Euro 6 diesel cars emit twice as much nitrogen oxide per litre of fuel than trucks and buses in real-world driving conditions, new data has claimed.
According to research from the International Council on Clean Transportation – a body heavily involved in exposing Volkswagen’s dieselgate scandal – heavy-duty trucks and buses emit 210mg of NOx per kilometre in real-world conditions, compared with the 500mg NOx/km pumped out by Euro 6 diesels in the same conditions.
The group put the large difference down to the differing testing regulations. Since 2013, mobile testing devices became mandatory during bus and truck testing so that randomly-selected vehicles could be scruitised in ‘real-world’ driving conditions.
In contrast, the testing of cars is carried out in arguably more favourable conditions in labs using what the group calls “carefully prepared prototype vehicles” supplied by manufacturers.
Changes to the European testing cycle are due to begin in September, with cars also carrying the mobile testing units when driving on real roads for homologation, however Pete Mock, managing director of ICCT in Europe said these changes may not have the desired effect.
“Manufacturers will still be allowed to carefully select special prototype cars for emissions testing. Instead, it would be much better to measure the emissions of ordinary mass-production vehicles, obtained from customers who have had been driving them in an ordinary way,” he said.
Mock added that such a system is already used in the US, and said the European Commission is due to discuss the possible use of testing privately-owned cars by third-parties, despite resistance from manufacturers.
