Applications such as static warning signs, truck speed limits, and educational videos
at state weigh stations have all been used to minimize this condition. The Dynamic Downhill Truck Speed Warning System (DDTSWS), developed in 1995, provides specific information to individual truckers before they enter the steep grade sections. The first DDTSWS was placed west of the Eisenhower Tunnel in the westbound lanes of I-70. DDTSWS uses inductive loops, WIM technology, and a VMS. First, the trafAc loop detectors trigger the system. Then, WIM determines the truck weight, speed, and axle configuration. Finally, an algorithm within the computer system computes a safe speed based on this information and alerts the driver through a VMS. Since its deployment, truck-related accidents have declined on these 6-percent and 7-percent grade sections
even while the volume of truck trafAc has increased by an average of 5 percent annually. Currently, British Columbia, Oregon, and West Virginia are designing and constructing similar systems.