New research is claiming drivers have been "stung" with millions of pounds in fines after being caught out by sudden drops in speed on British motorways.Confused.com says that since the first variable speed cameras were installed on motorways in 2013, motorists have been left with up to £526 million in fines, with 210,538 drivers have been caught exceeding the limit.It suggests the issue is the way speeds can drop from 70mph to speeds of just 20mph and in a statement says the number of fines are likely to rise even further, with more variable speed zones planned across the UK as part of the smart motorway scheme.Last month it was reported 13,000 motorists have been caught in just six months since variable speed cameras were installed on the M4 between J25 and J28 at Newport and now Freedom of Information data obtained by the website company suggests variable cameras on other stretches of motorway have also accounted for high volumes of speeding tickets. Cameras on the stretch of the M4 between J19 and J20 in both directions have collected40,320 penalty notices between 2015 and 2016, more than any other variable speed camera point in the UK. This is followed by cameras on the M5 between J16 (Almondsbury) and J17 (Easter Compton) with 27,398 penalty notices and cameras on the M1 J10 and J11 at Luton with 21,751 penalty notices.It also says 210,538 UK drivers have been caught speeding by variable 'smart' motorway cameras since 2013(2), each facing fines of up to £2,500, while one in three motorists (32%) have had an accident or near miss caused by sudden drops in speed limits, or know someone who has.Other findings are 78% of drivers caught speeding blame sudden changes in speed caused by variable smart motorway cameras and just one in 10 of motorists are aware variable speed cameras can drop to 20mph on UK motorways.The phrasing of the report suggests that the industry has a way to go to get its message over that variable speed limits are a safety feature and also a way of keeping the traffic flowing better.