Everything You Ever Wanted to Know About Roundabouts


Oregon Transportation Research and Education Consortium (OTREC) Professional Development Course *Roundabout Analysis and Design*, May 7-8, 2008 at Portland State University

Course description: http://otrec.us/content/otrec_roundabout_08.pdf
Registration form: http://otrec.us/content/otrec_roundabout_08_reg.pdf

The roundabout has emerged as one of the safest and most efficient methods of managing the transportation system, with increasing use`in the Pacific Northwest and around the United States. While roundabouts can often function well under a variety of conditions and design constraints, their design requires careful attention to design details to maximize safety and operational performance.`The instructor experts for this course will present the latest findings and guidelines relative to the development and design of the modern roundabout. In this course, you will review the interrelationships between design, safety, and operational performance as they apply to roundabouts. You will also review the techniques used to successfully accommodate all modes of transportation, including pedestrians and bicycles. You will apply these techniques through a variety of case studies and hands-on exercises covering single-lane roundabouts, multilane roundabouts, and peer reviews of other designs.
The basis for the course is the FHWA document entitled, Roundabouts: An Informational Guide, various State supplements, recent national research and committee activity, and the practical experience of the instructors.

Format: This 2- day course will include classroom instruction and discussion, application of course content through problem-solving and case studies. The course will start at 8:00AM both days. Light refreshments, lunches and course materials are included.

**Who Should Attend: This course is appropriate for transportation planners and traffic engineers responsible for planning, implementation and evaluation of traffic control devices; public officials charged with the evaluation of traffic control alternatives; and planners and urban

Instructors: Brian Ray and Wade Scarborough, Kittelson & Associates, Inc

For More Information: contact Robert Bertini at OTREC at 503-725-4249 or bertini@pdx.edu. Fax to 503-725-5950.

Registration: Early registration is $295 before April 15, 2008. Please register by April 15!


0 responses to “Everything You Ever Wanted to Know About Roundabouts”

  1. I personally am impressed by the bus drivers that handle the circles/roundabouts/obstacles on NW 25. It’s quite impressive to ride with, though a little nerve wracking.

    They all do it well, very impressively.

  2. The roundabout at 39th and Glisan is a total failure.

    FYI, that wasn’t from me.

    Personally, I find the 39th/Glisan circle moves traffic quite effectively. I never have to wait more than a few seconds at off-peak times, and never more than 30 seconds at peak times.

    The only real problem at 39th is that cars exiting the roundabout rarely stop for pedestrians.

  3. It would be interesting to see how 39th & Glisan operated with no signs other than “Yield.” It is over-regulated IMO, which decreases its thru put.
    Otherwise, Portland’s little traffic circles, speed bumps, curb extensions have no effect at all on motor vehicle traffic…IF you are driving the posted speed. I guess that is the point; some of us have trouble reading numbers and behave accordingly.

  4. As someone who uses the Joan of Arc roundabout on a daily basis (often more) I have to strongly disagree with Bob R. and, I guess, Lenny. It is essentially a four-way stop but drivers regularly behave as they never would at a standard four-way. I’ve nearly been creamed a number of times because one or two cars will pull out immediately behind another car, without any consideration at all for the car that is waiting at the stop to the right.

    It is hardly “over-regulated”.

    Driving last year for two weeks in the UK, I experienced a huge number of roundabouts, big and small. Once I began to understand the basic concept and the etiquette, the simplicity and value of the design made a lot more sense to me. Part of what makes them work is the wayfinding signage. Approaching the roundabout, one sees a clear map of the routes, each well-marked and visually defined as to their hierarchy — and these are intersections rarely limited to a simple right-angle crossing.

    39th & Glisan has nothing equivalent, and it’s often obvious that drivers have inadvertently but understandably stuck themselves in the wrong lane. The inclusion of the bus lanes moving in contradiction to everyone else, simply increases the confusion (and a bus at one of their stops makes it impossible to see anything until they’ve moved out of the intersection entirely).

    And, as someone who has danced through the crosswalks there repeatedly, I would say that drivers are generally *more* respectful there than anywhere else in town, possibly because they’re already having to stop prior to the crosswalk.

  5. The Joan d’Arc circle is unique, so we don’t know what to do with it, stop signs not withstanding. Some years ago it was less regulated; maybe there were some accidents, etc. New unregulated intersections in The Netherlands and elsewhere have proven to be safer for all users as well as more efficient…more thru put for motor vehicles…than ones with lots of sign, paint, arrows and what not…distractions really, when one should be watching out for the other driver.

