MCC commissioned Roundabout Expert Michael Wallwork to prepare roundabout concept designs for California Ave at Hwy 1 in Moss Beach. The concept plans provide an idea as to approximate size and shape of possible roundabouts at this intersection. MCC provided these to the County for consideration as intersection improvements are contemplated.
The close proximity of the frontage road Carlos is the most difficult part of the design, although acute right turns and vehicle conflicts are probably no more restrictive or dangerous than existing conditions. Wienke Way, the fifth leg of the intersection, is accommodated by rerouting highway access slightly north. Vehicles entering the highway from Wienke would turn right only, and would go around the roundabout in order to head north on the highway.
Next step for California Ave intersection is a formal Intersection Control Evaluation (ICE) as required by Caltrans when intersection improvements are contemplated. The ICE for Cypress has already determined that “a multi-lane roundabout will better improve operations, increase safety, and be more contextually sound, as compared to a signal.” (evaluation - 10% design - Wallwork review) These two intersections must be considered together for a context-appropriate circulation plan for Moss Beach. Connect the Coastside draft plan indicates that Cypress and California are the only Midcoast highway intersections that have sufficient current and future side street traffic volume to warrant signalization or roundabout.