Features

Walk Don’t Walk

To prevent killing pedestrians, does it sometimes make more sense to break the law than obey it?

Walk Don’t Walk
Photo Illustration by Randall Nelson
Will the driver in the red car stop, or won’t he? Everything hangs in the balance.

Google to the Rescue

Could technology eventually stop driver/pedestrian crashes altogether?
California recently passed a law allowing Google to test a small fleet of computer-controlled Toyota Priuses in regular traffic. The cars use a combination of radar, sensor, and video technology to navigate the roads. Google claims that, so far, the cars have driven more than 300,000 miles without an accident. The technology is so reliable that, by some estimates, 70 percent of cars on the road in 2040 will be computer-controlled.  

 

Giving up control of a vehicle might make some people squeamish, but if statistics confirm that driverless cars are indeed safer—and insurance companies end up pushing for it—Google-controlled traffic could be a reality sooner than you think.
 

The Psychology of Risk

Why even the most well- intentioned safety efforts backfire.
The idea that some “safety” measures actually make a situation more dangerous is one civic engineers live with every day. Two similar but different psychological paradoxes come into play in these situations. One is perceived risk versus actual risk; the other is known as “risk homeostasis.”  

 

Traffic lights are a good example of perceived risk versus actual risk. Most people believe that traffic lights are safer at intersections than stop signs, but that’s often not the case. Traffic lights make some intersections more dangerous because they introduce variables and behaviors that don’t exist at intersections with just a stop sign: people who shoot through yellow lights, over-zealous left turners, pedestrians trying to beat the “Don’t Walk” sign, less attention on what cars are actually doing.

At intersections with stop signs, however, both drivers and pedestrians tend to pay more attention to what everyone else is doing, and they have fewer accidents because of it. “Risk homeostasis” is what happens when people see better safety measures as an invitation to take greater risks. Not many people would voluntarily jump off a bridge, for example. But strap sturdy boots to their ankles and cushion their descent with a giant rubber band, and suddenly you’ve got a popular sport: bungee-jumping.

Applied to driving, risk homeostasis is what happens when drivers see better safety measures—road improvements, safer cars, and so on—as an opportunity to drive more dangerously. They might view the ubiquitous crosswalk-countdown clock—the one that goes “10, 9, 8 . . .” as a device that informs them precisely how close they can shave their last-second punch through an intersection.In the larger view, however, risk homeostasis is the annoyingly counterintuitive property of good intentions with which the road to hell is paved.  

A rise in pedestrian fatalities in Minnesota at a time when every other type of traffic fatality is on the decline led to the creation of the Share the Road safety campaign.

 

A rise in pedestrian fatalities in Minnesota at a time when every other type of traffic fatality is on the decline led to the creation of the Share the Road safety campaign.

 

Minnesota Safety Facts

  • Number of pedestrians killed in 2012: 38
  • Number of pedestrians injured in 2012: 876
  • Percent of pedestrian fatalities that are men: 73%
  • Pedestrian fatalities caused by failure of a driver to yield: 35%
  • Percent of pedestrian crashes that result in death: 5%
  • Percent of car crashes that result in death: .5%
  • Chances of dying if you are hit by a car going 20 mph: 5% > at 30 mph: 45% > at 40 mph: 85%
  • Sources: MNDot, USDOT


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