There were more than 900 arrests in a little over two months following the introduction of the new drug driving offence, according to a FOI request by the IAM.
The IAM asked every police force area in England and Wales for the number of arrests made for the new offence since it was introduced on 2 March 2015. The FOI request shows a total of 902 drug-drive arrests.
The IAM says the results show “little consistency” in testing and arrests, with figures ranging from more than 200 in one police force to zero in others.
The Metropolitan Police recorded the highest number of arrests, with 214 in just over two months, which equates to three drivers every day since the law was changed. Northumbria Police have the second highest number of arrests (97) followed by Cheshire Constabulary with 70, Sussex Police with 58 and South Yorkshire Police with 55.
At the opposite end of the scale Leicestershire Police, Warwickshire Police and Gwent Police have yet to make any arrests.
A full list of results from each police force is available on the IAM website.
Sarah Sillars, IAM chief executive officer, said: “I am sure the majority of law abiding drivers would like to know why there is such a variation in the data we have received from police forces. It would be unfortunate if some people got the idea that some areas are softer on drug-driving than others.
“It is very clear from our survey that the new drug driving law has just scratched the surface of a much bigger issue.
“It would seem Sir Peter North has been proved correct when he said there is a significant drug-driving problem which is out of all proportion to the number of accidents reported to the police.
“We have reached a point where drink-driving has become socially unacceptable, particularly among younger people. We now need a sustained campaign to back up the police enforcement effort and ensure drug-driving is seen in exactly the same way.”