Nearly 20,000 fines have been issued to motorists caught illegally driving in two city centre bus lanes.
Leicester City Council said it had received nearly £450,000 in penalties from the cameras installed in July in Charles Street and Causeway Lane.
Transport bosses said the cameras were put in to prevent buses getting caught in congestion and they hoped the number of drivers caught would tail off as they got the message about enforcement. Mayor Sir Peter Soulsby, who is in charge of the council's transport policy, was "surprised" by the number of fines.
He said: "The purpose of these cameras is to make sure cars don't go into this area.
"My guess is it is very substantially fewer than used to be the case.
"The bus companies have said they are finding it easier to get through.
"If the figures were troubling then we might have to look at improving the signage."
From a peak of just over 6,000 fines in July, the first month, the number fell to 4,365 in August and 4,228 in September before going up again in October, to 4,952. The council has not been able to provide figures for November or December so far.
In the first four months of enforcement, £438,181 was generated for the council in fines. This will rise, as not all the fines have been paid.
Drivers are fined £30 if they pay within 14 days, rising to £90 if they leave it for more 28 days.
One driver, who did not wish to be named but who contacted the Mercury after being fined in Causeway Lane, said: "It's about making money for the council, pure and simple. What else can it be, because it's obviously not stopping drivers going down there?
"It's a stealth tax and anyone who denies it is living in cloud cuckoo land."
However, others said drivers only had themselves to blame.
Ray Pierce, 52, of Kibworth, said: "It isn't like there are no signs. They are there and they are clear to me.
"If anyone is in cloud cuckoo land, it is the drivers who go down there and get all angry when a fine is pushed through their letterbox."
Sir Peter insisted the cameras were put in to change drivers' habits.
He said: "All the money is reused to support transport initiatives, such as free bus travel for pensioners."
The number of fines has prompted a council scrutiny review.
Councillors will consider whether the current set-up – where only buses, hackney cabs and cyclists are allowed in bus lanes – should continue.
It will also consider whether the lanes should be enforced round the clock or just at peak times.
Further enforcement cameras on bus lanes are planned in Rutland Street, in the city centre, and Aylestone Road early this year.
