Although all types of vehicles are subject to skidding, particularly in adverse weather conditions, powered two-wheeled vehicles have the highest incidence of accidents in which it is a factor. The inherent instability of these vehicles makes capsize almost certain if a wheel is locked during braking, leading to risk or injury to the rider. There is a growing body of evidence, both from accident studies and observation of the behaviour of motorcyclists, that riders do not brake in a safe and effective manner. In particular, the front brake is used insufficiently or not at all;​ this is said by many riders to be because of their fear of the consequences of locking the wheel.

Research into the application of anti-lock brake systems for motorcycles has been conducted by TRRL during the last twenty years. This has demonstrated the possibility of reducing the incidence of skidding and improving braking performance generally by the widespread use of such systems. Research has reached the stage where reliable anti-lock systems are available but little is known about the way in which riders would use them and how they would react to their presence on a motorcycle, TRRL and Lucas Girling Limited have therefore undertaken a joint project to acquire data from a field trial of seven motorcycles equipped with an anti-lock system developed by Lucas Girline. The machines are in use with a number of Police forces and commercial organisations and are expected to cover relatively high mileages during the three year duration of the trial. This paper represents some of the information obtained at the half-way stage of the trial and gives details of reliability and riders' reaction and comments.