The drug driving limits and how long drugs stay in your system

On 02 March 2015, it became an offence to drive with certain drugs in your system above specified limits.  The Section 5A Road Traffic Act Offence requires only the presence of the drug above the specified limit to provoke criminal proceedings against you. Under the new offence, it is not necessary for the prosecution to prove that there was anything wrong with your manner of driving; just the presence of the drug above the limit is enough.

What are the drug driving limits?

The drug driving limits have been set with reference to the amount of the drug “per litre of blood”. No drug driving limits have been set for urine; therefore if you cannot provide a sample of blood, you cannot be convicted of driving with drugs in your system over the specified limit.

The drug driving limits per litre of blood for all substances, legal and illegal are as follows:

  • Benzoylecgonine (a cocaine metabolite) 50
  • Clonazepam 50
  • Cocaine 10
  • Delta-9-Tetrahydrocannabinol (cannabis) 2
  • Diazepam 550
  • Flunitrazepam 300
  • Ketamine 20
  • Lorazepam 100
  • Lysergic Acid Diethylamide (LSD) 1
  • Methadone 500
  • Methylamphetamine 10
  • Methylenedioxymethamphetamine (MDMA)10
  • 6-Monoacetylmorphine (Heroin) 5
  • Morphine 80
  • Oxazepam 300
  • Temazepam 1000

It’s important to remember that the above limits are specific to the newer Section 5A Drug Driving Offence, not the old Section 4 Driving whilst Unfit through Drugs Offence which is still in force.

Under the old offence, the driver need only provide a sample of blood or urine which identified the presence of a drug in their system regardless of the amount of the drug, providing there was a causal link between the presence of the drug and the person’s manner of driving.

What do the drug driving limits actually mean?

Many motorists are struggling to work out what the drug drive limits actually mean.

It’s impossible to say with any certainty how much of a drug can be consumed before reaching the specified limits.

However, the drug driving limits for illegal drugs have been set to practically zero tolerance levels. It is said that as little as one puff on a joint could be enough to put you over the limit.

Whilst the drug driving limits are deemed to be zero tolerance limits, they have been set with reference to scientific guidance to allow for accidental consumption such as passive smoking of cannabis.

The drug driving limits for legal drugs have been set above normal therapeutic doses; therefore if the you’ve taken your medication in accordance with usual prescribing instructions then you’re unlikely to be over the limit. If you have been prescribed a dose which is above the specified limit, then a medical defence will be available to you, provided that you have taken the medication in accordance with the prescribing instructions of your medical professional.

How long do illegal drugs stay in your system?

It’s impossible to say with any certainty how long you would need to wait after taking drugs before you’d be deemed under the limit again. There are far too many variables.

The length of time required for a drug to leave your system depends on lots of different factors. These factors include the strength and amount of drug taken, the timeframe during which the consumption of the drug took place, and whether the drug was mixed with anything else. Other unique individual characteristics also play a crucial factor such as your metabolic rate, height, weight and gender.

Although bodily absorption rates differ from person to person, it is possible to suggest rough guidelines as to how long illegal drugs typically remain detectable in a person’s system.

Of the illegal drugs covered by the offence, the typical number of days that traces of a drug will remain in your system for are as follows:

  • Cannabis: 2 – 3 days for one off use (potentially up to two months for chronic users)
  • Cocaine : 12 hours – 3 days
  • MDMA: 1 – 4 days
  • Heroin: 2 – 5 days
  • Ketamine: 2 – 4 days
  • LSD: 1 – 3 days
  • Crystal Meth: 1 – 4 days

However, the above guidelines relate to the length of time that traces of the drug would remain in your system. The guidelines do not necessarily relate to the amount of time that the drug would remain in your system at a level above the specified limit.  With cannabis for example, the specified limit under the offence relates only to the active delta-9 ingredient, which remains detectable in your system for far less time than the cannabis metabolite.

If you’ve taken an illegal drug then it’s best to wait a significant period of time before getting back behind the wheel of a car.

What happens if I’m caught with an illegal drug in my system above the specified limit?

If you provide a blood sample which identifies the presence of one of the controlled drugs above the specified limit, then you will be charged with drug driving and summonsed to attend Court.

The Courts take drug driving offences very seriously, and a conviction would have long lasting consequences. The sentencing guidelines for this offence were recently finalised by the sentencing council, and it could be argued that the sentencing for drug driving has become harsher

If you plead guilty, or if you are found guilty, you would face:

  1. A minimum 12 month disqualification from driving
  2. An unlimited level fine
  3. Possibly up to 6 months in prison or community service
  4. A criminal record
  5. Problems travelling to certain Countries like the USA
  6. The drug driving conviction would appear on your driving licence for 11 years
  7. Significant increases on your motor insurance premiums

A conviction for drug driving could have a serious impact on your future career options. Employers of professional drivers would want to look at your driving record and will see that you have a conviction for drug driving. Certain professional bodies will require you to disclose the conviction, and could stop you from practicing in your field.

Can a drug driving offence be defended?

If you have already been accused of drug driving, then all is not lost. There are many defences to a drug driving allegation. So much so that we have a 100% acquittal rate in defending drug driving offences. If you have been arrested for drug driving and would like to speak to an expert drug driving solicitor, call our free advice line on 0330 33 22 770 for free initial legal advice. Early advice can often make the difference between a successful outcome or not. We are always happy to discuss your case and can often identify potential defences within minutes. Lines are open round the clock so get in touch whenever’s best for you.

Article written by Drug Driving Expert, Alison Ashworth; Managing Director of Ashworth Motoring Law.

Alison Ashworth; Expert motoring lawyer and Director of

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