[BikeLongmont] Re: Traffic Circles Update

[Richard Masoner]

Victor Morin <victormorin at comcast.net> wrote:

> An update on the Mountain View traffic circles as of 02/21/2005 12:00.

We must have just missed each other! I rode down Mountain View to the
traffic circles shortly after noon. A photo of one of the temporary
traffic circles is now on my traffic circle page. You can also get
directly to the photos here:

 http://www.masoner.net/photos/bike/circles/

> I asked if the current configuration (especially the
> white barriers just before the traffic circle that cause the bikers to merge
> into the auto traffic) was temporary 

My very first thought when I approached those circles is that the
neck-ins aren't nearly large enough.

Circles with large flare-outs at the circle entrance are demonstrably
much more dangerous to bicyclists. You *want* the neck-in, and you
*want* to merge into the traffic to stay safe. 48% of roundabout
bicycle-car collisions are motorists running into bicyclists who stay
to the edge of the lane. Flare-outs increase the odds of fatality and
serious injury for bicyclists; neck-ins decrease the odds of fatality
and serious injury.

Other observations:

* Because the neck-ins aren't big enough, there's very little
horizontal deflection of traffic. The motorists I observed slowed down
very little at the circles. I think this guy slowed down almost to the
speed limit:

  http://www.masoner.net/photos/bike/circles/circleMtnView2.jpg

* Traffic circle guides recommend placing crosswalks at least a
car-length ahead of circle entry/exit so that pedestrians are more
visible to motorists. It appears Longmont actually moved the crosswalk
further into the circle.

* The bike lane stripes need to be removed about 50 feet from the
circle entrance, according to the FHA "Informational Guide."

RFM