I'm not sure they've scientifically identified what the difference is, only that there is one, and multiple studies have confirmed it. Theories include the passenger having some awareness of road conditions and shutting up or even alerting the driver; or psychological factors that say the driver isn't "removing" her consciousness from inside the car.
There are specific behaviors that are stereotypical of people driving on the phone, and most of them relate to tunnel vision. I don't encourage anyone to talk while driving, but if you do it and you're not aware of the tunnel vision you get, you might just give it a try on a flat, straight, untrafficked piece of road. Start talking to someone. (Dial hands free or while you're stopped.) Make sure they know you're doing an experiment and that they're prepared for you to drop the phone at any second. Now make sure you're seeing with your whole eyes. Keep your eyes on the road and (while talking to the person about something ELSE), identify everything in your peripheral vision and predict what it's going to do and/or where hazards might be coming from.
Betcha can't do it. I sure can't. That's why you'll usually see people on the phone "attaching" themselves to other vehicles - either by tailgating or by shadowing someone's blind spot. They can only really see one thing while they're talking and driving, so they attach themselves to another vehicle and do whatever the other driver does.
It can be tough sometimes trying to shake a phone addict when you're driving the car they're attached to!
I'll add that I think it's the tunnel vision that makes phone addicts especially dangerous to us cyclists and runners, because it exacerbates target fixation. As a motorcyclist and bicyclist, I'm well aware of target fixation (both in myself and in other drivers), but it wasn't until I started running (facing traffic) that I really became aware of how enormous a problem it is and how ill-educated most drivers are about it. When a driver can only see one thing (tunnel vision), and then that thing becomes YOU (because they're suddenly looking at something they're not used to seeing on the road) and then they AIM for you (because tunnel vision plus target fixation means they can literally only drive in the direction they can see in - BTDT myself [not on the phone], totalled my moto but luckily only got some bruises and didn't hurt the other driver) - that's how cyclists and little kids walking to school die. Right? You read all the time how somebody got run over on the shoulder or even on the sidewalk, and the police report says "it's unknown why the driver left the roadway," when in fact it's perfectly obvious why the driver left the roadway. Target fixation. Not necessarily involving a phone, but phones seriously exacerbate it.
This is drifty, but it's important. Please. Seriously. You're not just endangering yourselves - but your own safety is valuable, too, and we'd miss you.
Last edited by OakLeaf; 10-30-2011 at 05:39 AM.
Speed comes from what you put behind you. - Judi Ketteler