Cargo tank roll stability study: final report

Abstract

Rollovers are among the most serious crashes of cargo tank motor vehicles carrying hazardous materials. They are more likely to be fatal to the driver of the vehicle than other crashes, and they can cause spills and necessitate highway closures. The Federal Motor Carrier Safety Administration (FMCSA) has identified the need to study cargo tanks, from design through operation, to improve their roll stability. The objective of this program was to evaluate four complementary approaches to reducing the incidence of cargo tank truck rollovers: improving the training of drivers, deploying electronic stability aids, implementing new vehicle designs, and learning lessons from highway designs. The benefits, in terms of reduced numbers of rollover crashes, that could accrue from each approach, have been estimated, along with the costs of achieving those benefits. All four approaches are expected to be cost beneficial. Ultimate responsibility for the safety of the vehicle rests with the driver. The driver must be aware of the situations that can lead to rollover and have the skills and vigilance to prevent those situations from developing. Drowsiness and inattention together contribute to 1 in 5 cargo tank rollovers, so adherence to viable and legal schedules of work and rest is essential. Modern, motion-base simulators can help new drivers acquire skills more quickly and without consuming fuel, so simulators can pay for themselves through reduced training costs alone, for those carriers large enough to afford them. Electronic stability aids automatically slow a vehicle when it starts to round a corner too fast. Excessive cornering speed accounts for about 1 in 5 cargo tank rollovers, and these devices can be quite effective in what they do while adding only marginally to the cost of a tractor or trailer. Vehicles with more stable designs are available on the market today. Lowering the trailer’s center of gravity by only three inches can reduce rollover incidence by more than 10 percent. However, these trailers have been slow to gain market share because they have a cost premium and their benefit is not widely appreciated. Improvements in highway geometry, surface, or signage, of course, have to be considered at individual sites.Federal Motor Carrier Safety Administration, Washington, D.C.http://deepblue.lib.umich.edu/bitstream/2027.42/64890/1/102503.pd