Driving Safely
Driving Safely is the broadest domain on the Kentucky CDL General Knowledge exam. It tests whether you can control a commercial vehicle defensively, scan for risk, manage speed and space, and respond to emergencies without losing control.
Core rules
- Wear the seat belt whenever the vehicle is moving; it keeps you behind the wheel in a crash.
- Scan 12 to 15 seconds ahead in cities and farther on open highway. Look for brake lights, merge traffic, work zones, and pedestrians.
- Use the following-distance rule based on vehicle length and speed. Below 40 mph, allow one second for each 10 feet of vehicle length; above 40 mph, add one second.
- Slow before curves, railroad crossings, and wet or icy pavement. Brake smoothly and avoid sudden steering.
- If a tire fails, hold the wheel, ease off the accelerator, and avoid hard braking until speed drops.
Worked example
A 60-foot combination travels at 55 mph. The base gap is 6 seconds (60 feet divided by 10). Because speed is above 40 mph, add 1 second, so the minimum following distance is 7 seconds. If a fixed roadside object passes the rear of your vehicle and you reach it only 5 seconds later, you are 2 seconds too close. Reasoning: the rule converts length and speed into a time gap you can check while driving.
Traps
Counting car lengths instead of seconds; following a large vehicle so closely that you cannot see the road ahead; and braking hard in a curve, which can cause a rollover or jackknife.