Previously the police could only charge a driver on the basis that their driving was impaired because of a drug. In order to secure a conviction at court, they had to prove not only that the driver had a controlled drug in their system but also that the individual was impaired to drive as a consequence of that drug. They would adduce evidence on the physical condition of the driver and any bad driving, poor performance in field impairment tests and blood results demonstrating presence of the drug. They would also have to show that a police doctor had found that the impaired condition of the driver may be due to a drug. As you can imagine, there are many avenues to defend against this charge and we have found the acquittal rate to be high.
The new law introduced a list of drugs (some prescription and some illegal) that have a prescribed limit for drivers. All the police have to prove now is that you were driving and show that one of those drugs was in your blood at a level above the prescribed limit. Indeed, it would appear that the new law has been successful in achieving higher conviction rates and targeting drug drivers.
The Road Safety Minister has welcomed statistics that suggest that Cheshire police have arrested 8 times as many suspected drug drivers than before the law came into force and that once charged, 98% have been convicted. It has also been noted that 50% of the drivers who have been tested for drugs during a national campaign last Christmas have been positive, a figure that the police believe demonstrates how successfully they have been targeting suspects. In all, 931 motorists out of 1,888 tested during the campaign showed positive results.
There are defences available if you are charged with drug driving over the prescribed limit and the police and police forensic scientists have to ensure that they follow the appropriate procedures. Errors on their behalf can be fatal to the prosecution case.