Pleasant Hill Road & Reliez Valley Road Traffic Issues

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In October 2015, recognizing increasing public concern regarding traffic congestion along Pleasant Hill Road (“PHR”), especially during the morning peak commute hours, the Lafayette City Council authorized a study of signal timing operations along the corridor. The study proceeded to evaluate potential strategies to improve traffic progression along Pleasant Hill Road within City limits, north of State Route 24. After developing and synthesizing traffic models and conducting numerous field tests, consulting engineers for the study recommended modifications in signal timing at certain corridor intersections, including redistribution of where traffic delays occur without increasing overall delay through the corridor. While this would likely increase delay to southbound travelers north of Lafayette, it would also aim to reduce wait times at locations closer to SR 24 and on side streets that intersect PHR.   The changes were shown to modestly improve overall corridor throughput.

In March 2017, the City Council accepted the findings and recommendations from this study. At the same time, the Council recognized that modifying PHR corridor signal timing plans could have secondary impacts, such as trip diversion to proximate north-south routes like Reliez Valley Road (“RVR”). To address this issue, the Council directed City staff to monitor traffic conditions along this parallel route.

As part of this directed RVR traffic monitoring effort, staffs have collected additional data and have also invited and received data from area residents. The data variety includes additional turn movement counts at the intersection of RVR/Withers Avenue, routing directions by Google Maps and Waze traffic navigation mobile applications, corridor travel times, and driver speed data. Results to date indicate occasional spikes in critical turn movement volumes at RVR/Withers and RVR travel times. While there is evidence that Google Maps and Waze regularly prioritize RVR as the fastest available north-south morning commute route, data from the limited sample size generally remains inconclusive as to whether this factor is directly causal to the travel time on RVR.

Because of the interjurisdictional nature of traffic issues along both PHR and RVR corridors, more recently the Lafayette City Manager also directed Engineering staff to engage Contra Costa County and City of Pleasant Hill colleagues to discuss potential solutions to PHR and RVR traffic congestion issues. While informative to date, it remains that Lafayette cannot legally impose unilateral regulations, by signage or otherwise, on roadways with shared jurisdiction or outside its boundaries.

The above process and associated data and analyses generated to date are documented in numerous 2017 staff reports to both the City Council (July 10; October 23; November 13; November 27) and the Circulation Commission December 4). On-going dialogue amongst various participating stakeholders has also generated a menu of congestion solution ideas, which is compiled for reference under “Information Resources” below.

Separate but related, the City Council has authorized a 90-day trial to test traffic safety measures on RVR, as recommended by the Lafayette Police and Public Safety Subcommittee. These measures include two additional stop signs, speed limit pavement markings, new turn regulation signage at the PHR/RVR intersection, and a crosswalk at RVR/Green Valley Drive. More information on this trial can be found in the November 13 and 27 reports to Council. This trial commenced mid-November and police staff will present a performance assessment to Council in February 2018.

What’s Next?

Lafayette staffs are continuing our engagement with Contra Costa County colleagues in the hope that at least a trial of some congestion countermeasures could be pursued.  Area residents within Contra Costa County’s sphere of influence are advised to contact their political representative on the Board of Supervisor.

In early 2018, the Circulation Commission will also conduct outreach with area residents and local school administrators to gauge preferences on solution ideas deemed legally feasible and aimed at reducing the “attractiveness” of RVR as a regional shortcut.  The Commission will also determine whether there is community support to form a Neighborhood Action Team (NAT), as described in the Lafayette Traffic Calming Guidebook.  

Informational Resources

The following web-based resources are provided as supplemental information on this topic: