Bus lanes across Sheffield are raking in nearly £5,700 a day in fines, it can be revealed.
Two bus lanes in the city generated more than £200,000 each last year, nine made at least £100,000 and all 16 between them earned Sheffield Council close to £1.5m.
The huge sums have prompted calls for a review of signs and road markings, which campaigners believe may be confusing drivers.
Peter Sephton, chairman of Sheffield City Centre Residents Action Group (SCRAGG) said: "It seems clear from the fact that Sheffield has so many bus lane fines being generated that we have a problem.
"It could be that local drivers are less law abiding. Or it could be that failing to make bus lane signs clearer for motorists causes confusion that generates more income.
"The purpose of a bus lane is not to generate income; it is to divert traffic to other routes so that public transport can run reliably on-time with minimal traffic delays.
"These figures suggest there needs to be a review of all the high-fines bus lane signs in Sheffield to see how they can be made easier to understand."
Sheffield Council said bus lanes were clearly signposted and all income from fines was ploughed back into public transport, cycling and walking schemes.
The biggest earner in Sheffield is the bus lane in London Road, at the junction with Asline Road, outside Lowfield Primary School.
It has generated £1,138,000 since January 2013, with more than 31 fines a day being issued on average, and it pulled in £211,000 during the last financial year, 2015/16.
Traders and residents close to the junction were unsurprisingly wise to the bus lane, but they said it often caught out visitors.
John Gosling, who runs the Hearth and Home Fireplace Centre with his dad Pete, said countless delivery drivers had been caught out.
He believed the signs in place were clear enough but said some sat-nav systems still directed drivers down the bus lane.
"Personally I don't know why the bus lane's there. It doesn't reduce traffic at all and it seems slightly pointless having it for just that stretch of road," he added.
James Broomhead, branch manager at the Bathroom and Tile Showroom, said: "It's easy if you're not from this neck of the town to get caught, and we've had lots of customers getting fines."
He added that he believed many of those fined were probably looking for parking spots, which are at a premium in the area, so may not have been giving the signs their full attention.
He also branded the road layout across Sheffield 'rubbish', claiming it was too geared towards bus drivers and taxis at the expense of ordinary drivers.
Manoj Athi, a partner at Athi Law Solicitors, said he felt the London Road bus lane was well signposted as were most others across the city.
He said the lane had always been access only and there might be a lot more congestion along London Road were it open to all traffic.
Hat Elmi, who lives a stone's throw from the bus lane, said many friends and family visiting her - especially those coming from other cities - had been fined.
"I think it could be better signposted. The road markings should be clearer," she added.
The tally of fines came from Freedom of Information requests sent by the BBC to local authorities across the country operating bus lane cameras.
Five Sheffield bus lanes featured in the top 100 nationally for the sum being generated per day, with the London Road lane placed 28th.
A bus lane in Newcastle, which generated 251 fines each day, making just shy of £6,000 in the process, topped the list.
Motoring organisation the RAC told the BBC bus lane cameras were becoming a new 'cash bonanza' for councils and the amount being raised was 'frightening'.
The figures do not tell the full story when it comes to Sheffield, as some bus lanes have only recently been enforced by cameras or had their layout or restrictions changed.
For example, the bus lane in Boston Street, close to St Mary's Gate, generated £131,000 in just over seven months between mid April and late November last year - equivalent to around £215,000 over the course of a full year.
The Star last month highlighted how hundreds of drivers had been caught out by recent changes to the bus and tram lane on Glossop Road in Sheffield city centre. They were sent warning letters rather than being fined during a bedding-in period.
SCCRAG has complained to the council about the signs in place, which it claims are misleading, but says its calls for changes have so far gone unheeded.
A Sheffield Council spokesperson said: "We are confident that the signs, which have been in place at Glossop Road for six years, meet government regulations and importantly are clear to motorists.
"We are talking to the residents' group about their concerns and would like to reassure motorists that when we carry out enforcement such as this we provide at least a two-month warning period to help drivers get used to any changes.
"Any camera enforcement income is invested back into public transport, cycling and walking schemes.
"The responsibility for not driving in bus lanes or through bus gates ultimately rests with individual drivers."
The fine for driving in a bus lane in Sheffield is £60, with a £30 discount for early payment.
* Income generated during 2015/16: £1,480,384
* Fines issued during 2015/16: 44,827
* Average sum per day (since enforcement began): £5,693.96
* London Road bus lane has made £1.1m since January 2013
* Five Sheffield bus lanes in top 100 nationally for income generated since enforcement began
* Average generated per year per bus lane is £92,524
Which Sheffield bus lanes are generating the most in fines?
Location//total income from fines*//average income per day*//income during 2015/16//number of fines issued during 2015/16
London Road/Asline Road: £1,137,963//£807.07//£211,455/ /6,419
Middlewood Road: N/A//N/A//£208,946//5,825
Moore Street: £558,530//£688.69//£171,446// 5,217
Langsett Road: N/A//N/A//£151,834//3,965
Boston Street: £131,310//£588.83//0//0
Glossop Road: N/A//N/A//£130,960//3,342
Broad Street: £494,862//£532.11//£122,053// 3,181
Mansfield Road: £201,767//£313.30//£111,404// 2,894
South Lane: £264,982//£283.10//£76,214//4, 198
Granville Street: £230,880//£126.93//£50,536//1, 613
Queens Road: N/A//N/A//£22,344//881
Bridge Street: N/A//N/A//£19,263//826
Holme Lane: N/A//N/A//£18,173//492
Bolsover Street: £159,078//£112.82//£427//10
Ecclesall Road: £9,540//£80.85//0//0
* since enforcement began