The speed range from 20mph to 35mph (give or take) has been pretty well researched and documented as a range where pedestrian fatalities ramps up dramatically.

The speed range from 20mph to 35mph (give or take) has been pretty well researched and documented as a range where pedestrian fatalities ramps up dramatically. Additionally, stopping distance (very rough average) will double for most drivers from 20mph to 35mph. So, yeah, for this range of speeds, that 10-15mph difference is absolutely critical to maintain pedestrian safety. Remember, 20mph is slower than the default residential speed of 25mph (in the US). It's almost exclusively used in tight neighborhood streets, where pedestrians (children in particular) should be expected. 70mph vs 80mph, I don't so much care about. In theory, those speeds are only ever seen on a limited-access highway. The California bill is stupid, but probably DOA as well. But, that doesn't mean the problem it's trying to solve doesn't exist.