Driving while talking on a cellphone -- even a mobile with one of those ultra-fashionable hands-free devices -- is dangerous. We all know that; research suggests that the risk of getting into a scrape while talking on the phone is as high as that of driving with a blood-alcohol level of 0.08.
But it's not just my life you're risking when you dial up as you drive ahead of me. It is also, according to a new study, my time. You and your co-yappers are slowing down the whole road.
David Strayer, a psychologist at the University of Utah and an ardent investigator into the dangers of cell-addled driving, discovered this uneasy fact while observing 36 undergraduate students/research subjects maneuvering through a realistic police-driving simulator (these babies look rather awesome).
Strayer and his colleagues found that drivers who were on the phone were far less likely than other drivers to change lanes on the highway. This behavior slows the road -- research shows that traffic moves best when when fast drivers switch to faster lanes to avoid slower cars ahead.
Strayer put each test-subject driver into six different road scenarios: driving in low-, medium- and high-density traffic while not distracted, and driving those same conditions while using a hands-free mobile.
In each of these traffic conditions -- and especially when traffic was heavy -- drivers were able to move through the course faster if they changed lanes to avoid slow cars ahead.
But cellphoning drivers didn't move out from behind slow cars very often, or very fast; they were far more likely to stay poking along behind slower cars, and consequently took between 2 to 3 percent more time than non-distracted drivers to finish the simulated course.
That doesn't sound like much extra time, but consider that at any given moment, 10 percent of the drivers on the road are talking on the phone. If all these people are slowing down in order to take an important call, everyone else has to slow down too.
So traffic snarls. I miss my flight. But what do you care, right? Now that the road's a mess, you've got more time to chat.
Strayer's study, "Drivers' Lane Changing Behavior While Conversing on a Cell Phone in a Variable Density Simulated Highway Environment," prepared for the Transportation Research Board of the National Academies, is published online in PDF format here.
See his study comparing drunk drivers to phone-chatting drivers here, also as a PDF.