The driver was caught more than twice the legal limit and has lost his licence.
Volunteer Special officers were on patrol in Sawston on 19 May when they spotted Roland Alldashi’s Mercedes going too fast through the village.
They stopped him and he admitted drinking ‘one minute ago’ and having just left a nearby pub.
Alldashi, 46, of Shingay Lane, Sawston, blew 73 microgrammes at the roadside, twice the legal limit of 35 microgrammes per 100 mililitres of breath. In custody he gave an evidential reading of 70.
At Cambridge Magistrates’ Court on 8 June, Alldashi pleaded guilty to drink driving and was disqualified from driving for 18 months and fined £120.
PC Christopher Smits, from the South Cambridgeshire Neighbourhood Policing Team, said: “There are no excuses for drink driving. Alldashi put not only his life in danger but other road users too.”