But Darren Wright ignored the advice - and was soon stopped by officers.
It emerged that he was three-and-a-half times the drug-drive limit, which has led to a 36-month driving ban.
Prosecutor Micaila Williams told Peterborough Magistrates’ Court on Monday that police had been tipped off about the smokers.
“Officers could smell cannabis. They told Mr Wright not to drive the van behind him.
“However, shortly thereafter officers see the same van that they have warned Mr Wright not to drive.”
Wright, of Stumpacre, North Bretton, was at the wheel of the Renault Trafic when it was pulled over in Ledbury Road. He failed a drug wipe and was arrested.
In custody he gave a reading of seven micrograms of a cannabis metabolite per litre of blood in his system; the legal limit being two.
In interview, he admitted smoking a joint in the field but “stupidly” moved the van because he needed to get materials off it.
The court was told that Wright had two convictions for drink-driving. The most recent, in 2012, meant that he was liable to a mandatory minimum three-year ban for two similar offences in a ten-year period.
In mitigation, solicitor Damian Willats said the defendant realised how “stupid” he had been to try and move the van the short distance.
Mr Willats said recently started his own roofing business but it would struggle to survive with the inevitable disqualification. The court was also told that eight people were dependant on Wright at home.
“Since this happened he had been engaging with Inspire (drug and alcohol support service) to deal with his drug problem,” added the solicitor.
As well as the ban, Wright was fined £120 and told to pay £85 costs and £34 victim surcharge.