The launch of the tool comes as EU judges are told that the UK is to break nitrogen dioxide limits until at least 2030 – more than 20 years after the original deadline – despite the fact that the Government previously said that limits would be met by 2025.

Aimed at tackling the issue of rising NOx levels, the Clean Vehicle Technology Fund provides support and guidance, with a total of £5m available for Local Authorities to help fund improvements to local bus and vehicle fleets.

As part of the scheme local authorities are required to document how they will monitor and evaluate real-world emissions. This could include the use of a realistic test cycle, as well as portable emission monitoring systems or on-street monitoring.

However, in response, Emissions Analytics warns that the EU regulations for both NOx and miles per gallon are calculated using the New European Drive Cycle test, which provides theoretical emissions figures for each vehicle but fails to predict the real-world emissions of vehicles when used on public roads. The firm believes that on average the deficiency between official and real world emissions figures is 22%.

With air quality assessment monitored by roadside gas analysers, which record ambient pollution, this could mean that local authorities may inadvertently allocate funds to vehicles with much higher emissions than promised.

Emissions Analytics is developing a new traffic simulation model that will calculate the effect of speed and congestion on fuel economy, as well greenhouse gas (CO2) and air pollution (NOx and CO) components. Underpinned by the data from its real-world tests, this advanced simulation helps local authorities select the best vehicles.

‘Choosing a vehicle on the basis of its theoretical emissions, without understanding how it operates in the real world, is a lottery,’ said Nick Molden, founder and CEO of Emissions Analytics. ‘It’s quite possible to select a vehicle that theoretically will help reduce NOx emissions, only to find that it has a negative impact on real-world emissions.’