The risk of a pedestrian fatality posed by a collision with a car travelling 30kmh is closer to the risk from a car going 5kmh than that of a car going 50kmh.
Look at the chart here:
http://www.victoriawalks.org.au/safe_speed/
The risk from speed is non-linear.
Risk the pedestrians in speed zone greater than 30kmh, because risk of fatal injury is far lower.
Anyway, the pedestrians don't risk either now. So saying "Folks should be comfortable adding a reasonable risk of death, since it could be far worse!" is not compelling.
But it's a stupid comparison for safety. Colliding with a scooter will rarely be fatal, regardless of the 3x. But cyclist often get killed.
There's a LOT more energy being transferred into whatever the car hits both because it's going much faster and because it's much heavier.
I know its a hard statistic for bikes to swallow. There seems to be no winning for them. But that's my whole point.
Seems fucked up.