What should you do when you no longer see a car approaching from behind while planning to change lanes?

When planning to change lanes, looking over your shoulder to check your blind spot is the proper action because it ensures you have a full understanding of the traffic situation around you. Even if you believe there is no car approaching from behind, it's essential to physically check your blind spot, as there may be vehicles you cannot see in your mirrors.

This careful precaution helps confirm that it is indeed safe to change lanes and prevents potential accidents or collisions. The act of considering all surrounding vehicles and obstacles demonstrates responsible driving behavior and adherence to safe driving practices.

Other options suggest actions that could lead to unsafe situations, such as changing lanes immediately without checking or speeding up without confirming that the lane change is safe. These might show a lack of caution and awareness of the driving environment, which are crucial for a safe driving experience.