Category Archives: roundabouts


Students Learn About Roundabouts

by James Sievert, Safe Routes Insructor

Can you name all the roundabouts in Marin? Do you know where the newest one is being built?

It might be surprising to many people that our curriculum includes instruction and practice with roundabouts as the underestimated circular intersection is rarely seen in this neck of the woods. Advocates for safer streets have long touted their benefits and we hope our kids will soon be navigating more circles with triangular signs instead of squares with octagon signage.

Roundabouts are also being used to help cyclists navigate intersections on bike paths. The bike path in Mill Valley near the middle school has a new multi-use path roundabout.  There is also new  roundabout for cyclists at the base of the new bridge/pathway near the Larkspur Landing ferry building.  These roundabout encorage cyclists to slow down at intersections and provide direction for cyclists to merge safely and efficiently.


Mill Valley Bike Path Roundabout

Fact or Fiction?

Sure, drivers unfamiliar with roundabouts are occasionally confused and (despite clear signage) occasionally turn the wrong way when entering. Thankfully roundabouts reduce the speed of cars such that any potential collision is likely non-lethal. In fact, roundabouts reduce fatal injuries by over 90% and serious injury by 75% compared to stop and signalized intersections.   In addition to increased safety, the roundabout has been shown to help people get to destinations more efficiently and therefore, faster.


Travel Time vs. Car Speed

Counter-intuitively, travel time and car speed are not always related. Perhaps we remember the story of the tortoise and the hare? Going really fast and then slamming on brakes is not a better system than going slow and steady. The roundabout embodies this sentiment with a form that reduces car speed (increasing safety) and function that creates faster travel time. Search for “Mythbusters” and “Roundabout” and you can see why these traffic circles flow 20% better!

We’re proud to instruct Marin’s students on how and why roundabouts work. They certainly outperform the stop signs at our school courses and unlike stops can be ridden with little supervision.