Drug driving legislation has recently experienced its most substantial overhaul. In March 2015, the new criminal offence of drug driving came into effect and the police have seen increased arrests under the new guidelines and law in the intervening time.

Prior to the new classification, drug driving was classified as an offence under Section 5A of the Road Traffic Act, which states that it is illegal to operate a vehicle whilst being unfit to do so. This law required a degree of interpretation, so the new offence was made in an attempt to clarify the law, introducing legal limits on prescription drugs and illegal drugs.

The offence of drug driving is now much more similar in protocol to the criminal offence of drink driving and the penalties are equally as severe.

UK drug driving law

The law states that it is illegal to operate a mechanically propelled vehicle whilst an individual is impaired by drugs or alcohol.

Once the offence of drug driving was classified in March 2015, clear definitions of impairment in the form of exact thresholds for drug concentrations allowable per litre of blood were introduced. These thresholds exist for both prescription and illegal drugs. Evidence of physical impairment by a police officer is not required any longer as the impairment is assumed by the actual measurement of drugs found in the system.

The allowable concentrations for illegal drugs are very low but there is an allowance for a degree of ‘accidental exposure’, such as where passive smoking may develop a presence in the blood stream.

Prescription drugs have higher allowable concentrations, but these thresholds can be ignored if a doctor has provided confirmation that an individual is fit to drive whilst taking the prescribed medication.

Drug limits

The new offence of drug driving  introduced thresholds for 8 legal drugs (all of which are available under prescription) and 8 illegal drugs. This list will expand to include more drugs as time passes. There are already plans to include drugs included in medication for ADHD and Parkinson’s disease.

The following drugs are available under prescription and have fairly high concentration allowances, but it is legal to drive whilst above the thresholds in a doctor has deemed you fit enough to drive:

  • Morphine – 80 µg/L ( microgrammes per litre of blood)
  • Lorazepam – 100 µg/L
  • Diazepam – 550 µg/L
  • Oxazepam – 300 µg/L
  • Clonazepam – 50 µg/L
  • Temazepam – 1,000 µg/L
  • Flunitrazepam – 300 µg/L
  • Methadone – 500 µg/L

The following substances are illegal and have much lower concentration thresholds, although they take into account the possibility of accidental exposure:

  • Cannabis – 2 µg/L
  • Cocaine – 10 µg/L
  • Ecstasy (MDMA) – 10 µg/L
  • Heroin – 5 µg/L
  • Ketamine – 10 µg/L
  • LSD – 1 µg/L
  • Methylamphetamine – 10 µg/L

Unlike alcohol consumption, there is no unit system to help consumers measure the amount of drugs in their system. This is partly because there are too many factors that could affect the rate of metabolism, including the physical size of an individual.

Drug driving procedure

Drug driving as an offence is more clearly defined than ever before now police roadside procedures and testing are similar to the processes of drink driving.

Swab tests are simple tests that swab saliva in the mouth to detect the presence of cocaine or cannabis. However, these tests do not serve as an accurate measurement against the new legal thresholds and a positive test will almost always be followed be a blood or urine test at the police station to get more accurate measurements that can be relied upon in court.

Field Impairment tests (FITs) are still often used at the roadside to check for impairments that would affect an individual’s ability to drive. These tests can include a simply finger to nose test to assess judgement and coordination, or include pupillary tests to check for evidence of drug taking through symptoms affecting the individual’s eyes.

It is a criminal offence to refuse a drug test without reasonable excuse. If a police officer suspects that you are unfit to drive, you will be arrested and taken to an appropriate police station to provide blood and/or urine samples. These samples will then be reviewed by toxicologists to gain more accurate readings and this evidence will be used in court proceedings.

What are the penalties for drug driving?

If you are accused of the criminal offence of drug driving, you should seek specialist legal advice as soon as you are able to do so. Even with the clarified laws, there are often effective lines of defence or points of mitigation which can lessen the punishment considered for a drug driving offence.

Get in touch with our team of expert motoring offence solicitors at Lawtons for expert advice and assistance.

Nb. This guide is intended to give general information only and not intended to be used as the basis upon which advice is given, nor should it be relied upon as giving advice specific to a case or individual. Lawtons do not accept liability for anyone using this guide. Should you require specific advice in connection with a real case or situation, please contact us immediately so that we can provide specific advice.