Currently, among other intelligent transportation system applications, there is an increased interest in using an "in-vehicle warning system" to mitigate truck-rollover crashes on interchange ramps. Because the cost of installing the system in an entire truck fleet would be significant, a basic question is how large a safety problem is addressed. This study was an attempt to estimate the annual national frequency and cost of large-truck accidents on interchange ramps that result in rollovers. Using tabular analysis of a five-state database, the estimate was that approximately 11 percent of total truck involvements are on interchange ramps and that between 44 and 52 percent of the incidents result in rollovers. Both urban and rural locations present significant problems that could be addressed by an in-vehicle warning system. Combining this information with General Estimates System figures for total national truck crashes, it is estimated that there are between 4,400 and 5,000 truck rollovers on ramps each year nationwide. The annual economic cost of these rollovers is between 405 million and460 million. These data provide both information to safety engineers on the size of a significant truck safety problem and a base for a meaningful cost-benefit analysis of installing the in-vehicle warning system. Although available data do not allow a detailed cost-benefit analysis, a simplified analysis of "breakeven costs" indicates that such a device is highly dependent on the level of effectiveness, ranging from approximately 300 per truck to3,200 per truck.

Wang, J. and F.M. Council. Estimating Truck-Rollover Crashes on Ramps by Using a Multistate Database. In Transportation Research Record: Journal of the Transportation Research Board, No. 1686, Transportation Research Board, National Research Council, Washington, D.C., 1999, pp. 29-35.