An experiment was conducted to assess the distraction potential of secondary tasks performed using in-vehicle systems (radio tuning, destination entry) and portable phones (10-digit dialing, selecting contacts, text messaging) while driving.
One hundred participants, ages 25-64, completed a single session in which they drove a low-fidelity (PC-based) simulator while performing the secondary tasks. The phone tasks were performed with two smart phones, one with a touch screen interface (iPhone) and one with a hard button interface (Blackberry). The Dynamic Following and Detection (DFD) driving protocol, which combines car-following with target detection, in which drivers responded to simple visual targets presented in the simulated roadway display, was used. Each combination of primary (driving) and secondary task was performed during a single 3-minute drive. Driving performance metrics included: lane position variability, car-following delay, target-detection accuracy and target detection
response time.
http://www.nhtsa.gov/DOT/NHTSA/NVS/Crash%20Avoidance/Technical%20Publications/2011/811510.pdf
