Previous work (Perron et al., 2001) on emergency brake application concluded that driver population diversity and “the overlap of braking parameter distributions between normal conditions and emergency situations” is such, that triggering criteria cannot both detect all emergency braking actions and never activate the assistance in situations where it is not necessary. The objective of this study was to investigate driver-braking characteristics, in order that future systems might achieve greater effectiveness.

48 drivers drove an instrumented vehicle on a public road section before arriving at a test track, where they were instructed to follow at their preferred distance another vehicle towing a trailer. They were told the aim was to measure their preferred car-following distance. They were naïve to the fact that 0.2 miles down the track the trailer would be released and rapidly decelerate to a stop. The main variables analysed included “throttle-off” rate, brake pedal pressure/force, and clutch pedal pressure/operation.

The results indicate a series of relationships exploitable by an intelligent brake assist system. An intelligent brake assist system could take advantage of those characteristics and adapt its performance to individuals’ braking style.

Limitations of the study include resource constraints (use of a single instrumented vehicle, time-limited access to the test track)and the contrived nature of the emergency braking scenario (need for surprise element, practically a one-off study, limitation of speed to 30mph/48kmph). The study provides evidence of a background for a customisable brake assist system that learns from the driver and adjusts its full-brake trigger accordingly.