Drivers, don't take that call: You may regret it

When it comes to driving, not all conversations are alike.

A recent study by psychologists at the University of Utah found that drivers talking on cell phones made significantly more driving errors than those who talked in person to passengers.

The researchers paired 41 drivers with friends. Participants ranged in age from 18 to 49, but most were young (the average age was 20), with men and women about equally represented.

During each of three experimental conditions, one member of the pair was randomly chosen to be the driver and the other was designated the partner. During each experiment, the driver operated a driving simulator that not only mimicked actual traffic conditions but also measured aspects of driving performance.

In the first experiment, the driver used a hands-free cell phone to talk with the conversation partner, who was located elsewhere. In the second experiment, the driver and passenger talked while seated next to each other in the driving simulator. In the third experiment, the two sat next to one another but did not talk.

Drivers holding conversations by cell phone were four times as likely to miss pulling off at a rest area (as previously instructed) as those talking to passengers in person. The cell phone users were also more likely than the others to drift in their lanes and to keep more distance between their cars and those in front of them.

The researchers speculate that driving while talking on a cell phone may make it harder for someone to process external information and concentrate on driving conditions - a condition they termed "inattention blindness."