Important road safety principles for tunnels include careful design of the tunnel entrance and exit, proper lighting, limiting ramps and tight turns, and proper drainage. Emergency lanes increase the space to the tunnel walls, and allow vehicles with breakdowns to stop safely. However, emergency lanes are generally not used in tunnels for cost-effectiveness reasons. Finally, discontinuities (merge and exit lanes, splits, weaves, lane terminations and additional lanes) should be avoided both near tunnels and in tunnels themselves, especially where emergency lanes are not provided.
For more information on tunnel safety, see the archived SWOV fact sheet The road safety of motorway tunnels and information on Rijkswaterstaat’s Steunpunt Tunnelveiligheid (Tunnel Safety Support Center). The Richtlijn Ontwerp Autosnelwegen (Design Standards for Motorways) (ROA, 2019) contains design guidelines for tunnels.
