Modern Roundabouts
- a safer choice

  • 75% fewer injury collisions & 90% reduction in overall fatalities.  Highest crash rates of all Midcoast intersections are at traffic signals. 

  • Keep traffic moving through intersections.

  • Significantly less delay for peak-hour cross-street traffic. 

  • Increased intersection capacity due to lower speeds and resulting smaller gaps between vehicles. 

  • Fuel consumption/emissions reduced by less vehicle idling and not starting from a complete stop. 

  • Large trucks can make U-turns via the central truck apron. 

  • Traffic calming in village areas

  • Safe pedestrian crossings, one direction of traffic at a time, set back from entry points.

  • No blinking red signal malfunctions causing extensive backups. 

Roundabout Designs

Hwy 1 roundabout at Simpson Ln, Fort Bragg, was constructed as two-lane (aerials: 2011 & 2013) and later modified as single-lane (2018 aerial).

Examples of elliptical roundabouts designed by roundabout expert Michael Wallwork.


Hwy 1 Roundabouts for Moss Beach

The 2012 Hwy 1 Safety & Mobility Studies introduced the concept of roundabouts for improved traffic circulation in Moss Beach. A roundabout at each end of town would calm highway traffic without stopping it and favor right-turn side-street highway entry with convenient U-turns at each end of town.  

Whatever misgivings people may have had about unfamiliar roundabouts seemed to evaporate when two traffic signals were proposed for Moss Beach (at California and Cypress) in the 2016 draft Connect-the-Coastside recommended transportation improvements.  That year MCC asked Supervisor Horsley to support roundabouts instead of signals in the Midcoast. He agreed and has followed through.  

Cypress/Hwy 1

Intersection Control Evaluation by County traffic consultants DKS used traffic data gathered in June 2017, showing that existing conditions already meet the signal warrant at Cypress, without the Big Wave Project:

“As evidenced by current operating conditions, the two-way stop control at Cypress Avenue and Highway 1 is failing to meet demand and operate in a safe and efficient manner. A multi-lane roundabout will better improve operations, increase safety, and be more contextually sound, as compared to a signal. A single-lane roundabout is the safest alternative, but the limited capacity of the roundabout itself hampers operations along Highway 1 to an unreasonable extent. For these reasons, a multi- lane roundabout is the preferred alternative, followed by a single-lane roundabout and signalization. The “no-build” alternative, keeping the current two-way stop control, is the worst alternative now and in the future, in terms of both operations and safety.”

Cypress roundabout 10% design - MCC 3/28/18 review
12/26/18 Caltrans letter re funding for Cypress roundabout

California/Hwy 1

Traffic Impact Analysis for proposed Cypress Point affordable housing (Kittelson July 2018, Table ES 2) indicates peak-hour existing conditions at 2-way stop-controlled California Ave are Level of Service (LOS) F.  Roundabout or signalization would improve the peak hour LOS to A or B.
MCC provided concept designs for California Av roundabout by Michael Wallwork Nov 2018.