Aaron Ben Ellis, 24, who was living in Northway, Fulstow, at the time of the incident, admitted the offence when he appeared at Boston Magistrates’ Court last week.
The court was told that Ellis was stopped in his Ford Transit at 12.45am on November 23, 2018, on the A16 at East Keal and admitted to police that he had ‘a spliff before driving’.
Prosecutor Nick Todd said the reading was 4.5 microgrammes, more than twice the legal limit of 2.
Michelle Elvin, mitigating, said Ellis had a bad year with a number of relations and friends dying.
She said he admitted to smoking cannabis at a friend’s house before setting off on a planned overnight drive to a re-enactment event.
Ellis, now living in Springway Crescent, Grimsby, was banned from driving for a year and ordered to pay £350 and £115 in costs and charges.