The number of UK drivers attending retraining courses after committing a motoring offence reached a record 1.4 million last year, new figures show.
Speed awareness courses were by far the most common with 1.2 million attendees, according to analysis of data from the National Driver Offender Retraining Scheme (NDORS).
The money police forces receive from each driver who completes these courses jumped from £35 to £45 in September, meaning constabularies collect around £54 million each year.
This is designated as a cost recovery fee to reimburse forces for the expense of catching speeding motorists.
Steve Gooding, director of motoring research charity the RAC Foundation, said: "What might perplex drivers is how the number of offenders sent on speed awareness courses differs hugely by constabulary.
"In 2016, 80,235 drivers were offered the courses in Avon and Somerset. In neighbouring Wiltshire, nobody was."
The total number of attendees for all nine retraining courses available rose by 2% year-on-year.
Mr Gooding believes this "could be topped" in 2018 as police step up enforcement of red X signals on smart motorways.
These motorways use the hard shoulder for traffic unless it is closed, normally because of an accident or broken-down vehicle.
Around 80,000 warning letters have been sent to drivers who have broken smart motorway rules since December 2016, with around a third relating to driving in closed lanes.
Government-owned company Highways England expects police forces to begin taking action this spring against drivers caught on camera ignoring red X signals, which could lead to a spike in the number sent on motorway awareness courses.
NDORS courses are provided by private companies on behalf of the police.
They are offered to drivers at the discretion of forces and attendance means offenders will avoid penalty points on their licence and a fine.
There are huge differences in what drivers can expect to pay depending on where they live.
NDORS said in October that speeding motorists attending courses in Northamptonshire pay £75, while those in Essex will pay 32% more (£99).