  6. I would say that drivers are generally *more* respectful there than anywhere else in town, possibly because they’re already having to stop prior to the crosswalk.

    I agree that they tend to be respectful of pedestrians when stopped — the problem for me is those cars exiting the circle — they don’t have stop signs.

    I use the circle several times a week — I guess my experiences driving through there have been luckier yours.

    I don’t think that the bus stops are moving in contradiction to everyone else — but it is a visibility issue as you mention.

    For those who aren’t familiar with the intersection, here’s a link to a photo of the 39th/Glisan traffic circle:
    Google Maps Aerial View

    The bus stops are marked by Google — each of the 4 directions has it’s own bus stop/island with shelter.

  7. I don’t think that the bus stops are moving in contradiction to everyone else — but it is a visibility issue as you mention.

    I probably could have phrased it differently, but what I meant was that the right-hand lane forces cars to turn right but not buses. For the unfamiliar, this makes the intersection just that much weirder when the oncoming bus doesn’t need to make a stop.

    As to my experience, I’d add that the largest number of problems have occurred during the morning rush hour. Maybe people are just more impatient then.

  8. The roundabout at 39th and Glisan is a total failure.

    Failure is a very nice way to put it. Complete waste of space, money, and effort. They might as well just close the circle and put four, four-way stops. It probably would be safer for those pedestrians and it wouldn’t decrease traffic much worse than it already does.

    The fact of the matter is that the stupid thing is NOT setup as a true to case well built/designed round about. It’s completely retarded.

    Not that I drive much, I think I’ve driven through this area about 3 times in the last 3 years of living in Portland. I’ve however been through there on the bus a number of times, and even then, it is obvious that the circle has “fail” all over it. Even conversations would spring up on the bus on a regular basis about how “retarded” this round about is.

    …maybe…

    …one day someone can fix it and toss yields back up instead of stop signs. Better yet make the circular inner roadway operate appropriately too.

  9. Complete waste of space, money, and effort.

    The roundabout (named “Coe Circle” as it turns out) was built by private developers as part of the platting of the original Laurelhurst neighborhood.

    See this historic map of Laurelhurst.

    A streetcar ran along Glisan from the 1891 and was extended all the way out to 91st around 1911, replaced by gas bus in 1948. The streetcar tracks ran right through the center of the circle!

    Here’s a neighborhood wiki article on the history of Coe Circle.

    From the article, here is an amusing history blurb about what might be characterized as the neighborhood’s early opposition to Transit-Oriented Development… :-)

    In late 1921, the Company sold the property to the McFadden Building Co. who announced they would build a residence-type building to house a streetcar waiting room, drug store, grocery store, and market. Neighborhood residents obtained a court order stopping construction because the Laurelhurst Co. had agreed to exclude businesses from Laurelhurst.

  10. 39th & Glisan IS NOT A ROUNDABOUT.

    Sorry to shout, but drawing conclusions about how a roundabout operates from the traffic circle at 39th & Glisan is like deciding you don’t like donuts because your bagel was too chewy.

    Roundabouts have full yield control, shallow approach and departure angles to moderate speeds, and comparatively high capacities. 39th & Glisan is an obsolete traffic circle design that operates poorly. Simple geometric conversion to a roundabout would probably solve all of its problems.

    I won’t cite any local examples, since there are few high-profile roundabouts in the Portland metro area. Astoria has a good one, and Bend is full of them.

    Two good websites for learning:
    http://www.roundaboutsusa.com/
    http://roundabout.kittelson.com/
    Or – better yet – sign up for the class and you might actually learn something.

  11. To convert 39th & Glisan to a typical 2-lane roundabout:
    1. Replace stops with yields
    2. Tighten up approaches and departures to moderate speeds and make crosswalks safer
    3. Convert right-turn lanes to general purpose lanes
    4. Move bus stops to departure legs, add pullouts
    5. Add wayfinding
    The circle could even be shrunk quite a bit for speed control, although the neighborhood might prefer it stay the size it is.

  12. Unit –

    With respect to terminology, do you mean with respect to modern standards? Would this not have been considered a roundabout 50 years ago?

    The 2nd web site you mention lists the Glisan/39th intersection in its database of “roundabouts”, but with a type of “other” and in the notes it says “Historical rotary with stop control.”

  13. Traffic circles are used in Europe because they have a higher throughput than traffic signals. And are safer, because they prevent head-on collisions. However, they do require people to wise up and get off their cellphone, otherwise they will hit someone.

