Police spotted David Miller, 30, driving a white van on the M8, heading for Coatbridge, Lanarkshire. But after he returned to West Lothian and stopped in Livingston, officers detained him.
Nearly 1.5kg of the Class A drug – which could be worth up to 59,400 – was recovered from a carrier bag, the High Court in Edinburgh heard.
Miller, a technical courier of Fells Rigg, Livingston, admitted being concerned in the supply of cocaine on 2 April this year at Stonebank in the Ladywell area of Livingston.
He told police that he had travelled to Coatbridge in his works van to collect a package on behalf of someone whom he declined to name.
At first he claimed he did not know what was in the bag, but then stated that he only knew it was cocaine because of the smell, said advocate depute Laura Thomson.
When arrested by police he said: "Not a drug dealer, was not intending to supply drugs."
Sentence was deferred for a background report.