The vast majority of pedestrians survive getting hit by a car, not all incidents happen at highway speeds. A difference between a mass of 1 and 3 tons would absolutely make a difference in lethality.
https://www.cdc.gov/transportationsafety/pedestrian_safety/i...
Weight is directly called out as a factor:
> SUVs can cause more harm to a person on foot when a crash occurs because of their greater body weight and larger profile