Comparison of Driver Braking Responses in a High-Fidelity Simulator and on a Test Track

The braking responses of drivers in the Iowa Driving Simulator (IDS) were compared with those of drivers on a test track. The braking profile of drivers was compared in last-minute braking situations in which drivers were instructed to brake "normally" or "hard." Although the motion and visual cues in the IDS are imperfect, the data agree in many respects. The general pattern of results is similar, with the initial speed and lead vehicle deceleration affecting drivers on the test track and in the simulator in a similar way. In several experimental conditions, the similarity of the responses went beyond the general pattern of response. The mean values were almost identical in several instances, and the values were frequently well within the confidence intervals. Although the simulator and test track drivers performed similarly, differences are apparent from the onset of braking, through the braking process, and in the outcome of the braking event. The instructions concerning normal and hard braking had little influence on the behavior of drivers in the simulator. Contributors to these differences include the limited visual and vestibular cues in the simulator and the extended practice on the test track.