During the design process, it’s common to conduct Stopping Sight Distances (SSD) checks. 
SSD is the distance to enable a normally alert driver, travelling at the design speed on wet pavement, to perceive, react and brake to a stop before reaching a hazard on the road ahead. This calculation involves assuming a Reaction Time. However, nearly half of all crashes (45%) involve drivers who didn’t even have time to hit the brakes. 
It is important to acknowledge that textbook braking scenarios are based on assumptions (including that there are no dynamic visual obstructions).

Source of the data: Fitzharris et al., Enhanced Crash Investigation Study (ECIS) Report 3: Understanding Contributing Factors for Serious Injury Crashes Using Crash Chain Analysis, Dec 2022.