when driving, the average reaction time is __________.
As an integral part of the stopping sight distance, a value for the brake reaction time must be assumed. Extensive research has shown that 90% of the driving population can react in 2.5 seconds or less. The brake reaction time normally used in design, therefore, is 2.5 seconds. The distance traveled during the brake reaction time can be calculated by multiplying the vehicle's initial speed by the brake reaction time.