CDL Combination Vehicles TestDriving Combination Vehicles SafelyMedium
You are driving a combination vehicle on a four-lane highway and need to change lanes to the left. Which of the following is the most significant blind spot you must check before initiating the lane change?
- AThe area in your rearview mirror showing traffic several car lengths back.
- BThe area alongside your trailer, especially the left side.
- CThe area directly behind your trailer.
- DImmediately in front of your truck.
Show answer & explanationAnswer & explanation
Correct answer: B. The area alongside your trailer, especially the left side.
Combination vehicles have large blind spots, particularly along the sides of the trailer. When changing lanes to the left, the entire length of the left side of the trailer and the area just behind the tractor's left door are critical blind spots where other vehicles can be hidden.
Why the other options are wrong
- A. This area is covered by mirrors and not considered a blind spot; it shows traffic you can already see.
- C. The area directly behind the trailer is a blind spot for backing, but less critical for a forward left lane change unless you're concerned about someone tailgating too closely to be seen in side mirrors.
- D. While it's important to know what's in front, this is not typically a 'blind spot' in the traditional sense for a lane change.
Combination Vehicle Blind Spots
Areas around a large vehicle that cannot be seen by the driver using mirrors, requiring extra vigilance and checks.
- Large areas directly in front of the cab.
- Along both sides of the trailer, especially near the rear.
- Directly behind the trailer.
- Drivers must constantly check mirrors and 'get out and look' when unsure.
Memory trick: Sides are wide, where dangers hide.