"It's only a glance"

A glance is short. That's the whole case for it. Two seconds, eyes down, eyes up, and the road hasn't had time to change. Held against a crash, which is a big thing, a glance seems like nothing, and the belief that it's nothing is what lets you do it.

Here's what the research measures, and it's the glance itself. Bruce Simons-Morton and colleagues fitted the cars of forty-two newly licensed teenage drivers with cameras and sensors and recorded them for eighteen months. Then they looked at the six seconds before every crash and near-crash, and at random stretches of ordinary driving, and measured how long the driver's eyes were off the road ahead. The single longest glance was what mattered. When it went over two seconds, the odds of a crash or near-crash were 3.8 times higher across every kind of task, and 5.5 times higher when the task involved a phone. The longer the glance, the higher the risk, and it didn't matter what the glance was for.

Those were teenagers, and you'll want to know about adults. Sheila Klauer and colleagues ran the same kind of study with the same forty-two novices alongside a hundred and nine experienced drivers, and published it in the New England Journal of Medicine. For the novices, dialling a phone raised the odds of a crash or near-crash by more than eight times, and reaching for one by seven. For the experienced drivers, dialling raised it by two and a half times. Texting wasn't assessed in the experienced group, so I can't give you that figure, and I won't make one up. What I can say is that experience shrank the number and didn't remove it.

Now the arithmetic, which is mine. At thirty miles an hour you cover about thirteen metres a second. A two-second glance is twenty-seven metres of road you didn't see, which is about six car lengths. At fifty it's forty-five metres. The glance feels like nothing because nothing was there in the twenty-seven metres, this time, and the road doesn't send a reminder when something was nearly there.

Jeff Caird and colleagues pulled together twenty-eight experiments on texting while driving, nearly a thousand participants between them, and found that reading and typing messages affected everything they measured. Where the eyes went, what got noticed, how fast people reacted, how well they stayed in lane, how close they followed. Reading alone did less damage than typing, and it still did some. The glance isn't nothing. It's a measured thing with a measured cost, and the reason it feels like nothing is the subject of the next three chapters.