Offered for presentation at the Annual Meeting of the Highway Research Board January, 1965. To simulate the moment when a driver is faced with an impending hazard, a device has been constructed which (1) shows pictures of a traffic situation with an imminent hazard (2) which the driver must perceive and interpret (3) while under the stress of time pressure and (4) while carrying on an distracting motor response. The picture is covered by a tray of blocks which are removed by SF as to bring the stimulus picture into view, ii.e., accreted a stimulus. Block removal is paced by audible clicks of a matonome. Three scores are recorded: stimulus size accreted by S (number of blocks removed), number of errors of interpretation of hazard, and discrepancy between time used and time allotted by the metronome. This technique was first tested with a small (N=16) ad hoc sample, with the result that those subjects who accreted a relatively smaller stimulus (i.e., removed fewer blocks) and had relatively more errors of interpretation of the pictured hazard had markedly higher accident rates. This finding is conformed with a second sample of 103 Peace Corps Volunteers. In training for service overseas. Pertinent data from this sample are presented in Table 8 below. Subjects are divided into four categories on the blocks (b) and Errors (E) scores (the two which correlate best with accident rates). The category of Ss scoring above the mean on Blocks and Errors is coded Hi Hi, etc.
Abstract