A82 Tarbet to Inverarnan

The Scottish Government's Strategic Transport Projects Review identified a number of measures to reduce congestion and improve traffic flows along a number of sections of the A82. 

The route between Tarbet and Inverarnan runs adjacent to the west bank of Loch Lomond for 17 km (10.6 miles).

It is located within the Loch Lomond and The Trossachs National Park in an area of outstanding natural beauty. It is a complex site, physically constrained, with the loch on one side, and the hillside and railway on the other. All feasible upgrade options will be reviewed to ensure value for money.

The study will consider issues including:

  • the impact of widening the road
  • opportunities to improve visibility and reduce the levels of accidents
  • improving drainage
  • pedestrian and cycle access
  • car parking and lay-by provision
  • delivering journey time reliability

A82 Tarbet to Inverarnan Route Corridor Plan

The £2 million design and survey work started in summer 2013 and was completed in September 2015 with the identification of a preferred route option. The work looked at a range of issues, including:

  • environmental impact
  • ground investigation
  • traffic impact
  • economic assessment
  • value for money

The study followed an objective led approach  informed by consideration of the problems and constraints. 

Stage 1 Assessment - Preferred Route Corridor

The Design Manual for Roads and Bridges (DMRB) Stage 1 assessment to identify a preferred corridor agreed specific Transport Planning Objectives (TPO) that best defined what the scheme is trying to achieve. 

The five TPOs developed were:

  1. To improve journey times for A82 trunk road users between Tarbet and Inverarnan (based on observed post Pulpit Rock scheme).
  2. To reduce personal injury accident numbers and their severity on the A82 between Tarbet and Inverarnan to be closer to or better than national KSI (Killed or Seriously Injured) rates.
  3. To provide appropriate stopping opportunities for visitors and for all trunk road users on the A82 between Tarbet and Inverarnan taking account of the unique setting of the route within the National Park.
  4. To seek to provide opportunities for enhanced access by sustainable modes of travel along the A82 corridor between Tarbet and Inverarnan.
  5. To reduce disruption to road users resulting from the undertaking of maintenance activities on the A82 between Tarbet and Inverarnan.

A wide range of route corridors were identified and following an initial sifting process using the above objectives, the three most feasible route corridors were narrowed down to:

  • Route Corridor 1 - the existing A82 route corridor
  • Route Corridor 2 - a route corridor from Arrochar to Inveruglas along Glen Loin to where it joins the existing A82 route corridor
  • Route Corridor 3 - a route corridor above and to the west of the West Highland Rail line

An assessment of the engineering challenges, environmental effects and traffic and economics concluded that Route Corridor 1 (A82 on-line, the ‘red route’ - see plan above) was the preferred corridor.

Other options, such as a straight line tunnel through the hillside or a submerged tunnel in the loch were also considered, but sifted out at an early stage because they failed to meet all of the objectives. It is also notable that the £4 billion estimated cost of the tunnels was considerably higher and would have provided a significantly lower economic return than the other options.

A leaflet providing further details of the preferred route corridor was distributed to stakeholders and landowners.

The project advanced to DMRB Stage 2, with the assessment and identification of a preferred route within the corridor. 

Stage 2 Assessment - Preferred Route

The DMRB Stage 2 preferred route assessment work is now complete.

A number of route options and sub options were considered and sifted. Four route options were then developed for assessment as follows:

  • Route Option 1 – an online route
  • Route Option 2 – an online route with inland sections
  • Route Option 3 – an online route with over-loch sections
  • Route Option 4 – an option with fewest bends

A plan of the route options assessed is provided in the link below:

Based on the route options assessment process, Route Option 1 – online upgrade – is to be taken forward as the preferred route option. Further consideration will be given to the following, as part of the design and development of the preferred route option (DMRB Stage 3 assessment process):

  • Inclusion of two short off-line sections near Ardvorlich
  • The alignment will be developed to reduce impact on properties and landowners
  • The alignment will also be adjusted to assist construction and reduce delays to road users
  • A carriageway width of 6 metres and 7.3 metres (both with 1 metre hardstrips) will be considered

An indicative plan of the preferred route option is provided in the following link:

A public exhibition was held at various venues to present the preferred route option.

Public Exhibitions

Public Exhibitions were held on Wednesday 30 September at Arrochar, Thursday 1 October at Crianlarich , Friday 2 October at Oban and Tuesday 6 October at Fort William. View the exhibition materials below.

What Happens Next?

Transport Scotland will now take forward the development and assessment of the preferred route option to DMRB Stage 3.

The next stage of the assessment process will include:

  • Consultation with stakeholders, affected landowners and the general public
  • Design development of the preferred route option
  • Identification of the land required for the scheme and preparation of Draft Orders which will define the line of the developed preferred route option
  • Environmental impact assessment of the developed preferred route option and preparation of Environmental Statement
  • Development of suitable mitigation measures to reduce impacts on the environment

As part of the work to improve this section of the A82 in advance of the upgrade scheme, Transport Scotland and the trunk road operating company, BEAR Scotland, will also be undertaking an intensive programme of short-term improvements which will include vegetation and tree canopy clearance, clearance and improvement of the existing drainage system, and the removal of loose stones and rocks from the verge of the existing A82. The feasibility of further medium-term interim improvements – such as localised schemes to widen the road at tight bends and additional improvements to the drainage system along the route – will also be investigated.

How to get involved

Transport Scotland and CH2M - Fairhurst Joint Venture are working closely with Loch Lomond and the Trossachs National Park, Argyll and Bute Council, Scottish Natural Heritage, Scottish Environment Protection Agency, Network Rail, community councils and others in undertaking the study.

We are also talking to groups representing all users of the A82.

Stakeholder workshops were held at the Three Villages Hall in Arrochar on 2 October 2013, 29 May 2014 and 20 November 2014.

Public exhibitions of the Stage 2 preferred route were held at Arrochar, Crianlarich, Oban and Fort William to give the public the opportunity to see the preferred route option.


A drive through video of the stretch of the A82 between Tarbet and Inverarnan can be viewed on YouTube. and a computer generated 3D fly through can also be seen on YouTube.