Statistically speaking, more than half of all traffic accidents happen at intersections, because that’s where vehicles and pedestrians cross paths most often. But crosswalks themselves are especially controversial in traffic-engineering circles because they don’t always make the road safer for pedestrians. Quite the opposite, in fact.
Regarding statute 169.21—the law I refuse to obey—several studies have shown that providing pedestrians with a painted crosswalk at otherwise unmarked intersections, particularly those that cross more than two lanes and involve high traffic volumes, can be more dangerous than having no street markings at all.
The most-often cited reason for this uptick in danger is the false sense of security crosswalks appear to provide in the pedestrian’s mind. Crosswalks give pedestrians a sense of “ownership” over the road, according to a five-year study done by the U.S. Department of Transportation involving 1,000 marked and 1,000 unmarked intersections. Apparently, pedestrians interpret those few white stripes on the pavement as a kind of invisible force field that repels oncoming traffic, which gives them a false sense of security that makes them take fewer precautions than they should.
“There’s nothing magic about a crosswalk,” says Paul St. Martin, St. Paul’s head traffic engineer. “Folks who think that once you stripe the road people are going to automatically stop are kidding themselves.”
In traffic-engineering parlance, the driving situation that vexes me is called a “multiple-threat” crash scenario, because there are at least three actors involved: the pedestrian, the stopped car, and the car that won’t stop. In the USDOT study, almost 20 percent of all crashes in marked, uncontrolled intersections resulted from a pedestrian walking in front of a stopped car, only to be plowed down by a car in the adjacent lane that didn’t stop. In that same study, at identical intersections without a marked crosswalk, there were no multiple-threat crashes. None.
It’s not hard to see why. Drivers are more likely to stop for pedestrians at marked crosswalks, setting up the one-two punch in the first place. And pedestrians are more likely to cross in front of a stopped car at a marked intersection. If the intersection has no marked crosswalk, pedestrians tend to have a healthier respect for—and distrust of—oncoming motorists.
“Pedestrians have to realize that it’s a lot easier for them to see motorists than it is for motorists to see them, especially at night or under adverse weather conditions,” cautions Nathan Bowie of the Department of Public Safety. “It’s the pedestrian’s responsibility to cross with caution, just like it’s the driver’s responsibility to look out for pedestrians.”
Speed and traffic volume are also important factors. Forty miles per hour appears to be the magic number around which many traffic-engineering decisions are made. Motorists are much more likely to stop for pedestrians if they are going less than 40 miles per hour, and almost certain to stop if they are going 20 miles per hour or less.
Speed is also important because, according to the National Highway Traffic and Safety Administration, pedestrians hit by a car traveling 40 miles per hour have an 85 percent chance of dying. The death rate drops dramatically from there. A pedestrian hit by a car traveling 30 miles per hour dies only 45 percent of the time. At 20 miles per hour it’s less than 5 percent.
The physics of a two-ton automobile hitting a human being are complicated and depend on many factors, such as the weight and speed of the car, the height of the car’s bumper, the height and weight of the person being hit, and so on. The main reason people tend to die if they get hit by a standard-size car going 40 miles per hour is that the bumper clips them at the knees, their feet fly out from underneath them, their torso goes horizontal, and their head smashes into the windshield. At less than 40 miles per hour, a person’s head is less likely to hit the windshield and the person is much more likely to roll off to one side or the other, where the chances of getting seriously injured decrease according to the speed at which they are hit. (Many cars now have rounded front ends not only for style reasons, but because a rounded front bumper increases the likelihood that someone hit by that car will roll off and away from the car rather than get pegged to the grill or smashed by a square corner.) Some countries—Germany, Finland, and Norway among them—don’t allow crosswalks at all on multiple-lane roads where the speed limit is higher than 40 miles per hour. Why? Because it’s the easiest way to eliminate unnecessary deaths.