What is a key safety measure to take before entering a tunnel?

Ensuring all passengers have their seatbelts on before entering a tunnel is a crucial safety measure. Seatbelts are fundamental in protecting occupants of a vehicle in the event of a sudden stop or collision, which can be more likely in the confined space of a tunnel. In tunnels, visibility may be reduced, and the potential for accidents can increase due to factors such as reduced reaction time or increased traffic density. By confirming that all passengers are secured with seatbelts, the driver takes an essential step to protect everyone in the vehicle against the risks associated with driving through a tunnel.

While it is also important to adjust the seat position for comfort and proper control, check for obstacles, and ensure lights are functioning for visibility, those actions may not directly address the immediate safety of all vehicle occupants in the event of an incident while in the tunnel. Hence, the primary focus on seatbelt use underscores the significance of personal safety in such environments.