Safe Driving Practices and Defensive Driving
Core concepts
Defensive driving means assuming other drivers may err and building margins for their mistakes. Central skills: scanning far ahead, checking mirrors regularly, maintaining following distance, and managing space to the sides and rear. Understand the effects of alcohol, fatigue, and distraction on reaction time, and know that Illinois law sets a 0.08% blood-alcohol limit for adult drivers with a zero-tolerance standard for drivers under 21. Recognize that visibility and traction change with weather, so speed and following distance must drop in rain, snow, and fog. Use headlights in fog and low beams in rain; high beams in fog reflect back and reduce visibility.
Traps to watch
Questions often frame a scenario where you must choose between "maintain speed" and "slow down and increase space." When conditions degrade, the correct answer is almost always to reduce speed and increase following distance. Another trap: hydroplaning is best handled by easing off the accelerator and avoiding hard braking or sharp steering. Watch for questions about right-of-way at intersections where a driver is already in the intersection - you should not assume you may proceed just because your light is green.
Worked example / rule of thumb
At highway speed, use the three-second rule in good conditions; in rain, double it to six seconds, and in snow or ice, extend further. Rule of thumb: if the vehicle ahead passes a fixed object before you can count three seconds, you are too close. If someone tailgates, increase the space ahead of you so you can brake gradually rather than abruptly.