Wednesday: Atherton council considers study of Alameda roundabout

The town of Truckee has been an early adopter and proponent of roundabouts. Having a 2nd home there for 20+ years, I can attest to the dramatic improvement roundabouts have brought to many troubled intersections where they have been implemented. They just work. Congestion on all feeders is down, traffic flow is improved, accidents are way down, etc, and they are better/safer for bicyclists as well. I really don't know why we don't have more of them here. I encourage the Atherton City Council to contact the appropriate city officials in Truckee to learn from their success.

This intersection is a nightmare during the morning and afternoon commute. It is long overdue for a change. But, is a round-a-bout the optimal solution?

A virtue of a traffic signal would be the packetizing of groups of cars on Alameda de las Pulgas. This grouping would make it easier to enter that thoroughfare from Walsh Road and other cross streets both north and south. A round-a-about promises a constant stream of cars.

I'm not sure if a roundabout or traffic light is the right solution. There are some roundabout's that have been built into Campus Drive at Stanford, and they work well, but at pretty low traffic volumes compared to the Alameda at rush hour. I'm inclined to believe that a regular old stoplight with pressure sensors would be a huge improvement. While they're at it they should fix the botched pavement repair job from several years ago -- it was bumpy from day 1 and has only gotten worse with time.

Why not put up a standard red stop light? Is Atherton opposed to stop lights on aesthetic grounds or something?

I agree that too many cars are running the current stop signs and something must be done.

Roundabouts are better than stop signs and stoplights from an environmental perspective because they reduce emissions from idling vehicles.

Grew up in Massachusetts. We call 'em Rotaries. Terrible solution, causes lots of confusion esp. when drivers aren't used to them. Stop light better.

Roundabouts are safer, support higher traffic capacity, cheaper to maintain, more environmentally friendly, and more aesthetically pleasing than signlaized intersections
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Re traffic on The Alameda: in addition to the horrendous backups at Atherton Avenue, the traffic light one block from Woodside Road on The Alameda often turns red to the major traffic on The Alameda to let one or two cars enter from the side street. The result is long backups of cars awaiting to turn from Woodside Road on to the Alameda. Why is this traffic light so sensitive?

Roundabouts work and are a brilliant solution for those who know how to navigate them (merely requires basic driving skills and an understanding of taking turns). By far, the best solution to long stop sign waits during times of heavy traffic flows in that intersection. Bravo, bring on the study!

Modern roundabouts are the safest form of intersection in the world (much more so than comparable signals). Visit Web Link for modern roundabout FAQs and safety facts. Modern roundabouts, and the pedestrian refuge islands approaching them, are two of nine proven safety measures identified by the FHWA, Web Link
The FHWA has a video about modern roundabouts on Youtube, or check out the IIHS video (iihs dot org).

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Modern, slow and go, roundabout intersections have less delay than a stop light or stop sign, especially the other 20 hours a day people aren’t driving to or from work (it’s the #2 reason). Average daily delay at a signal is around 12 seconds per car. At a modern roundabout average delay is less than five seconds. Signals take an hour of demand and restrict it to a half hour, at best only half the traffic gets to go at any one time. At a modern roundabout four drivers entering from four directions can all enter at the same time. Don’t try that with a signalized intersection.

Many people confuse other and older styles of circular intersections with modern roundabouts. East coast rotaries, large multi-lane traffic circles (Arc D’Triomphe, Dupont Circle), and small neighborhood traffic circles are not modern roundabouts. If you want to see the difference between a traffic circle, a rotary (UK roundabout) and a modern roundabout (UK continental roundabout), go to Web Link to see pictures. And here’s another site that shows the difference between an older rotary and a modern roundabout: Web Link

Roundabouts are what urban designers reach for when a real solution is not available. In practice, they simply turn into high speed obstacles for impatient drivers. Few if any drivers yield properly because few know the rules. I predict a new accident hot spot.

Palo Alto has built fake traffic circles in a few locations. There is a circle in the middle of the intersection, but also stop signs, which defeats the purpose of the circle. Did they do this because drivers were too confused by roundabout right-of-way rules? Or were drivers just going too fast for the width of the circle?

@resident

Those Palo Alto traffic islands were designed to impede traffic. That's why they have stop signs as well.

With Palo Alto's main streets heavily congested at rush hour, commuters use nearby residential streets as shortcuts. Those Palo Alto traffic islands discourage short cutting (to limited effect), but also get commuters to slow down.

OTOH, the Atherton roundabout is designed to improve traffic flow, as well as provide other benefits earlier commenters have noted.