S s' perception of speed and distance, and wind gusts increase steering difficulty. Since this segment lacks confounding variables, speed and lane position can be measured. The suburban segment markedly increases driving demands. S s drive a three-lane expressway at 55 mph, slowing to 45 mph for posted curves. They make frequent lane changes to pass other vehicles and to avoid cross traffic, entering traffic, and stalled cars.
Pedestrians enter and cross in walkways at the signals.
S s monitor the periphery of the visual display and respond to signals which appear at the extreme right and left. The signals are a left arrow, a right arrow, and a horn. S s respond to a left or right arrow with the corresponding turn signal and to the horn sound with the horn button. Measures include response time and number of incorrect responses. The DAT shares the SIM hardware and requires S s to allocate attention to multiple sources of information on three video monitors.