NEWS RELEASE, 05/29/98
When it comes to speed bumps, passions run deep
and planning is paramount, says new UC Berkeley report
By Cathy Cockrell, Public Affairs
BERKELEY -- Never take a speed bump for granted.
When the needs of motorists and neighborhoods collide, finding the right fix can be complex and highly controversial, according to a new report from the University of California, Berkeley.
In Oakland, Calif., a woman lay down in the street to prevent the city from installing speed bumps on her block. In New Jersey, one man used a tow chain to destroy a despised concrete traffic diverter, while another dramatically dumped a truckload of dirt across an intersection to demand a barrier to control traffic.
UC Berkeley researchers Asha Weinstein, a PhD student in the Department of City and Regional Planning, and traffic planner Elizabeth Deakin, authors of the new report, believe local government can develop procedures to help minimize or resolve such conflicts. In addition, city administrators can learn from each other's past successes and mistakes to do better future traffic planning.
For their survey, the investigators interviewed traffic engineers and city planners around the country on their use of physical devices to tame auto traffic on neighborhood streets.
"A Survey of Traffic Calming Practices in the United States," published recently by the Institute of Urban and Regional Development, summarizes what the researchers learned.
"Lots of older cities were laid out in the era of the horse, not the auto," said Deakin, a UC
Berkeley associate professor of city and regional development, who chaired the City of Berkeley Transportation Commission for nine years.
In that city, for example, the last urban neighborhood was laid out in the early 1900s - when there were 6,000 registered vehicles in the state of California, versus 2 million today, said Deakin.
Although a grid of wide, straight streets afforded light and air in the era of gaslight and horse-drawn buggies, Deakin said, it is an invitation to speed for the person behind the wheel of a modern car.
"When the design environment says 'straight street, good view,'" said Deakin, "35 to 40 miles per hour feels comfortable" to a driver - but is often unacceptable to residents.
There are still, today, small towns in Europe and rural America where herding a flock of geese or sheep slowly up the center line works to slow down traffic.
But where flocks are few, a variety of other means have been tried - traffic circles, diverters, cul de sacs and islands - as well as those with names known primarily to traffic engineers: build-outs, chicanes, gateways, pinch points, over-run areas and rumble devices.
But first and foremost in the 1990s, the survey found, is the economical, easy-to-install speed bump.
"We were surprised by how many cities are involved in traffic calming," said Deakin, "and how ubiquitous speed bumps have become."
In England, where the bumps originated, they were called "sleeping policeman." That changed to "hump" when the bumps came to America, where the term "sleeping policemen" was thought to show disrespect for law enforcement. The term changed again, to "bump," in deference to those who blushed at the word hump.
After humps or bumps, "there was no clear winner," the report found. Many cities use traffic circles and diverters; a few have experimented with novelty signs, such as those in San Mateo County, Calif., that posts a 31.5 mile-per-hour speed limit.
Because problems often arise when traffic measures are introduced without adequate planning, the UC Berkeley researchers were interested in the procedures established in various cities to guide traffic calming decision making.
Of the 63 jurisdictions studied, only a handful, including Portland, Ore., and Seattle, Wash., routinely determine traffic calming measures as part of a neighborhood-wide plan. Most places surveyed still install such devices on a case-by-case basis.
Nearly two-thirds of jurisdictions surveyed have written traffic calming guidelines. Albuquerque, N.M., has a detailed 18-page brochure describing how to get a speed bump or diverter installed - including a petition process, impact assessment and a point system for prioritizing projects.
If that sounds like excessive red tape, the survey documents what can happen, on the other hand, when planning is absent or goes awry.
Traffic engineers in Phoenix, Ariz., describe a fiasco in the 1980s when they put turn restrictions on a collector street carrying local traffic to arterials, only to create a "nightmare situation" on adjacent local streets.
Thousand Oaks, Calif., at one time installed so many speed bumps that some critics started referring to it as the "city of a thousand humps," Deakin said. In Berkeley, as in a number of other cities around the country, the fire department objected to the proliferation of speed bumps, saying they impaired its ability to respond to emergencies. The city responded by declaring a temporary moratorium on new bump installation while it reevaluated its policies.
Annual budgets for traffic calming, the report found, ranged from a few thousand dollars in small towns such as Brea, Calif., to $2 million in Portland, Ore. Ten out of 63 communities studied had at least one staff person working full-time on traffic calming issues. In Houston, Texas, 15 employees devote a substantial part of their work week to traffic calming issues.
A few cities surveyed used traffic calming as part of their strategies to reduce crime. In the Dayton, Ohio, neighborhood of Five Oaks, as part of a $500,000 crime prevention program, streets and alleys were closed off.
"The neighborhood was restructured to create 10 mini-neighborhoods of three to six streets," the UC Berkeley report said, "and many of the internal streets were converted to cul-de-sacs."
Albuquerque reported another such experiment. "The idea," said the survey, "is to return the street to neighborhood territory through a variety of strategies, one of which is to make it unpleasant and/or confusing for outsiders to drive in the area."
Deakin and Weinstein plan to continue their research on traffic calming in order to formulate recommendations to improve traffic planning policies and procedures.
Send comments to: email@example.com