But what about an even lower speed? If 15 mph is good, then 5 mph is better. And if 5 mph is better, 1 mph is superior once more.
I think we can agree there is a point where slow becomes too slow and the 'sufficient planning' becomes an unreasonable burden. So given we aren't operating off the notion that slower is inherently better, then there is some equation giving us our optimal point. What if that point is 45 mph instead of 15 mph?
In short, how do we argue that 15 mph is better than 45 mph that can't also be applied to speeds lower than 15 mph?
It's easy - you have diminishing improvements in pedestrian survival rates. 40MPH+ is associated with a fatality rate of over 50%, whereas you get to 30MPH and you have 7%, and 20MPH is essentially zero: https://nacto.org/docs/usdg/relationship_between_speed_risk_...
Even if it is close to zero, how do we decide if the lives saved from going from a .1% fatality rate to a .09% fatality rate is worth the speed reduction or not?
But what about an even lower speed? If 15 mph is good, then 5 mph is better. And if 5 mph is better, 1 mph is superior once more.
I think we can agree there is a point where slow becomes too slow and the 'sufficient planning' becomes an unreasonable burden. So given we aren't operating off the notion that slower is inherently better, then there is some equation giving us our optimal point. What if that point is 45 mph instead of 15 mph?
In short, how do we argue that 15 mph is better than 45 mph that can't also be applied to speeds lower than 15 mph?