Cannabis and Driving: A Guide for UK Consumers

Driving after smoking cannabis in the UK or in any country is illegal. As it can cause severe accidents. As cannabinoids impair your motor skills, they may increase the danger to the people inside the car or walking on the road.

It is illegal to drive on a UK road under the influence of any drug. In the UK, it is a punishable offence to drive under the influence of drugs. Or, you have an illegal drug in your blood to some degree.

In the UK, it is illegal to drive with cannabis above the legal driving limit in your system. THC can impair driving for several hours or longer, and there is no guaranteed safe timeframe. Even prescribed medical cannabis users can be charged if they are impaired while driving.

As per Section 5A of the Road Traffic Act 1988, it is illegal to drive or attempt to drive a car if you are under the influence of a controlled drug. In case of cannabis consumption and driving, your blood should not contain more than 2 micrograms of THC per litre of your blood.

What Does UK Law Say About Cannabis and Driving?

Cannabis and driving can be a deadly combination. That is why the UK has strict laws to regulate its usage. You might be convicted of impaired driving if cannabis is found in your system above the specified limit.

Legal Status Overview

Under the Misuse of Drugs Act 1971, the usage of cannabis is controlled in the UK, and it is classified as a Class B controlled drug. Besides, there is the Road Traffic Act that makes it illegal to drive a car or be in charge of one while under the influence of any controlled drug.

The UK law allows the police to do a roadside drug test if they suspect that the driver is driving under the influence.

The police are permitted to do a roadside oral saliva test to check if there is any presence of cannabis in your saliva. In case the test result comes positive, it might lead to an arrest, and a blood sample will be taken for further assessment.

Cannabis Driving Limit in the UK

The cannabis driving limit in your blood should not be over 2 micrograms per litre of blood. The level is set to be extremely low, and a ‘zero-tolerance’ approach is maintained in such cases.

If you compare the levels of cannabis and alcohol in your system, that may lead to legal actions; cannabis is set at a significantly lower level. Even if you have inhaled cannabis in a low quantity, or you have used medical cannabis a few hours ago, you can still be convicted for it.

Table 1: UK Cannabis and Alcohol Driving Limits

How Cannabis Affects Driving Ability

Cannabis can have a significant negative impact on your driving skills and ability. For example, it can slow down your reaction time and make it harder for you to drive under the influence. Besides, the cannabinoid THC, present in cannabis, will reduce the reaction time when driving. This happens because THC binds to the brain receptors that manage motor skills. So, a lack of control over your motor skills may lead to accidents.

It will also cause an impairment of your judgement. So, you will find it difficult to make quick decisions, like applying the brakes or maintaining the car in the same lane when driving. As a result, driving after consuming cannabis may increase the risk of crashing your car and endangering people’s lives.

This is why the UK laws have put a driving limit for cannabis and made it safe for all people on the street.

Cannabis Drive Limit & Police Testing in the UK

As you already know that if THC is found to be more than 2 micrograms per litre of your blood, then you might face a conviction. So, the UK police can do the required tests to identify if you are under the influence of cannabis and driving a car.

Roadside saliva test is one of the primary tests that the UK police are permitted to do if they suspect someone of driving under the influence. A swab is used to take a sample of oral fluids and identify if there is any sign of cannabis in the sample.

Field Impairment Tests are also another way to determine if the driver is in a normal condition to drive the car. Through this test, the driver needs to perform a test of balance and coordination. The police can ask you to walk in a straight line and also ask you to stand on one leg.

If the initial tests come back positive, an immediate conviction and further blood test might follow.

Can You Drive on Medical Cannabis in the UK?

In the UK, you may legally drive under medical cannabis if you are not impaired.

Medical cannabis has been legalised since 2018, and specialist doctors can prescribe cannabis-based medications to patients to treat certain conditions. However, the cannabis level is set to be very low as per the law.

When You Can Still Be Charged

However, even with medical cannabis, you can be charged if the police believe that you are driving with drug-induced impairment, and the roadside test comes back positive. Besides, if you have been driving dangerously with evident signs of poor coordination, slowed reaction time, and poor thinking.

Stay Informed, Stay Safe, Stay Legal

In conclusion, safety should be paramount when you are driving a car on the street. Your and other people’s safety cannot be compromised due to your impaired driving. You may enjoy a puff or two of cannabis when you are in your house. Or, you can be under medical cannabis for your betterment, but you are advised not to drive under the influence.