Final answer:
The safe thing to do when driving through a tunnel is to turn on your headlights. This ensures increased visibility for the driver and other road users. Other options, like using a cell phone, increasing speed, or closing your eyes, are unsafe and increase the risk of accidents.
Step-by-step explanation:
When driving through a tunnel, one of the safe things to do is turn on your headlights. This action increases visibility within the confined space of a tunnel, not only for you as a driver but also for other road users. It is essential for safety reasons to keep your eyes open and remain fully alert. Increasing speed is unsafe due to the limited visibility and potential for sudden traffic changes. Using your cell phone is dangerous and can be a distraction, leading to accidents, especially in an environment where concentration is paramount. Moreover, it's advised to use hands-free devices if you need to communicate while driving to decrease any additional risks. Needless to say, closing your eyes while driving is extremely dangerous and should never be done. Safety measures such as wearing seat belts and avoiding unnecessary risks apply at all times when driving, regardless of whether inside or outside a tunnel.