Bicycling tasks relation to stability measures during alcohol intoxication

Abstract

Bicycling accidents are a major traffic safety problem and are deemed ‘an unacceptable human and social price for EU citizens’. One of the major causes for bicycling accidents is loss of balance. A related influencing factor is alcohol intoxication. It is a primary, long term, safety objective to develop safety systems for the cyclist. The present work aimed to understand how to measure cyclists’ instability via steering and leaning inputs, while considering that steering and leaning might vary depending on the cycling task being performed. Of 28 participants, 19 were given doses of alcohol up to 1.0‰ and 9 remained sober (control group). Breath alcohol concentration was measured. The participants repeated the cycling test track session five times (with each block lasting 35 minutes). The track session contained three different tasks: cycling slalom, straight, and slowly. Speed, yaw rate, and roll rate were assessed continuously. Yaw rate and roll rate were relatively sensitive for the different cycling tasks. The threshold level of the angular velocity measurements was related to the cycling task performed. Alcohol intoxication at 0.7‰ had a significant impact on performance. The rather simple measurements used can detect instability. Instability should be measured differently depending on the cycling task performed. The study represents a small step towards a safety system for cyclists.