Fines from motorists who were snapped in camera-controlled bus and tram lanes and gates in Sheffield produced a surplus of £155,000 for the council last year, according to the latest figures.
All money was ploughed back into public transport, as required by law, says a council report.
A breakdown of the costs and income is being provided amid accusations - not only in Sheffield - that penalty charges are used to bolster the coffers of financially beleaguered local authorities.
Most of the money goes on setting up and operating restrictions that are designed to help smooth the flow of public transport, says the report. Fines are £60, or £30 if paid within 14 days.
Surpluses have helped to finance measures such as new road signs and lines, footpaths, railing and road refuges and highway surfaces and drains.
Sheffield drivers paid £688,000 last year against council spending of £533,000. The £155,000 surplus compares with £146,000 in the previous year.