Police have praised motorists who reported a lorry driver four times the limit as he drove on the motorway.
Arturs Barisevs, 35, was spotted driving erratically and swerving all over M11 near Cambridge on the motorway at 4.15pm on 10 October.
Several members of the public called the force control room and said they were worried he would cause a crash.
One said Barisevs seemed to be falling asleep while driving on the M11 northbound, going on to the A14 westbound towards Huntingdon from Cambridge.
Just 22 minutes later, police tracked down the HGV on the A14 westbound, between Godmanchester and Huntingdon, and stopped it in an emergency layby.
When officers asked Barisevs, from Latvia, to step out of the vehicle they noticed he was swaying and his eyes were glazed.
He was asked to give a roadside breath test and gave a reading of 177 microgrammes of alcohol in 100ml of breath.
Barisevs was arrested on suspicion of drink driving and a further sample at the station gave a reading of 140 microgrammes of alcohol in 100ml of breath – four times the legal limit of 35 microgrammes.
He was charged with the offence the following day and appeared at Cambridge Magistrates’ Court on Tuesday where he pleaded guilty and was handed three months and two weeks in prison.
Barisevs was also disqualified from driving for three years.
PC Emma Howard, who investigated, said: “We would like to praise all the members of the public who noticed Barisevs’ manner of driving on Sunday and called us to report their concerns.
“They did exactly the right thing and thanks to those calls, just two days later, Barisevs was not only banned from the roads for a considerable amount of time but is now also behind bars.“