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Often when I’m driving, I find myself entering a difficult situation — a tricky lane-change, an unfamiliar turn — and I’ll actually ask my passenger (typically my wife) to essentially stop talking for a moment (or they will voluntarily do so) as the situation resolves itself. This, of course, is one of the major problems with talking on a cell phone versus talking with a passenger: Not only are they providing another set of helping eyes, but they can sense when would be good for them to modulate their conversation in some way, whereas the person on the other end of the cell-phone will seemingly keep droning on, taking away from the driver’s workload.

This point, fairly well established by now, is made again in a new study (PDF here) by Samuel G. Charlton, University of Waikato, Hamilton, for Land Transport New Zealand. The study, as others have, found that drivers on cell phones had slower reaction times — yet drove at higher average speeds — than drivers with passengers as they went through a number of hazards in a driving simulator. Interestingly, this study also featured a person on a cell-phone who was not present in the car yet had access to the driver’s view, so they have a passenger-like view of the road.

The key to performance seemed to be what the paper calls “conversation suppression,” i.e., knowing when to shut up: “Passengers talking to drivers made shorter utterances, had more frequent pauses and were more likely to be talking about the upcoming hazard than cellphone conversors. Drivers and their cellphone conversors tended to make longer utterances than the other participants, were less likely to mention the hazards, had the poorest recall of the hazards, and had the highest crash rate.” Even when the remote cell phone conversor had access to the driving scene, they didn’t tend to adjust their conversation as much as the passenger did — maybe there’s just something ineluctable in actually being there.

The study includes one other interesting, but to my mind a bit strange, finding. Drivers did a bit better on the cell phone when an automated hazard alert message “beeped through” their call, alerting them to some upcoming traffic hazard. This gave the driver the necessary cue to break off the conversation a bit. These alerts would presumably be triggered by some sort of beacons in the road infrastructure, particularly at hazardous points. But, of course, the thing about driving is one never knows when it’s going to become hazardous, and it certainly isn’t always at the accident “black spots” (which are often just statistical aberrations in any case). There are innumerable issues here, from a driver’s over-reliance on the hazard warning system, to the idea that they may be brought back “into the loop” with not enough time to react and not enough knowledge of the situation.

This entry was posted on Tuesday, August 12th, 2008 at 9:34 pm and is filed under Drivers, Traffic Psychology, Traffic Reports, Uncategorized. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.