What action should be taken if a vehicle is in your blind spot?

The action of checking again before changing lanes is crucial for ensuring safety while driving. Blind spots are areas around your vehicle that are not visible through your mirrors, meaning that other vehicles could be present in those areas without you realizing it. By checking again, you can look over your shoulder to confirm that there is indeed no vehicle in your blind spot, as this additional check provides a more comprehensive view compared to relying on mirrors alone.

The other choices may lead to hazardous driving conditions. Changing lanes immediately could result in a collision if another vehicle is occupying the space you are trying to move into. Ignoring the blind spot could have serious consequences, as it heightens the risk of an accident. Slowing down can be a prudent action in certain situations, but it does not specifically address the need to verify that the lane is clear when considering a lane change. Therefore, the most responsible and safe course of action is to check again before making any lane changes.