Ruly Bookshelf: Traffic: Why We Drive the Way We Do

This month’s Ruly Bookshelf choice will challenge everything you know about traffic and driving. Traffic: Why We Drive the Way We Do (and What It Says About Us) by Tom Vanderbilt is a detailed research study about how the human brain processes the challenges of interacting with other road users.

It should not be too surprising to learn that humans aren’t really designed for the physical and mental challenges of driving.

“You may be wondering how it is that humans can even do things like drive cars or fly planes, moving at speeds well beyond that ever experienced in evolutionary history. . . . The short answer is that we cheat. We make the driving environment as simple as possible, with smooth, wide roads marked by enormous signs and white lines that are purposely placed far apart to trick us into thinking we are not moving as fast as we are. It is a toddler’s view of the world, a landscape of outsized, brightly colored objects and flashing lights, with harnesses and safety barriers that protect us as we exceed our own underdeveloped capabilities.”

–Tom Vanderbilt, Traffic: Why We Drive the Way We Do

This book is chock-full of psychological phenomena that describe why humans aren’t very good at practically any aspect of driving. We don’t estimate our rate of speed well. We are not very good judges of the speed other vehicles approach us. We don’t relate appropriately to other people in traffic. We dehumanize drivers of other cars and don’t respect drivers of non-car vehicles, like bicyclists, motorcyclists and commercial trucks.

“Traffic messes with our heads in a strangely paradoxical way: We act too human, we do not act human enough.”

–Tom Vanderbilt, Traffic: Why We Drive the Way We Do

Human behavior on the road is counterintuitive and bizarre. Traffic scientists have given these scenarios creative names. For example:

• “moth effect” – Drivers attracted by the flashing lights of emergency vehicles stopped by the side of the road end up crashing into them.
• “treadmill effect” – After driving at a high rate of speed, when you slow down to a lower speed, your brain tells you that you are driving much more slowly than you really are–much like the effect one gets after running on a treadmill and feels like one is moving backward.
• “empty lane syndrome.” – “Solo drivers sitting in a highly congested lane may look to the HOV lane next to them and think that it’s empty . . . . Many times it just seems empty because of the large headways between vehicles moving at much higher speeds. That lane may actually be achieving the same volume as the lane you are in . . . “
• “girlfriend effect” – Men drive more safely with women in their car, whether the woman is a romantic partner or not.

There are many lessons in this book about situations that increase our risk of causing an accident. For example:

• More than two seconds looking away from the roadway significantly increases your chance of accident.
• When talking on a cell phone while driving, our eyes tend to fixate on a single point right in front of our own car rather than glancing in various directions to take in all the information about our environment. The distraction of processing the voice on the other end of the line significantly increases our risk of accident, whether we are talking “hands-free” or not.
• “Drivers seated at higher eye heights but not shown a speedometer will drive faster than those at lower heights. . . . Studies have shown, perhaps not surprisingly, that SUV and pickup drivers speed more than others.”
• “There is, in theory, nothing nicer than a drive in the country, away from the ‘crazy traffic’ of the city. But there is also nothing more dangerous. . . . Rural interstate roads have a death rate more than two and a half times higher than all other roads. . . . Taking a curve on a rural, noninterstate road is more than six times as dangerous as doing so on any other road.”
• “[The pickup truck is] the most dangerous vehicle on the road: More people in the United States dies in pickups per 100 million vehicles registered than in any other kind of vehicle. Pickups also impose the most risk on drivers of other vehicles.”
• The number one cause of traffic fatalities is single-vehicle run-off road” accidents where people zone out or fall asleep at the wheel.

Mr. Vanderbilt studies traffic from a variety of angles and travels around the world to learn how other countries study their own traffic problems. After reading his description of Delhi traffic, I had to see it for myself.  I found this video on YouTube of a person crossing the street in India demonstrating the huge number of vehicles of various types, including pedestrians, motorcycles, bicycles that all mix together, often without any traffic signals!

Another concept Mr. Vanderbilt looks at is the Dutch woonerven where they have designed their residential streets to be very narrow and have children’s play areas and gardens right near the street! While this sounds crazy, apparently drivers take their visual cues to slow down because the street scene is cluttered and dangerous. Below is a video showing an example of a street in a residential neighborhood in Delft.

In contrast, the typical U.S. residential street is prone to speeding because we have large, flat roadways with perhaps only an ineffectual “25 Miles Per Hour” or “Children at Play” sign.

While Mr. Vanderbilt doesn’t offer a lot in terms of suggestions to improve our driving or risk of accident, his primary message seems to be that we all need to slow down. Roads need to be designed not to be flat and straight but with enough mental challenges like curves to keep drivers awake and focused. He also suggests our driver education program could perhaps use a boost from professional driving courses that help us understand the physics of situations like “understeer.”

This book is a bit research and science dense and takes a little effort to get through but is a fascinating read for anyone who does a lot of driving.  I think it would also make a great PBS special.

Are you surprised by any of the driving phenomena mentioned above? Have you experienced any of these situations? Please share in the comments.