Drivers use their cellphones more when speeding, telematics data show (IIHS)

Drivers are more likely to use their phones while speeding, a tendency that increases crash risk by combining two dangerous behaviors, according to a new study from the Insurance Institute for Highway Safety (IIHS).

“Until now, safety experts believed drivers used their cellphones most at slower speeds,” said IIHS President David Harkey. “But data from safe-driving apps show that, in free-flowing traffic, the opposite is true.”

Excluding time spent stopped at intersections, mired in traffic and driving small neighborhood streets, the amount that drivers handled their phones increased the more they exceeded the speed limit, a nationwide analysis of cellphone data showed.

On limited-access roads, the share of driving time spent handling a phone rose by 12% for every 5 mph drivers went over the local speed limit. Limited-access roads are freeways and other roads where vehicles enter and exit only via on- and off-ramps.

On other roads, such as arterials and routes that connect towns, every 5 mph over the local limit was linked to a smaller 3% increase in phone handling. These roads often have traffic lights, intersections, roundabouts and stop signs that require drivers to take action periodically, even when traffic is flowing.

An alarming relationship
The increases were larger on roads with higher posted limits. On limited-access roads with 70 mph limits, for example, for every 5 mph a vehicle exceeded the limit there was a 9% larger increase in phone handling than on similar roads with 55 mph limits.

A similar pattern showed up on roads with more access than freeways. Compared with roads posted at 25 or 30 mph, there was a 3% larger increase in phone handling for every 5 mph exceeding the limit on 45 or 50 mph roads and a 7% larger increase on 55 mph roads.

“It’s alarming that the relationship between cellphone manipulation and speeding was the strongest on roads with the highest speed limits,” said Ian Reagan, the IIHS senior research scientist who wrote the study.

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