What is the first action you should take before merging into another lane?

Before merging into another lane, the most crucial first action is to check your mirrors and blind spots, then signal your intent. This methodical approach ensures that you are fully aware of your surroundings and any vehicles that may be in your blind spots, which are areas not visible through mirrors.

Using mirrors alone is not sufficient because they do not cover every angle, especially the areas directly beside and behind your vehicle. By checking your blind spots, you minimize the risk of a collision with vehicles that may be in your path. Signaling your intent is equally important, as it communicates your plans to other road users, allowing them to anticipate your actions and adjust their driving accordingly. This combination of awareness and communication promotes safety and smooth traffic flow, making it an essential step in merging safely into traffic.

Other options, such as just signaling or looking only in the side mirror, would not provide a comprehensive evaluation of the driving environment, which is necessary for safe merging. Similarly, speeding up to match the flow of traffic should only be considered once you have assessed that it is safe to do so.