"All diesel cars tested break emissions limits when driven on road"

UK inquiry after Volkswagen scandal finds much higher nitrogen oxide levels than when vehicles are tested in laboratory



All diesel vehicles tested by the government in the wake of the Volkswagen emissions scandal fail to meet EU standards for nitrogen oxide pollution when driven in the real world, with some emitting up to 12 times more than the limits.

A Department for Transport (DfT) study, launched after it was revealed VW had used technology to allegedly cheat emissions tests, found no other company deliberately tried to rig laboratory trials.

However it found a huge difference between the laboratory results and the amount of nitrogen oxide produced when driven normally on the road.

Of 19 new models tested which meet the latest Euro 6 limit of producing no more than 80mg/km of the emission in lab tests, none could reproduce this on the road. The average was nearer to 500mg/km, with some cars getting close to 1,100mg/km.

The study also revealed that none of the 37 top-selling vehicles that were claimed to have met the previous Euro 5 limit – of 180 mg/km – actually stayed within that legal level when driven in the road.

Cars meeting Euro 5 standards – which could be sold up to September last year – were all found to be “substantially higher” in real-world conditions than the measurements recorded in the laboratory.

The report found big variations depending on outside temperatures, with engines producing more emissions when it was cold.

Manufacturers told the DfT that devices to reduce emissions called exhaust gas recirculation tended to switch off when it was cold to protect the engine. This partly explained the lower lab emission readings as these were taken at temperatures of about 20C.

The junior transport minister Robert Goodwill, introducing the report, denied that this meant the lab tests were a farce, but called the results “disappointing”. None of the cars broke regulations as the only current stipulation was to pass the lab test, he said.

The motor industry has been pulling a fast one for years. Lab tests are not representative of road use and never have been. - All the engine auxiliaries are usually disconnected to lighten the load on the engine.