What is the main disadvantage of following too closely behind another vehicle?

Following too closely behind another vehicle significantly reduces your reaction time if the vehicle in front suddenly stops or slows down. This situation is critical because it gives you less time to respond and maneuver safely. Maintaining a safe following distance allows you the necessary time to react, whether that means slowing down, changing lanes, or stopping entirely to prevent a collision.

While there may be increased fuel consumption due to rapid accelerations and decelerations when tailgating, or potential visibility issues regarding traffic signs because of proximity to other vehicles, the primary concern is safety. Other vehicles blocking traffic signs might also lead to distractions, but these factors do not pose as immediate a risk as the reduced reaction time when driving too closely.