Aggressive driving on average increases pollutant emissions by 35% in rural conditions and by around five times on the motorway, according to tests by Emissions Analytics.

The analysis found even higher 'hotspots' where emissions at high speed can peak at more than 10 times typical levels of NOx.

The need to identify hotspots is becoming vital with the new Real Driving Emissions (RDE) regulations, which is a much tougher regulation of driving in normal conditions, said Emission Analytics.

To help quantify that risk, Emissions Analytics is launching a new evaluation programme to quantify the risk of excessive emissions for each vehicle tested.

Currently, EQUA Index ratings are published to allow the performance of different vehicles to be compared on a standard, normal cycle.

The new programme leaves that rating unchanged, but puts the vehicle through an extended test designed to measure performance in more extreme and unusual driving conditions.

The variance between that, the standard EQUA Index and the regulated level will yield a rating for the risk of exceeding the regulated level.

The main factors considered are:

• Higher speeds
• Higher and lower rates of acceleration
• Cold start emissions
• Emissions under regeneration of the diesel particulate filter.

Emissions Analytics said these results are important for cities, manufacturers and regulators.

For cities, it is vital to know that the latest vehicles do not have emissions hotspots that could undermine their air quality targets.

For manufacturers facing third-party RDE testing to check compliace, it is important to quantify the risk of high emissions being found in unusual driving conditions, where every scenario cannot practically be tested.

For regulators, it is important that RDE is seen to fundction well in order to draw a line under the failed regulation of the past.