Phone conversations distract drivers more than passengers

By John Timmer | Published: December 01, 2008 - 11:52AM CT

Human beings have a finite capacity for working memory, which tracks a limited number of items for the short periods of time it takes to complete the task at hand. So it's no surprise that many studies have found that cell phone conversations have a serious impact on driving skills, in some ways comparable to that of alcohol. A cursory analysis would suggest that all conversations should be equally distracting, but real-world experience shows that this isn't the case—it appears that passengers actually improve the performance of the people driving them about. A new study gets into the reasons for this discrepancy.

The introduction to the study describes a variety of previous work that describe at least three aspects of driving that appear to be negatively impacted by cell phone use. The first is basic control; drivers on cell phones have a pronounced tendency to drift around in (and potentially out of) the lane they're occupying. The second is tactical, which involves adjusting to the cars around you on the road through activities like maintaining a braking distance. Finally, studies have shown that drivers engaged in cell phone conversations are bad at strategic or task-focused processes, such as actually getting to their intended destination.

In the view of the new study's authors, there are two major issues with this past work. The first is that the prior studies simulate both driving and conversation with varying degrees of accuracy. But the second is that real-world data suggests that not all conversations are created equal. Epidemiological studies of auto accidents suggest that cell phone usage quadruples the risk of getting involved in a crash; in contrast, having an adult passenger in a vehicle actually reduces the chances of being involved in an accident.

Full Story:

http://arstechnica.com/news.ars/post/20081201-for-drivers-passenger-and-phone-conversations-arent-equal.html

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