Two cars have been spotted illegally driving on the Luton-Dunstable guided busway.
They were seen on separate occasions, including at 5.30pm on Sunday.
Driving a car on the busway is an offence under article 34 of the Luton Dunstable Translink Order 2006 and motorists can be fined £1000.
Steven Manfredi said: “I saw a car driving down the mighty busway last night, not sure if they were lost or sightseeing.”
CCTV cameras cover all busway junctions with the highway and a Luton Borough Council spokesperson said it is impossible to “accidentally” drive a car on the £91m busway.
Cllr Dave Taylor, portfolio holder for transportation and road safety, said: “There is no excuse for any car or van to travel on the busway. It was specifically designed for buses only and anyone who drives their own vehicle on it is foolish, irresponsible and risks facing the consequences.”
The council spokesperson said: “It is impossible to ‘accidentally’ drive a car on the busway: the only way to do so is to ignore the warning signs and drive across the car traps in some way, risking serious damage to your vehicle.
“Anyone breaking the law in this way risks legal action resulting in a criminal record and a fine of up to £1000.”
The busway opened on September 24 this year and the council estimates more than 120,000 journeys were made on the
four core services from October 1 - 31.