Feasibility of an Automatic Truck Warning System

DTFH61-91-R-00069
One of the identified truck accident types that occur on curved exit ramps at interchanges is truck rollover. A truck will overturn or rollover if the lateral acceleration imposed upon it as it travels around a curve of a certain radius and superelevation is greater than allowable given its loading condition. Also, there is a speed at which rollover will occur. This report deals with an automatic warning system to prevent truck rollover. Within the study, three different options were identified and evaluated for feasibility. Of the three, the option selected for further definition and cost-effectiveness analyses was an inroad detection/warning system. The system consists of two detection stations upstream of the curve with the combined ability to detect a truck speed, weight, and height threshold. The warning system is a combination of a static warning sign and a fiber-optic warning message sign, which would be activated if the controller determined that the truck would be operating at the rollover threshold speed or faster by the time it reached the point of curvature. This report provides the details of the design, its costs, and its cost-effectiveness. Also, design plans and specifications were prepared for three installations on the Capital Beltway in Maryland and Virginia.