A sensing system for a vehicle includes at least one radar sensor disposed at the vehicle and having a field of sensing exterior of the vehicle. The at least one radar sensor includes multiple transmitting antennas and multiple receiving antennas. The transmitting antennas transmit signals and the receiving antennas receive the signals reflected off objects. Radar data sensed by the at least one radar sensor is received at a control, and a vehicle motion estimation is received at the control. The control, responsive at least in part to the received sensed radar data and the received vehicle motion estimation, generates a surface model representative of the surface along which the vehicle is traveling.