Dyfed-Powis Police tested 1,600 fewer motorists in summertime breath tests.
But its targetted approach based on intelligence gathering resulted in a rise to 5.9% positive results of the 4,600 done, about half the number administered in 2016, while Gwent Police found 39% were positive.
Transport is Europe’s biggest polluter, says an environmental group.
But its not only road vehicles which push up emissions as aircraft and shipping are also big contributors with 27% emissions up for transport overall, says Transport & Environment.
VW plans to invest about £20.35 Billion over five years in its main car brand.
The expenditure is intended to boost its development and manufacturing of electric models after the ‘dieselgate’ emissions scandal.
Meanwhile Toyota says it’s working on a new generation of batteries which will have quicker charging and longer range than current technology.
It says this move will be a big step but it’s still five years away from introduction.
In America, Ford has been told it must quicken recall of about three million vehicles suspected to have faulty Takata airbags.
The car maker wanted to delay recall until it had carried out further tests, but the US car safety authority has rejected its delay.