Seattle Traffic Calming

"Slow Down, You're Going Too Fast: The Community Guide to Traffic Calming" is a collection of stories from municipalities nationwide.

This study, posted apparently in full on the web site of Public Technology Inc., the non-profit technology research, development and commercialization organization for all cities and counties in the United States, "helps local elected and appointed officials and civic groups understand the ins and outs of traffic calming." The introduction declares that, "This success story booklet highlights thirty examples of traffic calming strategies in the U.S., Canada, and abroad." However, at least in the version posted on the website, the report lacks references, and the authors appear unaware of the many published studies examining the accident reductions achieved (or not) by various traffic calming schemes.

The 'traffic calming success stories' in this interview collection are wildly different approaches. San Jose, California, is cited as a traffic calming success for abandoning its program due to 'budget difficulties' while launching a billion dollar freeway expansion program. A success? This year, Santa Clara County, of which San Jose makes half the population, was cited in the National Mean Streets Report as the California's most dangerous for pedestrians. However, Case study #20, of Seattle, Washington, does provide this overview of traffic circles:

They are as common to Seattle as Starbuck's and rain: Traffic circles.

A transportation planner in Oregon muses that "they give them out up there like they're going out of style."

Seattle gets "a huge request for traffic circles," says Ellie Rangel, city traffic technician, and it doles them out generously. More than 600 traffic circles have been installed since 1978 as part of the city's traffic calming program, at a rate of 10 to 30 each year. Still, it hardly meets the demand: Seattle Transportation receives 600 to 700 requests per year for circles.

After Seattle became known as one of the the most liveable cities and the economy flourished, the population of both humans and cars swelled. The main areas of complaint usually are within a block of an arterial road. Circles are installed mostly on residential streets, Rangel says, and placing two or three circles in a row is "very effective." A handful have been placed on collector arterials, as Seattle calls them, but those collector roads operate as residential streets.

Most circles are 16 to 20 feet wide for 25-feet-wide streets, just large enough to divert and slow the traffic. Each costs about $6,000 on a concrete road surface, and $4,500 on asphalt. Although that's a bargain compared to $25,000 to $100,000 for a traffic signal, which some neighborhoods have requested, the real savings is collision reduction, says Jim Mundell, senior engineer.

Of 119 locations surveyed, the city found a 94 percent reduction in accidents, saving citizens $5.5 million in damages. Mundell calls that a "tenfold return on your investment."

Another hidden but important issue, he says, is stop signs vs. traffic circles. Many citizens and elected officials often ask for stop signs as quick and cheap $200 to $300 each solutions to slowing speeders.

"We don't feel that's the answer for traffic control," Mundell says. "Nobody stops for stop signs.

At stop signs, motorists try to make up for lost speed by gunning through the intersection. Nearby residents have to listen to grinding transmissions and screeching brakes.

The City Council has funded circles, pedestrian walkways, circular bulbs, partial closures of streets and 'do not enter' signs. One program asks residents to match the city's money. Another allows them to work off some of the cost, such as doing their own landscaping on traffic circles rather than using city workers and money to do it.

"We try to landscape everything we build," Mundell says. "It's very important. Rather than just paving another piece of the road, we've created a green space."

Besides enhancing the neighborhood, the green space limits sight distances, which lowers speeds. And neighborhoods welcome the traffic calming circles if they like the way it looks.

To those commuters who rue the traffic calmed streets, Rangel says calmly, "Maybe they'll find another route if they are hindered by the one they are using."

Contact: Jim Mundell Seattle Transportation 206/684-0814

Seattle, population 1.9 million in metropolitan area, at 84 square miles is the largest city in the Pacific Northwest.