Following significant landslides in 2020, a bespoke operational strategy has been implemented to facilitate the safe use of the A83 corridor at the Rest and Be Thankful. The questions and answers below explain the issue in more detail.
Where exactly is the Rest & Be Thankful located? The Rest and Be Thankful is located on the A83 in Argyll and Bute and is situated between Arrochar and Inveraray. The stretch of road is over 240 metres above sea level and passes through Glen Croe. The current A83 was constructed in the 1930s and is cut into the side of the hill. It replaced the historic Old Military Road which runs along the valley floor with a steep hairpin section at the north end of the Glen.
How are landslides triggered in the area? Landslides are triggered by heavy rainfall or snow melt and normally occur after prolonged wet periods. This causes over-saturation of the ground that can lead to debris slides.
How many landslides have there been? Since 2007, 47 landslides ranging in severity from very minor slips with no impact on the road to significant debris flow events have been recorded. This includes the two major events in August and September 2020, where a combined total of 16,000 tonnes of material was estimated to have been displaced from the hillside.
What has been done to reduce the impact of landslides?
The Old Military Road has been improved to allow it to be used under convoy control as a local diversion in the event of a landslide, or if there are concerns about hillside conditions on the A83.
Various mitigation measures have been implemented to help prevent debris from reaching the A83, including debris fences, roadside catch-pits, and drainage improvements. To date, six catch-pits have been constructed adjacent to the A83.
A temporary bund has also been constructed adjacent to the Old Military Road below the area affected by the 2020 events to afford greater resilience to the local diversion route.
How is the landslide risk being monitored? Operational management of the A83 is considered daily to ensure the safe passage of vehicles. Detailed weather forecast information, saturation estimates, slope monitoring and on-site inspections by geotechnical engineers are being used to monitor hillside conditions and ensure safe road operation.
What traffic managements arrangements are in place on the A83? Road user safety is paramount, and BEAR Scotland and Transport Scotland consider forecast conditions and live information from the site on a daily basis to determine the most appropriate measures to protect road users. Where conditions are predicted to affect the safe operation of the A83, the Old Military Road can be utilised as a local diversion route through Glen Croe under convoy control. Read more here about the range of traffic management responses that are being utilised.
Is there a diversion route if the A83 is impassable? If it is safe to use, the Old Military Road Local Diversion is used under convoy control. Only in exceptional circumstances is the long diversion route via the A82/A85/A819 considered for use.
How long is the diversion route? The Old Military Road Local Diversion is no longer than the route on the A83 although as it is operated under a convoy, it normally takes 15 to 20 minutes as opposed to 3 to 6 minutes on the A83.
In exceptional circumstances when the longer diversion route is used, this can add a maximum of 60 miles in total to your journey. However, depending on where you are coming from and going to, many journeys are extended by around 30 miles. This has not been required since 2021.
Why is the Rest and Be Thankful particularly impacted by bad weather? The type of soil, the steepness of the hillside and the positioning of the A83, combined with the climate of Argyll means the location is particularly prone to landslides which can impact the operation of the trunk road.
Are works currently underway at the Rest and Be Thankful? The most recent phase of works has now been completed and traffic reverted to two-way operation on the A83.
What should the traveling public be mindful of when planning a journey via the Rest and Be Thankful? Full closures of the A83 remain relatively rare. However, road users are asked to plan their journeys utilising the most up to date travel advice available from the Traffic Scotland website: A83 Rest and Be Thankful | Traffic Scotland. This tells you what the traffic management arrangement is on any day and gives an indication of what your journey time through the Glen may be.