What risk analysis has been undertaken of the impact on the B3181 in the event of a closure of the M5 (caused by an accident) between Cullompton and Exeter resulting in traffic being diverted via the B3181? What risk mitigation is in place in the event that motorway traffic has been diverted and temporary roadworks traffic lights are in place?
Closures of any part of the national strategic road network are managed by National Highways who will liaise with the relevant highway authority on to who’s roads traffic will be diverted.
Agreed contingency diversion routes exist for any such closures of the strategic road network (in this case the M5) between the local highway authorities (in this case Devon County Council) and National Highways.
While street works activity cannot be barred from such routes, the risks are acknowledged and ameliorated as far as reasonably practicable relative to the nature and type of works being promoted.
Strategic diversion routes (in this case the B3181) show up electronically on the permit register with a special designation to promoters when raising a works application on the route and to the authority when assessing.
If planned road works activity is to take place on a road which is a contingency diversion route for the M5, liaison takes place with the promoter around what contingency measures they can use when a permit application is assessed.
This can mean prompt removal of the site from the road or the use of road plates over an open excavation on site to allow two-way traffic if this is both appropriate and feasible.
When unplanned works activity occurs i.e. an immediate (urgent or emergency) requirement, liaison will take place dynamically with the promoter while on site should a need to use the diversion arise.
When immediate (urgent or emergency) works occur to prevent damage or injury or to restore a service, the promoter (as a statutory undertaker) has a legal right to access their apparatus to repair or maintain utility services.
In such immediate instances, the promoter can legally commence operations to prevent damage or injury to persons or to restore a service and is only required to inform the highway authority within 2 hours of starting on site.