The 50-driver naturalistic braking study: overview and first results

Considering the importance of vehicle brake systems, it is surprising how little is known about the way that people operate them. Previous ergonomic studies have attempted to define the maximum acceptable resistance to depression in the pedal (Diffrient, Tilley, & Harman, 1993; Eaton & Dittmeier, 1970). Accordingly, they focussed on the responses of weak (5 percentile muscle strength) female drivers and little is known about the full range of braking response. A re-examination of this basic control mechanism is necessitated by the evolution of vehicle systems. The present paper offers an overview of a study measuring driver “pedipulation” in a naturalistic environment. Fifty-eight fully-licensed drivers drove a car for a day. The types of trip analysed included commuting to work, shopping, and picking up children from school. Measures taken included throttle pedal angle, brake pedal pressure, and clutch pedal pressure. The foot well was constantly video recorded during each trip. Main results are presented and comparisons with earlier studies are discussed.