Colorado CDL Practice Test

When should you check your mirrors before changing lanes?

1. Immediately after you start the lane change

2. Before changing lanes to ensure there is enough space

3. Only after completing the lane change

4. Only when you are merging onto a highway

The correct answer is: Before changing lanes to ensure there is enough space

Checking your mirrors before changing lanes is an essential safety practice for any driver, especially for those operating commercial vehicles. The correct answer emphasizes the importance of ensuring that there is enough space in the adjacent lane before you begin the lane change. By checking your mirrors beforehand, you can assess the position and speed of other vehicles, which helps prevent collisions. This action allows you to make an informed decision about whether it’s safe to proceed with the lane change. It also gives you the opportunity to spot any vehicles that may be in your blind spots that you might not see directly in your peripheral vision. Thus, mirroring this behavior aligns with safe driving practices and is a crucial step in the lane-change procedure. The other options imply checking mirrors at inappropriate times, which can increase the risk of an accident. Checking after starting the lane change, for example, does not provide the necessary awareness before making the move and could lead to unsafe situations. Similarly, only checking after completing the lane change or when merging onto a highway ignores critical opportunities to ensure awareness of surrounding traffic at various stages of driving.