Distracted driving is a factor in approximately 3,000 crashrelated fatalities in the United States each year. Studies have shown that the risk of a crash is four to six times greater while using a cell phone, with even higher rates for texting. Despite public warnings and laws, smartphone tasks that require devoted attention, such as texting, emailing, or web browsing, remain common while driving. Most states restrict hands-held cell phone use, including talking and texting, but none have addressed handsfree use, which can also be extremely distracting. Additionally, there is growing evidence that the effects associated with phone use linger beyond the initial loss of attention, known as a “hangover” effect, and are associated with hazardous driving behavior. Researchers at the Schools of Medicine and Engineering at UC San Diego recently concluded an experimental study on driving safety in which 97 participants were asked to perform simulated driving tasks while receiving a handsfree call or short text message. Researchers measured each participant’s driving reactions (i.e., change in speed, amount of swerving, and drifting outside one’s lane), whether they responded to visual cues at the edges of the screen (simulating rear view mirrors), and how much of the road ahead drivers focused on after being distracted.

Drivers know that smartphones distract. Trying to limit distraction, drivers can use handsfree devices, where they onlybriefly glance at the smartphone. However, the cognitive cost of switching tasks from driving to communicating back todriving adds an underappreciated, potentially long period to the total distraction time. This project measured the effectsof handsfree smartphones on driving behaviors by engaging ninety-seven 21- to 78-year-old individuals whoselfidentified as active drivers and smartphone users in a simulated driving scenario that included smartphonedistractions. Peripheral-cue and car-following tasks were used to assess driving behavior, along with synchronized eyetracking. This research found that simulated driving performance drops to dangerous levels after smartphone distractionfor all ages and for both voice and texting. The participants swerved for 15.1 seconds after a voice distraction and for alonger 20.6 seconds after a text distraction. Participants from the 71+ age group missed seeing about 50% of peripheralcues within 4 seconds of the distraction. Coherence with the lead car during following task dropped from 0.54 to 0.045during distraction, and seven participants rear-ended the lead car.