Case study - LED Lights

Transport Scotland has ‘LED’ the way on the road to carbon reduction


Transport Scotland, which is solely responsible for the management of a wide range of roadside electrical assets (REAs) across the country’s trunk road network such as road lighting, illuminated signs, illuminated bollards, intelligent transport systems and traffic signals, is committed to its ambitious vision to create a best-in-class Network Operations Service with carbon reduction at the heart of its approach.

As part of this, road lighting was identified more than five years ago through Transport Scotland’s Carbon Management Plan as the largest REA consumer of energy by around 80% and was therefore prioritised as one of its key projects for further reducing emissions.

The organisation established a five-year programme to convert all road lighting from the standard typical high intensity discharge luminaries to light-emitting diodes (LED) type luminaries.

Upgrading to LED provides state-of-the-art lighting operating at greatly reduced levels of electrical consumption whilst also providing improved colour rendering and reduced light pollution. The sophisticated remote control and monitoring of the lighting with the inclusion of Lighting Central Management Systems (L-CMS) facilitates effective control of lighting so that it also has the potential to be dynamically adjusted to the appropriate levels under the influence of traffic, weather, or incident conditions, thereby materially contributing to country wide network resilience.

Transport Scotland’s Carbon Management Plan takes into account both operational (utilities, business and commute travel, waste and water) and network energy emissions (Trunk Road REAs). It set two corporate reduction targets, based on 2015/16 figures:

  • To reduce operational emissions by 20%
  • To reduce Network Energy emissions by 25%.

A key project in achieving this target, as well as contributing significantly to the Scottish Government’s Energy Efficiency action plan, has been the LED lighting conversion project.

The Challenge

With a complex mix of factors to get right and ensure Transport Scotland delivered on the objectives and more, implementing a project of this scale through to completion can be a major challenge due to a number of reasons including:

  • Logistics & timescales
  • Public safety and security
  • Avoiding/minimising disruption
  • Mitigating any impact on biodiversity, townscapes and journey ambience and social inclusion
  • Sustainability
  • Cost effectiveness

The Solution

Utilising a model developed by infrastructure specialist, Scottish Futures Trust – one which was independently verified by PwC – Transport Scotland was able to model various scenarios and timeframes to give insight into spreading investment.

Early trials of LED luminaires provided valuable lessons going forward to ensure the lighting best met the needs and aspirations of the communities they serve. Following the trials, the luminaires utilised were fully designed to the circumstances of each location, such as road type, column height and spacing, to ensure provision of appropriate lighting. 

Trial upgrades were then undertaken at various junctions, including the A96 along a section of the High Street in Elgin, Morayshire. This trial was highly successful with energy consumption being reduced by 23% with approximate savings of 76 kgCO2e per light, per annum.

Disruption was minimised due to the LED luminaries being designed and installed onto existing lighting columns.

The Result

Transport Scotland met its 5-year reduction target within two years, following the the Public Bodies Climate Change Duties report published in late 2018.

In the first year alone, Transport Scotland reduced Network Energy emissions associated with lighting on the Trunk Road Network by 22% and by the end of the financial year 2020/21 emissions have reduced by over 70%, dropping from 20847 tCO2e in the baseline year to 6103 tCO2e.

The success of the LED project and that of Transport Scotland’s Carbon Management Plan and associated projects has been acknowledged with several environmental and efficiency awards. These include the Large Scale Project category for the LED replacement project at the 2019 Scotland Region Energy Efficiency Awards with the project also shortlisted as a finalist for the Environmental Sustainability in the Highways Sector’ category.