You reduce the reaction time by paying attention and trying to anticipate things. React to the problem before it happens.
Rarely is a collision the result of some random thing with no warning. Do they test reaction times by flipping on a light with no warning and seeing how long it takes for the subject to hit the brake? Real life isn't like that: New York pedestrians' reaction time to the walk light is -3 seconds.
Because they pay attention to the world around them and anticipate things.
New York's pedestrians move so fast we break the laws of time