Until someone can prove otherwise, looks like OKC can claim the distinction of having the state's first modern roundabout on a public street. Two in fact...one at 10th Street and Walker and the other just west at 10th Street and Shartel. Both replaced signalized intersections and were completed in 2008-ish.
Fast Facts
-Inscribed circle diameter = about 120'
-Walker R/A has about 1,200 vehicles per hour circulating flow in the PM peak hour (on 4/2/09)
-City-provided daily traffic is unreliable because of street closures and construction during counts, but indicates about 5,000 vehicles (which does seem low if the PM peak hour is any indication).
-Both have extensive streetscaping and landscaping (including pavers in the crosswalks...a point of contention in Tulsa right now..and at one spot they were failing Tulsa-style).
Commentary
Nearby business owners seemed supportive and enthusiastic about the track record so far. It was somewhat harrowing watching traffic move thru as some people aren't yet sure how to navigate. Entering vehicles should always yield to traffic on the left and not worry about traffic to the right. In light traffic, I noticed a good portion of motorists arriving simultaneous would treat it like an all-way stop...yielding based on "first-come, first-serve". I even saw several instances where the upstream driver, who always has right-of-way, would wave on the downstream driver...just like you would see at an all-way stop! This was much more frequent for the approaches that were in close proximity of each other....further support of maintaining as much seperation as possible between entry points.
On the flip side, some people were just downright rude! Either very unforgiving or too impatient with overly-cautious drivers. And some honked at upstream vehicles that were entering just as they were attempting to...even though upstream has right-of-way! Overall, I would assign a HHPH (horn-honks per hour) factor of 10 to this intersection. I've seen worse but that's an indication we've got a ways to go to enlighten the masses on how to drive these things. I think all new roundabouts should include a "BE NICE!" sign as part of the advanced warning assembly. Yes I know it's not in the MUTCD but neither are half the signs you see (or at least you should be seeing) at a typical roundabout.
Speaking of advanced warning signs, I also noticed that many of the two-lane approaches are merged into one lane upstream of the R/A without any such said signs. Poof....the lane just disappears. Doesn't seem to be a problem with the low speeds and volumes observed here...people seem to figure it out.
10th Street @ Walker R/A:
10th Street@ Shartel R/A:
32 seconds in the life of the Walker R/A:
Video of firetruck driving thru Walker R/A
(let's see you do THIS at a red light, Sparky!):
