A Test of the Tau-Dot Hypothesis of Braking Control in the Real World

This paper describes a controlled experiment that employed instrumented vehicles in a real-world driving task to compare D. N. Lee's (1976) tau-dot hypothesis of braking control with an alternative based on the direct estimation and control of ideal deceleration (T. Yates et al., 2004). Drivers braked to stop as closely as possible to a visual target from different starting speeds and times-to-contact. The data provided little support for the tau-dot hypothesis, and analysis suggests that braking in the real world is better explained by a direct deceleration strategy.