The peak organisation of Australasian road transport and traffic agencies, Austroads, identifies factors that contribute to the occurrence and severity of collisions adjacent to and within tunnels and suggests remedial treatments. The objectives of this study were to identify factors that contribute to the occurrence and severity of collisions adjacent to and within tunnels and remedial treatments that will reduce the incidence and severity of these collisions.

Michael Tziotis, Tariro Makwasha, Blair Turner and Dr Michael Regan have prepared the report and Geoff McKernan is the project manager.

The main findings in the study were that driver behaviour is a major factor in the occurrence of collisions on the approaches to and within tunnel and most collisions involve vehicles travelling in the same direction.

The main collisions risk factors are changes in driving conditions, variations in light levels and/or ‘quality’ of lighting, trucks travelling through tunnels, the absence of a shoulder and last but not least merge and diverge areas in tunnels. 

To address the factors that increase collision risk and collision severity the Austroads have provided following conclusions and recommendations:

• Type and placement of signage should be reviewed
• Lighting levels upon entry to tunnels, and through the transition zone, should be reviewed and regulated
• Increased use of variable message signing (VMS) as a means of informing and advising users of incidents and driving requirements
• Review of truck access to tunnels and/or introduce restrictions on lanes
• Speed cameras for all tunnels
• Increased use of VMS or static signing to avoid overtaking, but also to maintain a safe distance between vehicles
• Provide shoulders or breakdown bays, or ensure that safety management systems are provided to reduce collisions risks associated with their absence
• The application of low-cost perceptual countermeasures treatments should be investigated as a means of affecting safe driver speed behaviour, improving lane discipline and safe driver headways.

Further on the report recommend that the national guidelines should be reviewed to ensure that it reflects best practice in the construction of new tunnels and in the retrofitting of older tunnels.

While tunnels are relatively safe when compared with other parts of the road network, crashes in or near them are a significant source of road trauma and cause substantial delays to road users across the road network. The Australian Road Authorities highlights that the tunnels is an important part of the road network, and there is a need to ensure motorists can travel in a ‘Safe System’ consistent with the National Road Safety Strategy in Australia. 

Reference:

Measures to Reduce Crashes Adjacent to and within Tunnels | ISBN 978-1-925671-24-7 | Austroads Project No. TT1972 | Austroads Publication No. AP-R557-18 | Publication date January 2018 

 Weblink: 

https://www.onlinepublications.austroads.com.au/items/AP-557-18 (Report)

http://www.austroads.com.au/road-construction/road-tunnels/guide-to-road-tunnels (Guidelines)