Researchers mounted cameras inside a car to track eye and head movements. The participants were fitted with electroencephalographic (EEG) caps to chart brain activity, helping researchers determine the “mental workload.” Response time to traffic lights was recorded using a “Detection-Response-Task” device.
Listening to the radio presented a minimal risk. Talking on a cellphone, whether handheld or hands free, presented a moderate risk. However, listening and responding to a voice-activated email program created an “extensive” risk.
Bottom line: When behind a wheel, you only true focus should be the road and your driving.