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Passion Runs Deep When it Comes to Speed Bumps

by Cathy Cockrell, Public Affairs
posted July 15, 1998

Never take a speed bump for granted.

When the needs of motorists and neighborhoods collide, finding the right fix can be complex and controversial, according to a new report, "A Survey of Traffic Calming Practices in the United States," from the campus's Institute of Urban and Regional Development.

An Oakland 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 dumped a truckload of dirt across an intersection to demand a barrier to control traffic.

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 reduce or resolve such conflicts. And they think city administrators can learn from each other's experiences to better plan future traffic flow.

For their report, the researchers surveyed 63 jurisdictions, interviewing traffic engineers and city planners around the country on the use of physical devices to tame traffic on neighborhood streets.

"Lots of older cities were laid out in the era of the horse, not the auto," said Deakin, associate professor of city and regional development, who chaired the City of Berkeley Transportation Commission for nine years.

She says Berkeley's last urban neighborhood was laid out in the early 1900s -- when there were 6,000 registered vehicles in the state of California. Today there are 2 million.

Although a grid of wide, straight streets afforded light and air when gaslights and horse-drawn buggies were the norm, Deakin said, today such streets are an invitation to speed.

"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 small towns in Europe and rural America where herding a flock of geese or sheep slowly up the center line works to slow traffic.

But where flocks are few, other means have been tried, including traffic circles, diverters, cul de sacs and islands.Yet first and foremost in the 1990s, the survey reports, 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 policemen." That changed to "hump" in the U.S., where the term "sleeping policemen" was thought to be disrespectful to law enforcement. The term changed again, to "bump," in deference to those who blushed at "hump."

Weinstein and Deakin found that nearly two-thirds of the 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 setting priorities for projects.

If that sounds excessive, the survey documents the problems that can happen when planning is absent or goes awry.

In Berkeley, as in a number of other cities, when the fire department objected to speed bumps because they impaired its ability to respond to emergencies, the city declared a temporary moratorium on bump installation while it reevaluated its policies.

Deakin and Weinstein plan to continue their research so they can make recommendations for improving traffic planning policies and procedures.

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