Illinois Driving Permit Practice Test 2025 - Free Driving Permit Practice Questions and Study Guide

Maintaining a following distance of three seconds behind the vehicle ahead is considered the proper guideline under normal driving conditions. This duration allows for sufficient time to react in case the vehicle in front suddenly stops or slows down.

The three-second rule is based on the time it takes for a driver to perceive a hazard and begin braking. This distance provides an adequate buffer, reducing the risk of a rear-end collision, especially in varied situations like sudden braking or unexpected obstacles. Drivers can estimate this distance by choosing a fixed point along the roadside, such as a sign or tree, and counting the seconds it takes until their own vehicle passes that point after the vehicle in front does.

Shorter following distances, such as one second, are too close and can lead to dangerous situations because they significantly reduce reaction time. Distances longer than three seconds, while they may feel safer, are typically unnecessary under normal conditions and can contribute to traffic slowdowns as they create larger gaps that other drivers might fill in.