Protection of Drivers and Spectators from Pit Entrance Injuries Incurred During Loss of Control Accidents 942468
At Indianapolis Motor Speedway (IMS), as well as at a large number of other tracks and temporary racing circuits, the pit lane is separated from the racing surface itself by a wall. The wall is intended to reduce the dangers to pit crew members, spectators and racers themselves, and to prevent interaction between racing and pitted cars.
We examine the effectiveness of an attenuation device placed at the head end of the pit wall at IMS. Calculations are presented which show that the device can reduce the potential for injury to drivers by absorbing kinetic energy, by distributing the impact load over a large car area and by reducing and smoothing the acceleration pulse presented to the driver. Because driver restraint systems are not designed for high-g lateral loading, this attenuation represents a real safety feature in the case of a sliding situation. The device itself was (inadvertently) tested by a NASCAR vehicle during a practice session at IMS. Through a video analysis and data acquired from timing devices imbedded in the track surface, the accident was reconstructed and the wall attenuation device performance was compared to expected results. A simple calculation addresses the potential for ablative or nonablative padding of the entire wall surface of a complete race-track such as IMS. Energies involved, nominal material sizes needed, and a discussion of the qualitative effects of a wall contact are presented. Two types of wall contact can be considered, (a) a brush-by or wall sideswipe accident, in which the vehicle velocity vector is nearly parallel to the wall surface, and (b) an impact where the velocity vector is at a significant angle with respect to the wall (but still at an acute angle). The impossibility of a “head-on” collision at IMS, or at nearly every other racing venue, is shown. Worst-case scenarios were evaluated at IMS.
Spectator and pit crew safety were addressed. The potential for launching a car upward and out over the actual racing surface, or into the pits, or even into the spectator stands is discussed and shown to be very small. The attenuator device was specially designed and constructed to minimize this possibility, and the construction techniques used are presented. Although the single accident which occurred was a (relatively) low-speed accident, results were promising in view of what was expected.
Finally, a series of 1/8 scale radio-controlled model vehicle experiments were conducted against prototypical wall padding materials for estimation of potential for bounceback of vehicles into the racing stream. Photographs and video of the contacts are available, and a cataloging of results is presented.
The results reported here on attenuation devices are applicable to all racing locations where pit walls are employed, and the final section of the paper has relevance for all tracks where car-to-wall contacts are possible and/or likely.