Carrum Downs police conducted a random breath test as part of Operation Probe this morning.
A 41-year-old driver was pulled over at an RBT site on Frankston-Dandenong Road about 11.30am.
The Cranbourne West man, who was driving with his 8-year-old son, returned an evidentiary breath test of 0.238.
His licence was immediately suspended for 12 months and his vehicle has been impounded for 30 days at a cost of $1040.
He will also be charged on summons with drink driving related matters.