Abstract: A warning and safety system for tractor-trailer dump trucks to indicate that the raised trailer is in a precarious position and in danger of tipping over, which system measures the pivot angle or the angle of revolution of the front end of the trailer. When the raised trailer is in an unstable position and begins to tip over, the front end of the trailer pivots on the hydraulic telescoping cylinder extending from the fifth wheel of the trailer. Mounted directly onto to hydraulic telescoping cylinder is an instrument sensitive to angular motion, or, alternatively, mounted on the fifth wheel of the tractor is a pivoting canister containing that instrument, from which a cable extends, parallel to the hydraulic telescoping cylinder, to the bottom of the front end of the trailer, where the cable engages with a pulley arrangement securely mounted on the cylinder well of the trailer.