Commercial drivers are involved in collisions less frequently, and the more stringent licensing requirements (i.e. a law) are probably helping with that.

Drivers knowing that they will get away with mowing down a pedestrian so long as they say they didn't see them is also going to encourage dangerous driving.

Most importantly, laws that promote safer street designs make a massive difference in pedestrian fatalities.

All this to say that: laws do protect people from 2ton hunks of steel.