Police have launched a summer crackdown on the "menace" of drink and drug driving.
Forces around the country will step up checks and patrols in the month-long blitz, which has seen hundreds of motorists arrested in previous years.
The campaign, which went live on Thursday, targets those who get behind the wheel when over the alcohol limit or under the influence of drugs.
Under laws introduced in 2015, legal driving limits were laid down for 17 prescription and illegal drugs.
There is virtually zero tolerance for drivers apprehended with substances such as heroin, cocaine and cannabis in their system.
Almost 50,000 vehicles were stopped between June 10 and July 10 in a summer clampdown last year, with 45,000 breath tests carried out.
Of those, 4,539, or a 10th, were found to be positive, refused, meaning the driver would not give a specimen of breath, or failed, meaning a specimen is given, but it is not sufficient to determine a result.
The latest initiative will see forces run local operations by focusing on known hotspots and conducting roadside stop checks.
Deputy Chief Constable Garry Forsyth, of the National Police Chiefs' Council roads policing portfolio, said: "In this day and age it is unacceptable that there are still far too many people who risk their lives and the lives of others by driving while under the influence of alcohol.
"Official figures show that on average every year, more than 54,000 people are convicted of driving or attempting to drive while over the legal alcohol limit.
"This year's summer operation will focus on tackling that threat with targeted enforcement that is led by intelligence and presents a strong deterrent against drink-driving."
Drivers were warned they may still be over the drink driving limit the day after consuming alcohol.
Inspector Keith Kellett, of Merseyside Police, said: "Alcohol can remain in your system for many hours and you may still be over the limit the following day.
"Remember, drinks poured at home tend to be larger and there is no one calling 'last orders'.
"If you are driving the following day, leaving it 12 hours before getting behind the wheel is advisable."
West Midlands police and crime commissioner David Jamieson said he supported his force's summer crackdown.
"People driving under the influence of drink or drugs are a menace on our roads, causing harm and misery," he said.