April 9, 2008.
California Office of Traffic Safety Summit
San Francisco, CA.
May 19, 2009
University of Minnesota Center for Transportation Studies
Bloomington, MN
June 23, 2009
Driving Assessment 2009
Big Sky, Montana
June 26, 2009
PRI World Congress
Rotterdam, The Netherlands
June 27, 2009
Day of Architecture
Utrecht, The Netherlands
July 13, 2009
Association of Transportation Safety Information Professionals (ATSIP)
Phoenix, AZ.
August 12-14
Texas Department of Transportation “Save a Life Summit”
San Antonio, Texas
September 2, 2009
Governors Highway Safety Association Annual Meeting
Savannah, Georgia
September 11, 2009
Oregon Transportation Summit
Portland, Oregon
October 8
Honda R&D Americas
Raymond, Ohio
October 10-11
INFORMS Roundtable
San Diego, CA
October 21, 2009
California State University-San Bernardino, Leonard Transportation Center
San Bernardino, CA
November 5
Southern New England Planning Association Planning Conference
Uncasville, Connecticut
January 6
Texas Transportation Forum
Austin, TX
January 19
Yale University
(with Donald Shoup; details to come)
Monday, February 22
Yale University School of Architecture
Eero Saarinen Lecture
Friday, March 19
University of Delaware
Delaware Center for Transportation
April 5-7
University of Utah
Salt Lake City
McMurrin Lectureship
April 19
International Bridge, Tunnel and Turnpike Association (Organization Management Workshop)
Austin, Texas
Monday, April 26
Edmonton Traffic Safety Conference
Edmonton, Canada
Monday, June 7
Canadian Association of Road Safety Professionals
Niagara Falls, Ontario
Wednesday, July 6
Fondo de Prevención Vial
Bogotá, Colombia
Tuesday, August 31
Royal Automobile Club
Perth, Australia
Wednesday, September 1
Australasian Road Safety Conference
Canberra, Australia
Wednesday, September 22
Wisconsin Department of Transportation’s
Traffic Incident Management Enhancement Program
Statewide Conference
Wisconsin Dells, WI
Wednesday, October 20
Rutgers University
Center for Advanced Infrastructure and Transportation
Piscataway, NJ
Tuesday, March 8, 2011
Ontario Injury Prevention Resource Centre
Injury Prevention Forum
Toronto
Monday, May 2
Idaho Public Driver Education Conference
Boise, Idaho
Tuesday, June 2, 2011
California Association of Cities
Costa Mesa, California
Sunday, August 21, 2011
American Association of Motor Vehicle Administrators
Milwaukee, Wisconsin
Wednesday, October 26, 2011
Attitudes: Iniciativa Social de Audi
Madrid, Spain
April 16, 2012
Institute for Sensible Transport Seminar
Gardens Theatre, QUT
Brisbane, Australia
April 17, 2012
Institute for Sensible Transport Seminar
Centennial Plaza, Sydney
Sydney, Australia
April 19, 2012
Institute for Sensible Transport Seminar
Melbourne Town Hall
Melbourne, Australia
January 30, 2013
University of Minnesota City Engineers Association Meeting
Minneapolis, MN
January 31, 2013
Metropolis and Mobile Life
School of Architecture, University of Toronto
February 22, 2013
ISL Engineering
Edmonton, Canada
March 1, 2013
Australian Road Summit
Melbourne, Australia
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September 9th, 2010 at 9:25 am
In Massachusetts where I am from, roundabouts (or rotaries as we call them) are quite common. I like them personally and think they are quite efficient when everyone understands the rules and is basically courteous, but when a confused driver from out of state meets an aggressive “Masshole,” the rotary can cause more delays and potential accidents than typical intersections.
September 9th, 2010 at 9:47 am
Solutions like that are reasonably common in the Netherlands. They’re referred to as ‘botonde’ (a pun on the Dutch words for ‘bone’ and ’roundabout’)
The most common and most obvious use is at motorway exits, spanning over (or under) the motorway; in such circumstances, the roundabouts are not completely circumnavigable as the motorway ramps are all one-way and thus certain movements are not necessary. This effectively combines both roundabouts into a single one.
A picture is worth a thousand words, so here’s a example to be built in Amsterdam:
http://www.noordwaarts.nl/projecten/can/infrastructuur
Other botondes provide a full roundabout on only one side:
http://maps.google.nl/maps?ll=53.199966,6.510429&t=h&z=18
http://maps.google.nl/maps?ll=52.163344,4.558597&t=h&z=17
Or how about a botonde linked to a regular roundabout:
http://maps.google.nl/maps?ll=52.199309,4.612858&t=h&z=18
Note that in this last example, a car coming off Achterweg in the north and wishing to travel east would have to go all the way around both roundabouts. As is common around here, directness of journey for motor vehicles is not considered as important as things like safety, segregation, air quality and noise. Detouring cars a few hundred metres or sometimes even kilometres to avoid a residential area or potentially dangerous junction is considered acceptable.
September 9th, 2010 at 11:02 am
1. In france they have to remind people to give way at roundabouts, because the normal rule “priorite a droite” doesn’t apply. Search for images of “vous n’avez pas la priorite” to see.
