Accident Analysis and Prevention 38 (2006) 1151–1156 Braking hazards of golf cars and low speed vehicles K.J. Seluga, I.U. Ojalvo Technology Associates, 1011 High Ridge Road, Stamford, CT 06905, United States Received 6 February 2006; received in revised form 27 March 2006; accepted 29 April 2006 Abstract Research and analysis of braking issues for golf cars and other low speed vehicles (LSVs) are reported in this study. It is shown that many such vehicles only provide braking for their rear wheels, which can lead to a driver losing control during travel on typical steep downgrades. The braking performance of a golf car equipped with brakes on two or four wheels was analyzed to determine the effects of two and four wheel brake designs on braking efficiency and vehicle yaw stability. Besides reducing braking efficiency, it is demonstrated that installing brakes on only the rear wheels can lead to directional instability (fishtailing) and rollover when the rear wheels are braked until skidding occurs. The nonexistence of golf course standards and the inadequacy of golf car and LSV standards are noted and a connection between this and the comparatively high level of accidents with such vehicles is inferred. Based on these results, it is advisable to install brakes on all four wheels of golf cars and LSVs. In addition, new safety standards should be considered to reduce the occurrence of golf car accidents on steep downhill slopes. © 2006 Elsevier Ltd. All rights reserved. Keywords: Golf car; Low speed vehicle; Braking; Yaw stability; Braking efficiency; Downhill braking; Rollover 1. Introduction 1.1. Problem It is estimated that there were approximately 10,000 golf car related injuries requiring emergency room treatment in the US each year from 2000 to 2004 (CPSC, 2004). Of these accidents, at least 10% involved a car rollover. Statistics also indicate that golf car accidents involving a rollover are roughly twice as likely to lead to injuries requiring a hospital stay as nonrollover acci- dents (CPSC, 2004). Based on the authors’ experiences investigating serious golf car accidents, rollovers often occur as a result of a driver los- ing control of the car while traveling downhill on a car path (Devanney, 2001). One potential source of a downhill loss of control is associated with the current industry practice of build- ing golf cars with brakes on only the rear axle wheels. It has long been understood that a vehicle with skidding rear tires and rolling front tires is directionally unstable (Allen et al., 1991; Collins, 1979; Pacejka, 2006). However, this instability will not always manifest itself in large rotations when the vehicle is driven at low speeds (e.g. 15 mph) on comparatively level ground. This paper E-mail address: kseluga@technology-assoc.com (K.J. Seluga). will show that besides reduced braking effectiveness (when com- pared to four wheel braking), which is especially critical on steep downhill slopes common to many golf courses, rear wheel only brake designs lead to rear tire skidding and reduced yaw sta- bility, creating the potential for a car to easily “fishtail” when the brakes are applied hard. Furthermore, the reduced effective- ness of the brakes on a downhill slope can lead the car driver to falsely perceive a brake failure, causing him to press harder on the brake pedal leading to a locking of the braked wheels and an out of control skid. This hazard will be aggravated at golf courses that incorporate hilly terrain with steep, narrow golf car paths and sharp turns. Such conditions make it desirable to cre- ate golf cars with good braking characteristics for use on courses with downhill slopes of 10 ◦ or more. 1.2. Current braking designs The great majority of the golf cars currently produced by the major manufacturers (e.g. Yamaha, EZ-Go and Club Car) are equipped with brakes on only the rear axle wheels, while low speed vehicles (LSVs) intended for use on public roads are equipped with brakes on either two or four wheels. Both ANSI standard Z130.1-1993, “Golf Cars—Safety and Perfor- mance Requirements,” and Federal Motor Vehicle Safety Stan- dard (FMVSS) #500, “Low Speed Vehicles,” are written such 0001-4575/$ – see front matter © 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.aap.2006.04.023