    The 39th and Glisan roundabout shouldn’t have stop signs. Also, putting bus stops inside the roundabout… not to mention people’s driveways… is also a bit nutty. What is PDOT thinking???

    Next they’ll have personal driveways off I-5?

  14. What is PDOT thinking???

    Well, PDOT didn’t design this intersection … as mentioned earlier the private developers of the neighborhood built it that way (except for the stop signs?), driveways and all. However the bus stops didn’t exist like that until the late 40’s (a streetcar ran through the middle of the circle).

    Maybe removing the stops and introducing yields and better signage will improve things, but don’t blame PDOT if you don’t like the circle.

  15. I think this is better described as a historic rotary or traffic circle. Thanks for pointing out the reference as a rotary – I hadn’t noticed it.

    I guess my point (snarky as it may have been) was that those criticizing roundabouts because of this one are misguided. I wish PDOT would build a high-profile roundabout so folks could actually see how well they work. This is one area where progressive PDOT hasn’t been very progressive.

    If I got to pick a spot….I’d pick a tough one – the intersection of Naito Pkwy with the Ross Island Bridge.

  16. I heard someone suggest the 5-way intersection of 60th/Prescott/Cully.

    Although the intersection is primarily surrounded by parking lots, constructing the circle would probably require the destruction/relocation of a couple of commercial buildings and businesses, so it is understandable why there hasn’t been much momentum behind constructing a roundabout there.

  17. I wish PDOT would build a high-profile roundabout so folks could actually see how well they work.

    There are some modern roundabouts in the area (not PDOT though):

    -PDX Airport, at the entrances to the Economy lots, north of Airport Way.
    -In Washington County, 2 of them on Verboort Road north of Forest Grove.
    -Three in Sherwood, a nice one at Oregon & Murdock, and two on Meinecke Parkway, one each North and South of 99W.
    -On Carman Drive & Meadows Road South of Kruse Way in Lake Oswego.
    -Stafford Road at Rosemont Road. Clackamas County is building one at Wanker’s Corner at Stafford & Borland Roads (just north of the 205 interchange).
    -Two on Monterey Ave in Clackamas, at Causey and Stevens.

    If you’re up for a bit of a drive, Bend has the most extensive collection of roundabouts in the state. They have eliminated all traffic signals west of the Deschutes River. They have some fun variants like a dual roundabout and a two-legged roundabout. Bendites have these things figured out and drive them confidently.

    Springfield has been building a few, including a major new multilane roundabout at Pioneer Parkway & Hayden Bridge. Lacey, Washington (near Olympia) has been putting many in as well, including two at terminii of a new downtown couplet. Unit mentioned the Astoria roundabout, which is the first (only so far?) roundabout on the ODOT system, and also a multilane roundabout.

    39th & Glisan is emphatically not a roundabout, nor are those little neighborhood traffic circles on NW 25th or in eastside neighborhoods.

  18. I totally agree with Unit. 39th & Glisan vaguely looks like a roundabout, but is so poorly implemented that it is more of a problem than a solution. Someone should have lost their job over this design. A REAL roundabout would work great at that location.

  19. I should add:

    Most European roundabouts have the pedestrian crossings well BEFORE the circle, and sometimes regulated by a crosswalk light. In the case of 39th & Glisan, the bus stop locations totally screw this up. I guess someone felt that drivers can’t yield to pedestrians and cars at the same time so they put in a stop sign–the worst solution.

    This page covers roundabouts very well:

    http://www.wsdot.wa.gov/Projects/roundabouts/

    Please note the last photo. It shows a nearly perfect roundabout. The pedestrian crossings are positioned well before the merging area, which allows the driver to then focus on getting through the circle quickly and safely.

  20. When I lived down the street from this monstrosity of an intersection, the logic of placing stop signs at each intersection vs. a yield sign which is customary for a roundabout.

    By placing a stop sign, the city is encouraging a large amount of congestion and/or people to simply run the stop sign. Of course the city is busy funneling cash to pet projects like the streetcar and failing to adequately take care of failing roads so it’s no shock they are willing to imprison portlanders in traffic at this horrible intersection.

    It finally got to the point when on a motorcycle I would just ride it like it was meant to be with yield signs. Stop signs just made it worse. Someone in PDOT needs to grow a backbone and make the change back to a yield sign.

    Or a local residents needs to cut down the signs. People will figure it out.

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