Driving Safely
The Driving Safely domain tests the judgment behind every mile: speed choice, visual search, following distance, and response to hazards. Michigan CDL questions often put you in a scenario and ask what a professional driver should do, so learn the rule and the reason behind it.
Speed and space
- Drive at a speed that lets you stop within the distance you can see ahead. The posted limit is a maximum for good conditions, not a target.
- Use the CDL following-distance rule: one second for each 10 feet of vehicle length below 40 mph, plus one extra second above 40 mph.
- At night, in rain, fog, or snow, slow down and increase space; never overdrive your headlights.
Seeing and responding
Search 12–15 seconds ahead, check mirrors every 5–8 seconds, and scan intersections. At a railroad crossing, slow down, look both ways, and never stop on the tracks. If a skid starts, stop braking, turn in the direction you want the front of the vehicle to go, and avoid oversteering.
Worked example
You drive a 60-foot combination at 55 mph. Base following time = 60 ÷ 10 = 6 seconds. Because you are above 40 mph, add 1 second, for 7 seconds. At 55 mph you travel about 81 feet per second, so 7 seconds is roughly 565 feet-more than a football field. A four-second gap that feels normal in a car is too close in this vehicle.
Traps
Counting vehicle lengths instead of seconds; forgetting the extra second above 40 mph; treating the posted limit as safe in rain; and watching only the vehicle ahead instead of the whole scene.