The accelerometer exactly matches wheel rotation rate when you are driving in a straight line on a planar surface[1] in a vehicle with no toe. This is rarely th

The accelerometer exactly matches wheel rotation rate when you are driving in a straight line on a planar surface[1] in a vehicle with no toe. This is rarely the case: roads aren't perfectly flat, and outside of North America, aren't even remotely straight in most circumstances, and the handling characteristics of 0 toe are terrible. Granted, the inaccuracy from non-planarity of the road is minimal, but building an accurate enough model of tire slip from steering geometry is hard, and changes based on the level of wear on the tires, their temperature, and the road conditions, and the deviation between acceleration and wheel telemetry adds up very quickly. So yes, you absolutely do need an IMU for self-driving.