1993 Buick Roadmaster Owner's Manual - Page 166

Braking Braking action- involves perceDtion time and reaction 'time. * - First, you have to decide to push on the brake pedal. That's perception time. Then -you have to bring up your foot and do it. That's reaction-time. Average reaction time is about 314 'of a second. But that's only -an average. It might be less with one driver and aslong as twoor.threeseconds or .more with another.