Abstract: A system for preventing the overturning of the bin of a tipper truck during the raising of the bin for purposes of unloading includes a lateral level sensor to sense the lateral orientation of the tipper truck, and a longitudinal level sensor for sensing the longitudinal inclination of the bin. A processor processes the outputs of the lateral and longitudinal level sensors to derive a measure of risk of overturning. The system also includes a display for displaying an indication responsive to the measure of risk. The processor preferably processes the output of the lateral level sensor to calculate a rate of change of lateral inclination of the tipper truck. Optionally, a mechanism may be provided for interrupting the raising of the bin, the mechanism being responsive to the processor.