Nearly 4,000 drivers a day are fined for driving in bus lanes, with one enforcement camera making £6,000 every 24 hours.
The BBC contacted 160 highways authorities in England, of which 64 had bus lane cameras.
According to data released under the Freedom of Information Act, the councils received around £31m between them during 2015-16.
The BBC said the figure is likely to be higher as some councils were unable to break down figures by individual cameras or lanes.
The bus lane camera producing the highest level of fines is on the northbound section of John Dobson Street in Newcastle-upon-Tyne.
Newcastle City Council revealed that between 23 February and 31 October 2016 it generated nearly £1.5m from 62,975 penalty charge notices, equivalent to £5,960 a day.
The BBC said about 5,100 drivers caught in the first two months of the camera's operation were subsequently given refunds after it was found that signs were ‘inadequately lit’ during the hours of darkness.
Newcastle City Council told the BBC that bus lane cameras were not there to make money and the number of fines had dropped ‘dramatically’ over the past year.
RAC spokesman Simon Williams called the Newcastle figure ‘shocking’ and said bus lane cameras are fast becoming a new ‘cash bonanza’ for councils.
He said: ‘Rather than just rubbing their hands together and taking the money councils should be asking questions as to why so many motorists are being caught driving in bus lanes. They should be looking to understand if motorists are deliberately flouting the rules or whether this is happening accidentally, and if so why.'
Mr Williams said the RAC does not believe the majority of motorists drive in bus lanes on purpose, and they are either confused by the signs or have not seen them.