The effect of knowledge of closing rate on drivers passing performance was investigated. Three cars and drivers were used: a lead car /lc/, a passing car /pc/, and an oncoming car /oc/. The experiments took place on an unopened section of interstate highway near philadelphia. Drivers were asked to pass when the oc was a given distance or time from the lc. In one experimental condition /full knowledge/ drivers were told the closing rate to be given in each block of trials and were told that closing rate would be constant during that block. They then experienced that closing rate repeatedly. Sufficient trials were given so that their performance was asympotic, or nearly so. Knowledge of results was given after each trial. In a second experimental condition drivers were told verbally what the closing rate would be on the next trial. This condition was the verbal knowledge condition. As a control each driver also received blocks of no knowledge trials in which closing rate varied randomly. The data show that variance in passing behavior is inversely related to knowledge. Comparisons between the performance of drivers receiving closing rate information and those receiving oncoming car speed information are also presented.
Abstract