Options narrow for El Camino, 92 interchange
Gladwyn D'Souza
As Caltrans looks to widen State Route 92 from Interstate 280 to Highway 101, it is also looking at ways to improve traffic conditions at the interchange that feeds the route at El Camino Real in San Mateo.
Caltrans has been studying how to widen State Route 92 since 2001 and has indicated the cloverleaf configurations at El Camino that feed the highway can lead to poor traffic conditions on the route, especially where it meets Highway 101.
Five options are being considered to improve the interchange, including converting the existing cloverleaf configuration to a “partial cloverleaf” configuration.
The option would require the elimination of two loop ramps and the construction of diagonal off-ramps, according to a staff report.
The city is currently in the process of developing a cooperative agreement with Caltrans that the City Council will vote on in February or March.
Cost for the work is expected to be up to $15 million and San Mateo is currently sitting on a $2.8 million grant from the federal government for the design and construction of the project. The city is also seeking about $5 million for the project from the Metropolitan Transportation Commission. The MTC initiated a study in 2010 to examine the conditions at the interchanges in conjunction with the City/County Association of Governments, San Mateo County Transportation Authority and the city of San Mateo.
The focused study also favored an option that calls for constructing partial cloverleafs at the interchange with the widening of State Route 92 by one lane in each direction. This option was first proposed more than 10 years ago.
The other three options include:
• Conversion of the northern half of the interchange to a diamond configuration. The two existing loop ramps would be eliminated. The existing westbound-to-northbound diagonal ramp would be widened. A left-turn lane would be added to northbound El Camino Real. The existing southbound-to-westbound diagonal ramp would be relocated to fit the new intersection which would be controlled by a traffic signal.
• Conversion of the northeast quadrant of the cloverleaf to a diamond configuration. The northbound-to-westbound loop would be eliminated, with a northbound left-turn lane on El Camino Real provided. The westbound-to-northbound ramp would be widened for additional lanes and signalized at El Camino.
• Conversion of the existing full cloverleaf configuration to a diamond configuration with modifications to the State Route 92/Delaware Street interchange. The westbound on-ramp from Delaware would be connected to the westbound off-ramp to El Camino Real. The off-ramp from eastbound State Route 92 to Delaware would be eliminated. Traffic wishing to reach Delaware Street would exit at El Camino Real, proceed through the intersection of the off-ramp and onto the eastbound on-ramp.
The City Council will hear an update on the project at a special study session, 5:45 p.m., tonight, conference room C, City Hall, 330 W. 20th Ave., San Mateo.