Reaction time is defined as:

• A. The time to react to a hazard after noticing it
• B. The time to steer the vehicle out of a skid
• C. The time to accelerate to reach speed
• D. The time to apply the brakes after starting

Answer: (A)

Reaction time is the interval between noticing a hazard and starting to respond. When you see something risky on the road, your brain processes the signal, decides what action to take, and you initiate that action. The time it takes to actually complete the physical action (steering, braking, etc.) after you begin is movement time, which is counted separately from reaction time. So the definition described matches the moment you notice a hazard and begin to respond. Options describing steering out of a skid, accelerating to speed, or braking after starting refer to specific actions or subsequent steps, not the initial noticing-to-response interval.