Tinted car windows drew the attention of the police and resulted in the driver being banned.
Blackburn Magistrates' Court heard when police spoke to Michael Zackiewicz they suspected he was under the influence of something.
He passed a breathalyser test but failed a drugs wipe and was arrested.
Zackiewicz, 36, of Openshaw Drive, Blackburn, pleaded guilty to driving while over the limit for cocaine and its derivative, benzoylecgonine.
He was fined £120 with £85 costs and a £48 victim surcharge and banned from driving for 12 months.
Imran Hussain, mitigating, said his client believed the drugs he had taken the day before would be out of his system.
"He is very remorseful," added Mr Hussain.
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