The Evil Eyebrow

This Week in Traffic: 21 March 2007

Written by

Bill Ruhsam

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Elderly Fail to Yield

According to this news report, the U.S. Insurance Institute for Highway Safety published a study that says older drivers tend to have collisions due to failures to yield at intersections. They pull out at inappropriate times and are struck by oncoming vehicles.
Other age groups are prey to different types of collisions. 35-54 year olds tend to rear end people
An interesting quote, which I need to go to the IIHS report to find, is:

To prevent such accidents, the Institute is recommending more left turn lanes and arrows at intersections and roundabouts.

More misinformation about roundabouts! There shouldn’t be any need for (pavement) arrows at a well designed roundabout. Don’t get me started.

I read the IIHS report, and it refers to roundabouts and fewer permissive (allowable on a green ball signal) left turns, but no arrows at roundabouts. Perhaps that was a grammar parsing error. “Signal arrows at Intersections, and more roundabouts” might be better.

North Carolina Traffic Web Cams

My friends in the Raleigh, NC area may be interested in this download. Let me know if it’s any good.

Ad Censorship on Public Transit

Kezins had this to say about the Denver Regional Transportation District proposal to ban violent video game advertisements on its vehicles.

Blog Firestorm on Hampshire Congestion

Apparently a road agency in Southampton installed some traffic signals and lit off furious public responses. Check out the comments.

What freaks me out is this quote:

Agency route manager Guy Berresford said: “The new traffic lights on the roundabout will ease congestion at this location…

The British invented the modern roundabout, so why are they installing signals on something that is specifically designed to do away with them. I hope the writer is using the term “roundabout” in this case as a cover all for “round intersection.” Traffic Circle and/or Rotary does not equal Roundabout.

Transportation Madness!

York County, Pennsylvania is using an interesting tool to educate their public stakeholders as to the tradeoffs involved in transportation planning. To that end, they’ve developed the Transportation Madness bracket. Check it out.

Comments

3 responses to “This Week in Traffic: 21 March 2007”

  1. Ken Avatar
    Ken

    “There shouldn’t be any need for (pavement) arrows at a well designed roundabout. Don’t get me started.”

    Not being a traffic engineer, I’m not certain what a “well-designed roundabout” would look like. Logically, I think it would be a roundabout that has cars enter at an angle (to merge with the circle) rather than perpendicular (confusing American drivers, giving them the opportunity to turn left rather than right).

    I haven’t seen roundabouts used in high traffic areas of northern Virginia, but I have seen them on secondary roads servicing shopping areas. At once local roundabout, I’ve seen cars drive the opposite direction (towards oncoming traffic) on the roundabout. I blame the perpendicular entrances and lack of markings (“One Way”, “Right Only” should be posted).

    What’s a well-designed roundabout?

  2. Bill Avatar
    Bill

    Kittleson has a website talking about modern roundabouts. This is the intersection that is being discussed when you hear anyone in the transportation field say “roundabout” nowadays.

    To sum up, modern roundabouts have the features you described, with obvious direction for incoming traffic to go, no easy way to turn the incorrect direction, yield-to-traffic-in-roundabout priorities, and other design features that are a bit esoteric to get in to.

    To sum up: Modern roundabouts are excellent alternatives to signals or all-way stops. They do have thresholds of usefulness and some give/take vs. the other intersection types, but they are very good at reducing the severity of collisions and the amount of delay experienced by drivers.

    NY State has made the Roundabout the preferred alternative, unless it can be demostrated that it is less suitable than an all-way stop or signal.

  3. Bill Avatar
    Bill

    An addendum to that last comment: Roundabouts are not friendly to pedestrians. They do not provide a stopped traffic flow for pedestrians to cross the roadway. “This is a problem, and we are working on it.” There are a lot of proposed solutions to this, but nothing has risen to the top yet.

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