A collision avoidance system includes a plurality of cameras disposed at a vehicle, and an electronic control unit that includes an image processor operable to process image data captured by the cameras. A plurality of other sensors sense at least one of rearward and sideward of the equipped vehicle and capture sensor data. The collision avoidance system may determine imminence of collision with the equipped vehicle by another vehicle present exterior the equipped vehicle responsive at least in part to (a) image processing by the image processor of image data captured by a forward-viewing camera, a rearward-viewing camera, a driver side-viewing camera and/or a passenger side-viewing camera, and (b) radar data sensed by the plurality of other sensors, lidar data sensed by at least one lidar sensor of said plurality of other sensors and/or information transmitted to or from the equipped vehicle via a car2car (v2v) communication system.