An autonomous vehicle includes an under-chassis object detection system for identifying the presence of an object on a road that the autonomous vehicle is travelling upon. The under-chassis object detection system may include a LIDAR system. The object on the road that the autonomous vehicle is travelling upon is of a size that allows the vehicle's chassis to pass over the object on the road. The autonomous vehicle may react to the detected object on the road to operate the autonomous vehicle safely, such as by altering the vehicle's trajectory, by stopping the vehicle, or by communicating with a control center for further instructions.