Drivers caught with certain levels of prescription or illegal drugs in their system will soon face similar punishments to those who have been drinking.
Recommended limits for 16 different drugs - eight prescription and eight illicit - have now been approved, meaning that from the autumn, those drivers caught with the drugs in their system should face bans and fines.
The initial level for amphetamine was set at 50mg, but this will now be readdressed following concerns that those who take medicine for attention deficit hyperactivity disorder could be affected.
Other illegal drugs on the list include cannabis, with drivers being classed as 'over the limit' if they are found with more than 2mg in their system. The guideline for cocaine is 10mg and 1mg for LSD.
Prescription drugs included in the new laws include morphine (80mg) and methadone (500mg ).
RAC technical director David Bizley said: "We are now a step closer to the law on driving under the influence of drugs being strengthened by the introduction of specific limits for the more common illegal and legal drugs that impair driving. This is clearly good news for law-abiding motorists.
"Our research has found that motorists, while being tolerant of speeding, are much less forgiving of those who drive regularly, or excessively, under the influence of drink or drugs. Fifty-five per cent of motorists are calling for a lifetime ban for such offences with 95% saying a ban of some duration is needed. However, only 49% of 17-24-year-olds support a lifetime ban for those caught regularly or excessively under the influence of drugs compared to 62% of 45-59-year-olds.
"This attitude again highlights the dangers of allowing people to drive without regular reminders about the dangers of drug driving and how impaired senses can lead to serious injuries and fatalities. It also brings back into focus motorists' concerns that the reduction in visible policing that has occurred as policing budgets are tightened has encouraged offenders to continue to endanger themselves and other road users.
"It is illegal to drive if you're unfit to do so because you are under the influence of drugs - whether legal or illegal. The RAC fully supports the punishment of motorists who 'drug drive' and believes a clear message should go out to those that drive under the influence of drugs that it is completely unacceptable and should not be tolerated."
Road safety minister Robert Goodwill added: "The results of the consultation is sending the strongest possible message that you cannot take illegal drugs and drive.
"This new offence will make our roads safer for everyone by making it easier for the police to tackle those who drive after taking illegal drugs.
"It will also clarify the limits for those who take medication."
Copyright Press Association 2014