Wednesday, August 22, 2007

Riverside Roundabouts

During the Riverside Drive Vista Improvement Projects public deliberations, there was a woman who got up before council, visibly nervous, and poured her heart out with concern over the cities plans to install traffic roundabouts at specific intersections along riverside Drive. Now, I have experienced roundabouts both as a motorist and a cyclist, and have had no concerns about the saftey of these traffic calming/controlling devices, but she spoke with such emotion that I thought I would look back into this age-old method of controlling those motorised beasts.

I came upon this post from Spacing Wire, a heavily visited Toronto blog, that begs the same question: what kind of experiences have people had with modern day roundabouts?

Modern roundabouts have been popular in Britain since the 1950s and were adopted by other European countries during the 1980s and 1990s. More recently, they’ve been introduced, initially on a trial basis, to the United States and Canada. Those trials have proved so successful, not least in dispelling drivers’ fears of the strange circular junctions - remember when “The Simpsons” visited Britain only to find themselves driving around and around one? - that many more roundabouts are now being built.

“When construction started, there was a quite an outpouring of concern,” said Tom Adriance, highway superintendent of Malta, a town in upstate New York, where five roundabouts were recently completed and another seven are planned. “It was something new, and people were nervous. But as they’ve gotten used to the roundabouts, they’ve realized the benefits. The traffic moves quicker and flows pretty freely; very rarely is there any type of stacking or backup. Who wants to sit at a red light for two or three minutes?”

The success of the modern roundabout’s design is rooted partly in its structure and partly in its ability to modify motorists’ behavior by encouraging them to drive more slowly and considerately. It dates from the early 1900s, when William Phelps Eno designed Columbus Circle in New York as a “gyratory traffic circle” where vehicles drove around a central island. Across the Atlantic, his archrival, Eugène Hénard, was developing a similar idea around the Arc de Triomphe in Paris.
So, did this woman have any legitimate concerns, or was her reaction purely an emotional one based upon wives-tales and heresay? After a good 25 minutes of web browsing, I couldn't find one empiracle study that concludes that roundabouts are less safe than any of the other forms of traffic control devices that we are currently utlizing here in North America. There were some concerns regarding multi-lane roundabouts, but the proposal for Riverside Drive is only for one lane in each direction. These conclusions were echoed in the region of Waterloo:
Why do roundabouts have such a good safety record?

1. Fewer Conflicts. Roundabouts have fewer conflict points compared to conventional intersections. Roundabouts eliminate the potential for hazardous conflicts such as right-angle and left-turn head-on crashes. Roundabouts with single-lane approaches are safer than those with multilane approaches because of fewer potential conflicts between road users, and because pedestrian crossing distances are shorter.

2. Slower and more consistent speeds. Lower speeds in roundabouts allow drivers more time to react to potential conflicts, helping to make roundabouts safer. Most motorists travel at about the same speed through a roundabout, and that helps to reduce the crash severity compared to conventional intersections that mix slow and fast traffic.

3. Pedestrians cross one direction of traffic at a time. Pedestrians need only cross one direction of traffic at a time at each approach as they walk around a roundabout, compared with two-way traffic at most conventional intersections. There are just as many potential conflicts between vehicles and pedestrians at a roundabout compared to a conventional intersection, but at a roundabout the traffic all comes from the same direction where at a conventional intersection the pedestrian has to watch for traffic from all directions. In addition, motorists travel slower entering and exiting a roundabout compared to a conventional intersection. As with other road crossings where the pedestrian has to watch for a gap in traffic, roundabouts still present visually-impaired pedestrians with unique challenges.
So, I say that anything we can do to bring motorists and their 3,500 pounds of hurtling steel under control should generally be looked upon favourably.


Anonymous said...

i drive in europe every summer and let me tell you...i love roundabouts!! i keep trying to tell everyone that they are the way to go. they are so easy and eliminate needless idling at intersections. i've always wished we had more of them here.

Anonymous said...

...and hopefully we will, as long as hysterics doesn't rule over common sense.