Harmful Emissions

Clean air is vital for people’s health, the environment and the prosperity of cities, which need to be desirable places to live and work. The current surface transport system contributes significantly to air pollution. Our mission is to help the sector reduce its CO2 and NOX footprint and contribute to the UK’s Road to Zero plan.

Air quality

Since the early 1970s, TRL has been monitoring air quality to assess the levels of pollutant from vehicle exhausts. We have worked to understand how traffic flows, speeds and road layouts contribute. Today, our environmental experts assist local authorities, government and transport planners to measure, model and analyse air quality and emission. This provides information that informs clean air zone policy.

We don’t just support the transport industry. We work closely with the Environmental Agency and Public Health England, monitoring the impact of large commercial fires on the surrounding air quality. Recently, this included the tragic collapse of Grenfell Tower, the Kidderminster recycling facility and Sunderland Waste Storage.


On behalf of the European Commission, we investigated innovative electric bus and wireless charging technologies for seven European cities. The Zero Emission Urban Bus System (ZeEUS) project gave cities guidance on how to introduce electrified bus systems efficiently. This offers a viable and less polluting alternative to diesel and petrol fuelled transport.

The Consumer, Vehicle and Energy Integration Study explores the public’s attitude to buying electric vehicles and the impact of charging them on the energy network. We’re leading the project: our findings will inform policy recommendations as the nation seeks to move to a secure and sustainable low carbon vehicle fleet.

Working alongside the World Roads Association (PIARC), we evaluated the technical and economic feasibility of electric road systems. We reviewed inductive, conductive and conductive rail technologies and how highway authorities might adopt and maintain them. Our recommendations may help road authorities develop sustainable and efficient electric roads for key road freight routes.


For more than a decade, we’ve been managing the ECO Stars Fleet Recognition Scheme, which aims to help fleet operators improve efficiency, reduce fuel consumption and emissions. We now manage and operate over 26 schemes for Barnsley Metropolitan Borough Council. Each one saves up to £2,450 per vehicle and improves efficiency as much as 5%.

Recently we conducted a study into zero emission heavy goods vehicles (HGV) technologies for Highways England and the Department for Transport. It investigated alternative fuel options for HGVs and evaluated other proposed technologies for long-haul HGV movements by 2040.

TRL provided independent, technology agnostic assessment of 19 demonstrators for low and zero emission vehicle technologies. Funded by Innovate UK, they comprised compressed natural gas vehicles (biomethane and mineral), hydrogen-diesel dual fuel, battery electric, lightweight aerodynamic trailers and kinetic energy recovery systems (KERS). We’re carrying out an extensive emissions test for a cross section of the test vehicles, monitoring and evaluating the potential impact on improving air quality. These programmes are amongst the largest real-world demonstrations of low and zero emissions freight and logistics technologies seen in the UK - proving that there are viable alternatives to diesel drive train HGVs.

We are evaluating and quantifying the potential benefits of reduced emission levels from freight platooning. The UK’s HGV Advanced Platooning Trials are managed by TRL on behalf of the Department for Transport and Highways England.

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