The **reaction time** is the interval that elapses from when a driver perceives an obstacle until they make the decision to brake. Under normal conditions, this time is usually **0.75 seconds to 1 second**. This means that, on average, a driver takes approximately **1 second** to react to an unforeseen event.

This time can vary depending on several factors, such as the physical and psychological state of the driver. For example, fatigue, alcohol or drug consumption, and lack of attention can increase the reaction time. However, under optimal conditions, the reaction time remains around **1 second**.