Credit for inventing speed bumps goes to the British. According to a publication put together by the Institute of Transportation Engineers (ITE), an international association of transportation planners, U.K. agencies in the early 1970s tested various designs before coming up with the "parabolic profile hump." It was soon picked up elsewhere in Europe and finally in this former colony; Federal Highway Administration testing of speed bumps began in St. Louis in 1979. By 1995 David Sucher, author of the book City Comfort--How to Build an Urban Village was calling traffic-calming "the most significant new idea in city planning." Cities in Florida, Oregon, California, and Washington were the first to try the technique, and hundreds more soon embraced it.
But, as with any new idea, the backlash inevitably came. In the past decade, a number of cities have removed speed bumps in response to public criticism. It happened in San Luis Obispo, where Terry Sanville is principal transportation planner: "We've had quite a few traffic-calming successes and some very tough failures," he says. "You've got to realize that when you put in speed bumps, you're going to hear from everyone: emergency-vehicle drivers, people who have sick relatives, plumbers who come to fix your pipes, people with RVs and large vehicles, garbage men, delivery people of all sorts. Neighborhoods that want to put them in had better be pretty certain about it." (A variety of anti-speed-bump reports are listed on the Web site of a national group called Americans Against Traffic Calming, www.io.com/~bumper/ada.htm).
Sanville says his department has now done its homework on speed bumps: "Studies, very scholarly studies, have been done--you know, how to slow people down without pissing them off. The newest reports say [a speed bump should measure] 12 to 14 feet at its base, about 212 inches at its highest point. They're not very abrupt, so they reduce the amount of jarring action. Motorists' derrieres are sensitive. Studies say drivers can tell the difference in height by a quarter-inch."
The pizza man can, anyway--and he can also tell a neighborhood that welcomes delivery drivers. As the Honda chatters along LaSalle Avenue, Donovan speculates on why Whittier, the Wedge's neighbor to the east, never embraced speed bumps. Maybe, he postulates, traffic-calming is an indicator of social status, which is why speed bumps are found chiefly in neighborhoods where people tip a dollar for a large pie and a Coke. Or maybe Sixth Ward city council member Jim Niland, who represents Whittier, is "the only guy in city hall who understands cars with screwed suspension."
Niland seems flattered by the theory. "There could be a class element to it in some sense," he offers. "Some speed bumps are paid for by assessing property owners, and rich neighborhoods probably have more of them." Then the council member reveals something Donovan seems to have known instinctively: He is a "brother of the road," as the pizza men say. "Before I was on the council, during college, I delivered for Rocky Rococo in La Crosse. So I certainly have sympathy for pizza-delivery drivers everywhere."
Eighth Ward City Council member Brian Herron never delivered pies, but he also believes in bump-free pavement. "We just have seasonal speed bumps on the alleys in my ward. I don't like them on the streets. And I've got a decent vehicle."
Herron has been an advocate, however, of altering the streetscape in other ways. He is among the initiators of an experiment near Chicago Avenue and Lake Street, where city engineers are trying out a technique they're calling "cul-de-sac-ing." Just east of the intersection, streets and alleys have been blocked off with construction barriers and orange pylons; in effect, drivers can't go south from Lake for three blocks. The barriers were installed in November, says Herron, in response to residents' complaints that customers from the liquor store and the rest of the busy corner brought drug dealers and prostitution into their streets. "Cul-de-sacs create a sense of one way in, one way out," explains Herron. "Most people with a criminal mindset don't like that they don't have an immediate escape route."
Underlying Herron's explanation is a philosophy called Crime Prevention Through Environmental Design, which in the past two decades has fueled a wave of street closings in cities across the nation. CPTED, explains a 1997 U.S. Department of Justice study, assumes that "many offenders are rational and will not commit crimes where they perceive the risks to outweigh the potential benefits." CPTED was popularized in the 1970s; one of the earliest studies supporting it was conducted in 1977 in St. Paul, where researchers found that through-streets experienced higher rates of burglary.
In the 1980s and 1990s, several dozen U.S. cities experimented with various degrees of CPTED-inspired street closings: Boston shut off pedestrian tunnels, Oakland and L.A. fenced and gated communities, and Charlotte limited auto access to a poor neighborhood. In Chicago, Mayor Richard Daley promised to "cul-de-sac the city."
Locally, the technique wasn't used until two years ago, when north Minneapolis's Willard-Hay neighborhood had barricades installed near the intersection of Broadway Street and Penn Avenue, home to a busy liquor store. Herron says he first considered the cul-de-sac concept because of the north-side project, which he says brought down crime rates and improved relationships between local businesses and residents. So far, he says, it seems to be working: "The feedback I get from residents is that, since the cul-de-sac, there's less hanging out at the liquor store, less trash, and drug traffic is down."