You would save more lives by harshly punishing drunk or influenced driving; however, most of the lives you save would be that of the drinker or the abuser.

You would save more lives by outlawing motorcycles; however, it would just be the motorcyclists themselves.

Another thing people don't consider is that not all seats in a vehicle are equally safe. The drivers seat is the safest. Front passenger is less safe but still often twice as safe as sitting in the backseat. If you believe picking up your elderly parents and then escorting them in your backseat is safer than them driving alone you might be wrong. This is a fatality mode you easily recognize in the FARS data. Where do most people in a robotaxi sit?

Your biggest clear win would be building better pedestrian infrastructure and improving roadway lighting to reduce pedestrian deaths.