Driving through tunnels requires careful attention to specific rules and environmental changes to ensure safety. This guide highlights essential considerations for driving through tunnels, from adapting to lighting and airflow changes to understanding critical signage. Learn about mandatory speed limits, the crucial difference between headlights and daytime running lights, and safe following distances – including the 100-metre minimum for cars and 150-metre minimum for HGVs. We also cover lane indicators and prohibited overtaking in two-way tunnels, ensuring you’re fully prepared for safe passage.