New research from Professor David Strayer says that our minds wander for nearly half a minute after a hands-free call or text.
Even if you wait until you’re at a stoplight to make a hands-free phone call, you’re not as safe as you think. A recent study sponsored by the AAA Foundation for Traffic Safety shows distractions from in-vehicle messaging persist long after the message ends. Here’s what the study found.
Mental recovery takes time
Test subjects needed up to 27 seconds to fully refocus on driving after ending a hands-free call or sending a text message using a voice-controlled system. These lingering distractions, known as residual costs, were determined by measuring participants’ reaction times to potential hazards as they drove on suburban roads. “At 25 mph, a vehicle would travel up to 988 feet [almost the length of three football fields] before the residual costs completely dissipate,” says David Strayer, the University of Utah professor who led the study.
Hands free isn’t risk free
In prior research, Strayer’s team established a five-point scale to assess distraction levels from in-car tasks, ranging from listening to the radio (category 1) to working on a set of math-memory problems (category 5). AAA considers distractions at category 2 or higher to be unsafe—and none of the voice-controlled systems available in 10 vehicles or on three smartphones fell below this threshold. Among vehicle-based options, distraction ratings ranged from a low of 2.4 to a high of 4.6. Smartphone systems spanned a range of 3.0 to 3.8 for calls, and hands-free text messages rated even worse.
Familiarity doesn’t help
More disturbingly, the study revealed that participants showed only marginal improvement in performance even after a week of practice on voice-guided systems, leading researchers to conclude that such distractions cannot be practiced away.
This article was first published in Spring 2016. Some facts my have aged gracelessly. Please call ahead to verify information.
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