A83 Rest and Be Thankful - Managing Trunk Road Operation

History

The A83 through Glen Croe in Argyll, known historically as The ‘Rest and be Thankful’ has a history of landslides which have impacted the operation of the A83 trunk road. The A83 is a lifeline route linking the people and businesses of Argyll with the central belt of Scotland. The geology of the area, the location of the road and the weather conditions experienced leads to a higher-than-normal number of landslides which can range from a few tonnes to over 10,000 Tonnes in a single event.

For over ten years, since the events became more regular and larger in scale, Transport Scotland have invested in the construction of significant landslide mitigation measures including robust debris fences and debris pits. These measures now cover all the main water channels on the hillside.

Following the largest recorded landslides; 6,000 and 10,000 Tonnes – both in 2020, further mitigation work and in depth monitoring has been undertaken and a management strategy implemented to ensure the safe operation of the A83.

Current monitoring regime

Following the completion of the latest phase of mitigation works the temporary traffic management has been removed and the road is currently operating unrestricted in both directions.

The daily management of the route though is continuing behind the scenes, to ensure it is safe each day for road users.

BEAR Scotland, through the use of innovative technology, remotely collects and reviews a range of detailed information including:-

  • Expert weather forecasting data
  • Highly detailed timelapse photography showing hillside condition and watercourse flows which allows comparison with previous images
  • Local weather station data recording recent rainfall and road conditions
  • Ground saturation estimates

Daily decision-making

This information is reviewed daily to consider the best mode of road operation over the next 24 hours and over the next five days thereafter. These daily reviews can lead to one of the following decisions:

  • No action required – traffic unrestricted. (This happens most of the time.)
  • A precautionary site inspection is suggested, over and above the remote monitoring at various frequencies. Traffic unrestricted. (This happens regularly.)
  • Site inspection plus the precautionary regular patrolling of the road to check for signs of hillside movement. Traffic unrestricted. (This happens occasionally.)
  • The use of the Old Military Road local diversion at night under a traffic convoy arrangement. (Used occasionally.)
  • The use of the Old Military Road 24 hours a day. (Occasionally.)
  • The use of the long diversion via the A82, A85 and A819. (Very rarely, normally only once a landslide has occurred.)

Use of the Old Military Road

During periods of very inclement weather and/or when there have been many days of wet weather and the hillside is judged to be very saturated, traffic will be diverted onto the Old Military Road local diversion.

When the Old Military Road local diversion is being used traffic signs will divert traffic onto the diversion route at the south end. The south section of the route is two-way with speeds restricted to 15mph. Traffic signals cover the extents of the north section of the diversion route which operates under convoy due to the width and bendiness of the road. A vehicle travelling at 10mph escorts vehicles through this narrow section, one direction at a time.

The Old Military Road local diversion is similar in length to the A83 but as it is operated under a convoy, it normally takes 15 to 20 minutes to drive as opposed to 3 to 6 minutes on the A83.

A dedicated recovery service will be stationed on site to attend to any incident or breakdown free of charge.

Communications

Various communication channels – including stakeholder updates, media releases and social media updates are used to highlight significant changes to operational arrangements on the A83 at the Rest and Be Thankful, to keep interested parties informed.

Road users are encouraged to plan ahead before setting out on their journey and should obtain up to date information from Traffic Scotland at www.traffic.gov.scot or on Twitter at @trafficscotland.

Major project

Transport Scotland is progressing the Access to Argyll and Bute (A83) project which is looking at developing a more resilient and sustainable route to Argyll and Bute, and a longer-term solution to the challenges at the Rest and Be Thankful.
More information on the project and possible route options can be found on the Transport Scotland website here.