We have been well-schooled on the alcohol limits and how alcohol affects our driving, but less so on driving under the influence of drugs. In March 2013 the Department for Transport published new research that demonstrates the effect drugs have on driving. You can read the report here. This gave more weight to its plans to introduce a new drug driving offence, and with consultation from various industry stakeholders the government has proposed limits for eight general prescription drugs and eight recreational drugs.
The new rules means that if you drive over the generally prescribed limit for any of them then you are committing an offence which could be punished by a fine, loss of licence or, in certain circumstances, a jail term.
The government has not indicated the exact limits yet, but has said that some or all of them will be above zero to allow for trace effects caused by drugs taken for medical conditions, or if a person accidentally ingests a small amount of an illicit drug (for example LSD or cocaine). Prescription drugs such as temazepam, morphine, methadone and diazepam will also be regulated. The limits on amphetamine will be reconsidered so that patients taking ADHD medication are not affected.
Current alcohol limits
The alcohol limits are not changing and currently stand at:
35 microgrammes of alcohol in 100 millilitres of breath, or 80 milligrammes of alcohol per 100 millilitres of blood, or 107 milligrammes of alcohol per 100 millilitres of urine.
There is no fool-proof way of drinking and staying under the limit as it depends on a number of factors such as your weight, gender, metabolism, current stress levels, how much you have eaten recently, age and any medication you are taking. It takes roughly one hour for the body to break down one unit of alcohol.