2. There are in Bristol some places with two small “mini roundabouts” right after the other. They can be tricky as a lot of people will come out of one junction -with right of way- and are suddenly in a position without the right of way. The usual “one move lookahead” horizon effect kicks in, with trouble all round. I think to work best you need a minimum distance between roundabouts (measured in time between decisions) for safe use. Here’s a link to the satellite view
http://maps.google.co.uk/maps?f=q&source=s_q&hl=en&geocode=&sll=51.456815,-2.608931&sspn=0.008116,0.014291&ie=UTF8&hq=&ll=51.457595,-2.612777&spn=0.001014,0.001786&t=h&z=19
3. We have some lovely photographs up on Bristol Traffic of a mini-roundabout deadlock occurring
http://bristolcars.blogspot.com/2008/12/roundabout-failure.html
while roundabouts do promise maximum throughput, they require on balanced exits and entries to every lane: if nobody exits onto your road, you don’t get a go. If everybody exits onto one road, the capacity becomes limited to that road’s throughput, and can trigger jams which block the roundabout altogether. You might think in the photo those cars are being selfish or short-sighted by pulling out and blocking the roundabout, but they know that if they don’t pull out, that they won’t get a chance for many minutes anyway -so they have nothing to lose.
September 9th, 2010 at 11:58 am
Eric,
It’s important to note that a roundabout and a rotary are not usually the same thing. Rotaries are usually larger, higher speed and don’t have much in the way of pavement markings. Roundabouts are smaller, lower-speed, and are clearly marked, making them more efficient and safer for cars as well as more hospitable for pedestrians and bicyclists. We do have a few roundabouts in Massachusetts, but not many, although more are being built.
September 9th, 2010 at 12:37 pm
There’s a similar figure 8 in the Fresh Pond- Alewife area of Cambridge MA. In that case, the two rotaries are spaced maybe 1/8 mile apart (maybe not even that far) within easy sight distance of each other, but not quite as close as those shown above. That area handles a huge volume of commuter traffic in the mornings and evenings, and although it backs up pretty badly, I think it’s the fault of the downstream signals more than the rotaries.
September 9th, 2010 at 12:58 pm
The double roundabout configuration is uncommon, but not necessarily rare. It’s also just as easy to navigate as a single roundabout: they’re just two individual roundabouts albeit with a short connection in between.
Also, roundabouts (different from circles & rotaries) tend to have overall reductions in crashes as compared to signals; and any crashes that do occur tend to be of significantly reduced severity owing to the lower travel speeds as well as similar movement paths at the collision point.
September 9th, 2010 at 2:29 pm
Not only do we have a “Figure 8 roundabout” here in Anchorage, AK, but it is also a figure-eight roundabout with DOUBLE LANES for added measure! (www.alaskaroundabouts.com/Dowling). While the jury is still out regarding the safety of the double-lane double-roundabout configuration, accidents at this intersection seem to have spiked since the intersections were modified. A news report captured one accident during an on-site filming for a story about the “second most dangerous intersection in Anchorage”(www.adn.com/2009/09/15/935836/crunch-time-in-the-dowling-road.html).
From what I can tell, the main problem is drivers get confused about which lane, the inside lane or outside lane, has the right-of-way when turning through the east and west ends of the figure-eight configuration. A humurous aside: there are at least 3 autobody shops located within 300 yards of this intersection.
September 9th, 2010 at 5:17 pm
I’ve seen similar double roundabouts in Colorado somewhere, though I can’t remember where exactly…
September 9th, 2010 at 5:42 pm
I’ll see your doubles and raise you one. Metro Detroit has a triple roundabout — some which have two lanes — compliments of MDOT. It’s horrific in a car, impassable on foot, and death on a bike. The only time I’ve gone through it correctly was at 6am on a weekend when I could ignore all the signs and just drive where I wanted to go.
http://maps.google.com/maps?hl=en&ie=UTF8&hq=&hnear=Detroit,+Wayne,+Michigan&ll=42.506108,-83.759884&spn=0.010488,0.012875&z=17
I just looked at the crash stats. There were 78 reported crashes on the western roundabout and 19 on the eastern roundabout in 2009 alone.
September 9th, 2010 at 8:38 pm
I don’t like it. It is terrible for automobiles, worse for bicycles, and horrible for pedestrians.
Maybe if every aspect of this plan were smaller it may have been okay. Someone told me the red area is not normally for driving on but people do anyway and it is helpful for large trucks – have not witnessed that, but I have seen confused automobile drivers on the red area.
Buffalo
September 10th, 2010 at 4:38 pm
Contrary to popular belief a ‘well designed’ roundabout.
1) Has better throughput that a signalized intersection or stop signs while reducing top speeds (speed kills).
2) Has fewer and less much less severe accidents than signalized.
3) Can be designed to be safer for pedestrians than signalized (cross on direction of traffic at a time).
Go to roundaboutsusa.com for more details.
Read traffic.
Look at what Carmel Indiana has been doing with roundabouts and ‘dog bone roundabouts’ at freeway junctions with surface streets.
George C
September 11th, 2010 at 10:43 pm
Caltrans installed a pair of roundabouts about 5 years ago in Truckee, CA, where Highway 89 passes under Interstate 80. These circles are a tremendous improvement over the previous and inefficient system of off & on ramps and center turning lanes that used to back up cars for miles on holiday weekends.
Location:
http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=truckee,+ca&sll=37.0625,-95.677068&sspn=31.28862,59.765625&ie=UTF8&hq=&hnear=Truckee,+Nevada,+California&t=h&ll=39.323293,-120.211308&spn=0.007453,0.022767&z=16
Sierra Sun article:
http://www.sierrasun.com/article/20051223/NEWS/51222004
September 14th, 2010 at 5:53 am
The examples bz2 shows leave out unnecessary parts of the roundabout, which makes it more safe and easier to navigate the roundabouts, especially at a diamond interchange.
October 8th, 2010 at 3:51 pm
No. To really experience roundabout mayhem, you need to visit Swindon.