Rollover Protection for Occupants of Heavy Truck Sleeper Cabs K Friedman*, J Hutchinson*, D Mihora*, S Kumar**, W D Strickland** *Friedman Research Corporation **Safety Research Institute Abstract - It is projected that over 900,000 long-haul sleeper cabs will be on the road by the year 2030. Approximately half of all heavy truck occupant deaths are due to rollovers. This paper considers current occupant sleeper cab rollover protection systems and reveals the results of representative crashes involving vehicles with these cabs. This paper also describes a virtual testing methodology for the evaluation of today’s designs under rollover conditions, along with restraint tests involving both test dummies and humans. Finite element models are also discussed; results of various exemplar restraint configurations are introduced. These data strongly suggest that lateral restraint is critical for the safety of sleeper cab occupants in the event of a rollover accident. INTRODUCTION 6.8 million heavy single-unit trucks and 2.2 million combination trucks were in use in 2007. Reports show that 802 occupants of those trucks were killed and 24,000 were injured. 1 The previous year, nearly 900 occupants of heavy trucks died, 500 of them drivers. More than 4,000 people died in the other vehicles involved in those accidents. 2 In 2006, heavy truck rollover accidents claimed the lives of more than half of the truck drivers involved. 3 There have also been a significant number of fatalities in the other vehicles involved in collisions with heavy trucks. By far, frontal impacts have constituted the majority of vehicle-to- vehicle fatal collisions with heavy trucks. According to data from both the Bureau of Motor Carrier Safety (BMCS) and the Federal Motor Carrier Safety Administration (FMCSA), in the years 2001-2003, 53.4% of accidents in which the occupant of a heavy truck died involved a heavy truck with a sleeper cab. Of these accidents, 11.4% involved the death of a sleeper cab occupant. To be sure, the number of sleeper cabs in the US will increase in the coming years, as the call for faster, more efficient long-distance deliveries grows. It is estimated that 687,000 sleeper cabs were in use in 2005, and that by 2030 that number will have risen to 931,000. 4 FMCSA 393.76, states the following regarding sleeper cab occupant restraint: (h) Occupant restraint. A motor vehicle manufactured on or after July 1, 1971 and equipped with a sleeper berth must be equipped with a means of preventing ejection of the occupant of the sleeper berth during deceleration of the vehicle. The restraint system must be designed, installed and maintained to withstand a minimum total force of 6,000 pounds applied toward the front of the vehicle and parallel to the longitudinal axis of the vehicle. 5 The procedure referenced in the above passage also pertains to SAE J1948 6 , a J standard dealing with sleeper cab occupant restraint. FMCSA 393.76(h), however, fails to address both rollover and side impacts, leaving much to be discussed regarding sleeper cab performance under these conditions. Numerous other production systems have made the same omission. Reed 7 filed a patent in 1990 for a restraint for a rear-seat passenger as seen in Figure 1. Her designs involve webbing looped around a person’s waist in various ways and anchored to the