A vehicular sensing system includes a plurality of multiple input multiple output (MIMO) radar sensor units disposed at a vehicle so as to have respective fields of sensing exterior of the vehicle. Each MIMO radar sensor unit includes a plurality of transmitting antennas and a plurality of receiving antennas, with each transmitting antenna transmitting radar signals and each receiving antenna receiving radar signals. Outputs of the individual MIMO radar sensor units of the plurality of MIMO radar sensor units are provided to an electronic control unit (ECU) using a communication protocol of the vehicle and, responsive to the outputs of the MIMO radar sensor units, the ECU detects objects present exterior the vehicle. The vehicular sensing system adjusts the total number of transmitting and receiving antennas utilized by the plurality of MIMO radar sensor units in accordance with complexity of a surrounding environment of the vehicle.