Tailgating is dangerous primarily because it reduces your reaction time and increases the risk of rear-end collisions. When you follow another vehicle too closely, you have less time to react to sudden stops or changes in speed, which can lead to accidents. Maintaining a safe following distance allows you to properly gauge the speed of the vehicle in front of you and gives you the necessary time to react if they brake unexpectedly. This is critical in preventing collisions and ensuring the safety of all road users.
In contrast, the other options present misconceptions about tailgating. For example, tailgating does not improve visibility; in fact, it often obscures your view of what is happening on the road ahead. Additionally, it does not make driving more efficient, as it could lead to unnecessary accidents. Furthermore, tailgating is not permissible in heavy traffic, as it still poses a considerable risk and can exacerbate traffic issues. Hence, avoiding tailgating is essential for safe driving.