Challenges in Decarbonising Winter Road Maintenance

Although the Centre of Excellence is focused primarily on decarbonising materials, as part of ADEPT Live Labs 2: Decarbonising Local Roads in the UK is a three-year, UK-wide £30 million programme funded by the Department for Transport that aims to decarbonise the local highway network, local authorities (LAs) are tasked with decarbonising road maintenance through a holistic lens, including methods, plant, fleet and materials. There is no case where this is truer than with winter road maintenance, where positive change comes less from material switches and more from service optimisation. In this article we explore trials, tribulations and solutions.

1. Carbon Emissions & Environmental Impact 

Research by WSP found road transport to be the most significant contributor to pollution within the transportation sector and while winter maintenance is essential, the service can produce high carbon emissions. Currently HGV gritters contribute greatly to high carbon emissions in winter maintenance, as LAs up and down the country deploy their winter fleet on to their networks daily from November to April, to carry out vital winter actions. In addition to this, the rock salt and other de-icing material that is currently being used has a negative and corrosive impact on the environment as it often causes ground contamination in roadside verges, is washed into road drainage systems and on into local watercourses, and accelerates the ageing process of assets, such as bridges, signposts etc. 

2. Forecasting 

LAs work tirelessly throughout the year to ensure their local roads and footways remain safe to drive, wheel or walk on. This can be challenging due to the unpredictability of the weather, particularly in winter.  The Institute of Highways Engineers reports that adverse weather conditions during recent winters have significantly impacted the travelling public and local economy, therefore winter operations are essential in minimising the impact of weather on our roads, but this is not without costs and demands. 

Weather stations with camera facilities can provide real time weather information allowing forecasters and LAs to monitor and provide a real time visual of the condition of their local network.  Around midday, each LA receives a daily forecast and subsequent forecast updates from their chosen provider in both text and graph formats which show the predicted road surface temperatures over a 24-hour, 36-hour or 48-hour period. On receipt of the forecast, each LA then decides upon the appropriate winter action, which is passed on and delivered by their winter fleet. Through continuously monitoring their routes and forecasts, LAs can provide a more focused winter service. 

3. Solutions to Decarbonising our Winter Services 

All LAs are continually striving to lower carbon emissions produced by their winter maintenance whilst still balancing political and public pressures, and as the world reduces its carbon emissions by moving towards electric vehicles (EV), it is yet to be determined if this innovation would be favorable for gritters. Gritters often deal with intense weather/ snow conditions – a challenge which an EV gritter may not currently be equipped to handle. With the first fully electric gritter coming to market at the beginning of 2024, LAs continue to explore the adoption of EV gritters to their fleets. 

In the interim, adaptations are being made to enhance the performance of gritters to reduce their carbon footprint, for example, equipping gritters with improved ceramic blades on ploughs, which improve snow clearance. Additional advancements have included the use of new technology such as on board vehicle temperature sensors which dynamically measure the road surface temperatures to produce a more focused gritting action via automated gritting. 

Advanced route rationalisation software can review designated routes and can decrease the distance travelled by reducing journey overlap among gritters. Continuing to minimise the distance travelled by gritters, salt capacity is maximised for each gritter, decreasing trips back to the depot to reload. Additionally, reviewing spread rates where possible, can have a significant impact on salt use.  

Advancement in scanner technology that can determine the skid resistance/ ice on roads allowing LAs to build data on various gritting routes. This data allows LAs to reduce salt spread rates and amount of treatments on specified routes which would drive a reduction in the material used to treat the public network, thus supporting carbon reduction. 

Additionally, the use of additives that are added to the rock salt can be advantageous in lowering carbon emissions in winter maintenance as it makes the gritting treatment more effective by helping the salt adhere to the road longer. As part of the Live Labs 2 project, we are conducting trials with WinterPave, an additive incorporated into the road surface course. This additive possesses de-icing properties, eliminating the necessity for the surface to be treated to prevent icing. 

As all LAs tackle these challenges, they continue to explore low carbon options and methodologies used in other countries.  The Centre of Excellence for Decarbonising Roads are working closely with Connected Places Catapult, the UK’s innovation accelerator for cities, transport and place leadership, to identify lower carbon operational and material innovations. 

As we journey towards NetZero we are already seeing progress and through rigorous testing and evaluations, this collaborative programme can hopefully discover more sustainable ways of delivering winter road maintenance in the UK and beyond.  

If you are facing similar challenges, contact CEDR to discuss options on LinkedIn @CentreofExcellenceforDecarbonisingRoads or via our website https://decarbonisingroads.co.uk/