Sunnyvale traffic diversion

VTA and Sunnyvale staff collaborated on a presentation about the El Camino Real BRT Project for a joint study session of Sunnyvale’s City Council and Planning Commission last night.  The study session was well attended and we were impressed with the level of interest and volume of questions and comments that were received.  The study session served as a forum for council members, commissioners and members of the public to share their input on the project.  On May 22, the City Council will be asked to take an action on whether to recommend that VTA’s upcoming environmental studies feature a dedicated lane street configuration in Sunnyvale.

There was a lot of interest in the issue of traffic diversion and possibly also some misunderstanding about the effect that traffic diversion would have on other roads in Sunnyvale.  Some commenters appeared to be under the impression that the pie charts below represented increases in vehicle volumes on the respective roadways, rather than the destinations for the shares of diverted traffic from El Camino Real. We’d like to use this space to go over the traffic diversion projections and discuss what it means for Sunnyvale.

VTA’s recommendation for the corridor is to convert the travel lane closest to the median into a bus-only lane on both sides of El Camino Real.  That would leave two lanes for autos in each direction. VTA’s computer transportation model projects that the reduction of one-third of capacity on El Camino Real would cause about one-third of drivers who would use El Camino Real if there were no bus-only lanes to find other methods to reach their destination.  The model projects that some would convert to the new BRT service and those that opted to drive would take other routes.  So which routes would they take?

VTA undertook a screenline analysis for Sunnyvale by having the model project traffic volumes on alternate routes at the point where they cross Mathilda in the project and no project scenarios in 2015 and compared the differences.  The chart below shows the projected choices that diverted eastbound auto drivers (which amounts to 415 cars) on El Camino Real would take during the PM peak hour if two lanes on El Camino Real are converted to bus-only lanes.

110 of the 415 trips are projected to convert to the transit mode.  The rest of the trips are projected to disperse over nine different routes including US 101 and I-280.  The resulting increases in vehicle volumes on those routes are relatively small and mean that those routes will, for the most part, continue to operate at similar vehicle volumes with or without the project and below capacity.

	Peak Hour Eastbound Vehicle Volumes
Projected Choice	No Project Scenario	Project Scenario	% Change with BRT Project	% of Capacity Used in Project Scenario
Transit	-	110	-	-
US 101	5,945	6,039	+2%	79%
Remington	120	128	+7%	7%
Fremont	617	661	+7%	35%
Evelyn	206	264	+28%	15%
Washington	68	71	+3%	13%
California	450	452	+.4%	82%
Central Expressway	2,805	2,831	+1%	98%
I-280	7,069	7,092	+.3%	81%

 

The chart below shows the projected choices that diverted westbound auto drivers (which amounts to 149 cars) on El Camino Real would take during the PM peak hour if two lanes on El Camino Real are converted to bus-only lanes.

54 of the 149 trips are projected to convert to the transit mode.  The rest of the trips are projected to disperse over eight different routes with Central Expressway and Homestead making up the majority.  The resulting increases in westbound vehicle volumes on these routes are much smaller than the eastbound vehicle volumes and, as such, have a much smaller effect on auto traffic.

	Peak Hour Westbound Vehicle Volumes
Projected Choice	No Project Scenario	Project Scenario	% Change with BRT Project	% of Capacity Used in Project Scenario
Transit	-	54	-	-
Remington	152	155	+2%	8%
Evelyn	141	142	+1%	+.8%
Washington	154	155	+1%	28%
California	148	155	+4%	28%
Central Expressway	2,174	2,234	+3%	77%
Maude	296	300	+1%	16%
I-280	1,096	1,114	+2%	73%

This is just the beginning of VTA’s traffic analysis for Sunnyvale (and the entire six-city corridor). As the project moves into the environmental impact study in the coming months, detailed level of service analyses will be undertaken for 32 intersections in Sunnyvale (and many more intersections throughout the county) that could be affected by the project. Throughout that process, VTA will continue coordinating with each of the six cities to ensure that all city concerns are being studied and to identify mitigations for any traffic impacts that are identified by the study.