CDL General Knowledge TestDriving SafelyMedium
You are driving a commercial vehicle and must make a lane change to the right. After checking your mirrors, you see a car in the right lane slightly behind your rear tandem axles. What should you do?
- ASpeed up slightly to get ahead of the car before changing lanes.
- BWait until the car passes or drops back sufficiently to be seen in your convex mirrors or no longer in your blind spot.
- CWait until the car is visible in your side mirror and then signal and change lanes.
- DSignal and immediately change lanes, as they are not directly beside you.
Show answer & explanationAnswer & explanation
Correct answer: B. Wait until the car passes or drops back sufficiently to be seen in your convex mirrors or no longer in your blind spot.
The area beside and slightly behind a large commercial vehicle, particularly near the rear tandem axles, is a common blind spot. You must ensure the area is clear by waiting for the vehicle to pass or drop back enough to be visible in your mirrors or no longer in the blind spot before initiating a lane change.
Why the other options are wrong
- A. Speeding up aggressively to cut off another vehicle is unsafe and illegal.
- C. If the car is only visible in your side mirror, it's still likely in your blind spot for a safe lane change.
- D. Changing lanes immediately with a vehicle in your blind spot is extremely dangerous and could cause a collision.
Commercial Vehicle Blind Spots
Large commercial vehicles have significant blind spots, often called 'No-Zones,' where smaller vehicles disappear from a driver's view. These areas are directly in front, behind, and on either side of the truck.
- Front blind spot: up to 20 feet.
- Rear blind spot: up to 200 feet.
- Side blind spots: extend from the cab to beyond the rear of the trailer, especially on the right side.
- Always check mirrors and use turn signals well in advance.
Memory trick: No-Zones are real, check all you can feel, before you steer!