Conventional, Forgiving Road Design Reduces Road Safety

By Dom Nozzi

Conventional “forgiving” road design strives to forgive bad drivers. Engineers who subscribe to conventional road design look at road crash data that shows many crashes have occurred due to excessive speed, or due to the driver using a cell phone, or putting on make-up.

The solution seems obvious: Design roads so that if the driver is driving too fast, or is using his cell phone, or is putting on her make-up, there will be less chance of a severe crash.

Unfortunately, this obvious solution results in less road safety. Why? Because conventional engineers have forgotten about human nature. If you design a road to forgive a driver for engaging in reckless driving, you encourage people to drive too fast and drive too inattentively. Human nature is such that most people drive at the highest speed that feels safe (regardless of what the speed limit sign says). Because we are so busy these days, we try to find more time in our day by driving faster and by multi-tasking (talking on a cell phone while driving, for example).

Engineers who have been designing the forgiving road for the past 60 years have therefore been busy widening roads, removing on-street parking, removing street trees, and pulling buildings away from the street — all in an effort to minimize the chance of a speeding, inattentive driver crashing into something.

But it does not take rocket science to realize that the forgiving road has the unintended consequence that most of us will drive more dangerously. We drive faster and more inattentively because we can do so more safely now. This is known by scholars in psychology as “risk homeostasis.” See, for rexample,

The solution is clear, yet counter-intuitive: We need to design roads so that we force drivers to pay attention and slow down. On such roads, a much smaller number of drivers will speed or talk on a cell phone, because it is too risky to do so on a street that is not forgiving. If you don’t pay attention, or if you speed, you will suffer consequences. On roads that are not forgiving, we breed more attentive drivers. And more skilled drivers.

Forgiving roads with too many “safety” features, by contrast, breed a decline in driving skill. It is therefore no surprise that there seems to be a large a growing number of drivers who drive poorly. Now we know why American drivers are among the worst drivers in the world.


Filed under Urban Design

2 responses to “Conventional, Forgiving Road Design Reduces Road Safety

  1. Robn

    Since they already have GPS units that can display the designated speed limit on roads all across America, then planners have the technology to interface the GPS data with a governor on vehicles. Let the public step on the gas as much as they want but have the actual vehicle speed be limited to the speed limit posted on the roads. Governors on trucks have been in use a long time. Designers need to use governor technology to put an end to driver irresponsibility. Advertisers need to stop showing ads that cause the public to want to step on the gas pedal and put it to the floor.

  2. Pingback: The Keys to Transportation Safety | Dom's Plan B Blog

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s