Re:Waymo robotaxi hits a child near an elementary school in ...
by mlyle on Friday January 30, 2026 @12:24AM
(#46820832)
I think the strategy is a lot more nuanced than that.
In any case, with zero reaction time, linear deceleration time to stop is proportional to velocity squared. With reaction time, the linear deceleration time is that plus the velocity times the reaction time.
so the two cases we're comparing are 17 * r + (17^2 - 5^2) vs. 16 * r + (16^2), or 17 * r + 264 vs 16 * r + 256. As long as reaction time isn't negative, a vehicle that could slow to 5MPH starting at 17MPH could slow to 0MPH starting at 16MPH.
(There are weird things that happen at <2.5MPH reducing deceleration to sublinear, but the car moves only a few inches at these speeds during a panic stop).
In any case, with zero reaction time, linear deceleration time to stop is proportional to velocity squared. With reaction time, the linear deceleration time is that plus the velocity times the reaction time.
so the two cases we're comparing are 17 * r + (17^2 - 5^2) vs. 16 * r + (16^2), or 17 * r + 264 vs 16 * r + 256. As long as reaction time isn't negative, a vehicle that could slow to 5MPH starting at 17MPH could slow to 0MPH starting at 16MPH.
(There are weird things that happen at <2.5MPH reducing deceleration to sublinear, but the car moves only a few inches at these speeds during a panic stop).