). She said the deployments will add vehicle detection, CCTV and algorithms that adjust metering in real time to prevent mainline bottlenecks and discourage cut‑through traffic on city streets. Molly Mad, the Caltrans project manager for Contra Costa County, said ARM uses real‑time loop and detector data and that earlier deployments have produced notable mainline travel‑time reductions.

Scott Patera, a consultant for the CALM design, said CALM will add detection on ramps and coordinate metering rates across ramps so upstream ramps can react if a downstream queue grows. He described a three‑year demonstration focused initially on northbound I‑680 from Alcosta to Barnett and said construction is expected to finish in 2028 with full operations by early 2029.

Councilmembers pressed presenters on how the systems will avoid creating vehicle queues that spill back onto city streets. “Is there anything to monitor what’s going on in the streets?” asked Councilmember Vinny, who urged clarity about whether detection and monitoring extend beyond the ramps into adjacent arterials such as Olympic Boulevard and Buskirk Avenue. Staff and presenters said the pilot includes arterial travel‑time and delay metrics, third‑party probe data and CCTV; they also committed to installing additional ramp detection and selective arterial sensors at known pinch points.

Presenters described an initial calibration period during which algorithms will be tuned, quarterly technical coordination meetings and a public‑outreach program (video explainers and farmer’s‑market tabling). They cited prior demonstrations (I‑15 in Riverside and a Colorado pilot) where average ramp waits rose by approximately one to two minutes while mainline travel times improved.

After brief public comment and follow‑up questions about local impacts (including design changes at the Lawrence Way interchange to limit weaving and accommodate truck access to the city yard), the council voted unanimously to authorize the city manager to execute the MOU. The vote follows staff assurances that arterial impacts will be monitored and that the MOU and a forthcoming user manual will document operations, maintenance and performance measures.

Next steps: staff will finalize the MOU, continue technical coordination with CCTA and Caltrans, provide design visuals to city operations staff, and implement the planned baseline data collection before meters are activated so the city and partners can evaluate arterial impacts during the three‑year pilot.