What action should a driver take if their vehicle breaks down in a tunnel?

When a vehicle breaks down in a tunnel, the safest and most appropriate action is to use the emergency telephone to call for help. Tunnels are confined spaces with limited ventilation and potential hazards, making it crucial to notify the authorities to manage the situation safely.

Using the emergency telephone ensures that qualified personnel are alerted and can respond promptly, including traffic management and rescue services. This reduces the risk of accidents occurring as other vehicles navigate around the broken-down vehicle.

Choosing to flag down a passing vehicle could lead to confusion or additional danger, as motorists may not be prepared to stop safely in such an environment. Pushing a car out of a tunnel can pose significant safety risks both to the driver and to other road users. Using a flare might be a common method in other scenarios but is not ideal in a tunnel due to the specific risks associated with fire and smoke in enclosed spaces. Thus, calling for help through the emergency telephone is the most effective and safest choice.