Studies of driver distraction use a number of measurements as direct or indirect measures. These include tracking eye movements, number of times a driver goes outside of the driving lanes (“lane exceeds”), the time to complete a task (such as turning on the radio, or dialing a cell phone number). Because it is expensive (and potentially dangerous) to run studies while driving, researchers are looking for other means to create valid and reliable measurements, such as using simulations. Ford Research, for example, is completing work on their VIRTTEX simulator.
Because it is difficult to specify absolute measurements of “safe” amounts of driver distractions, researchers also use certain “anchor tasks” as baselines. If a new task–for example, dialing a cell phone–is no more distracting than the anchor task, then there is some confidence that the new task is safe enough. Perhaps ironically, given the original controversy, turning on a radio is often used as an anchor task.
Still, measuring driver workload is a difficult task. “Turning on the radio” using one manufacturer’s radio is markedly different from another’s, for example. Some efforts at standardizing tasks are under weigh.