One in 20 lead-foots get away Low visibility: Drivers escaped fines due to camera faults as well as glare, mud or illegal coverings. Almost one in 20 motorists caught speeding last year escaped a fine because cameras failed to read their number plate properly. The state government missed out on more than $3 million in revenue because fixed digital speed cameras were riddled with flaws, including faulty flashes and out-of-focus images. But thousands of motorists were also let off the hook because their plates were obscured by mud, illegal coverings, incorrect positioning and even inclement weather. Of the 342,479 speeding vehicles captured by fixed digital speed cameras across the state last year, 16,306 were never fined. One-quarter of those lucky motorists were let off because the fixed speed camera took images that were either out of focus, too dark or too light. Another quarter had number plates that were unable to be read because of glare or reflection. Coloured and premium plates introduced by Roads and Maritime Services in recent years also appear to have backfired on authorities with at least 1341 motorists let off last year because the plates - which can be black with dark lettering - were unreadable. A Transport for NSW spokeswoman conceded in some circumstances when the sun is low, images of some plates are affected by glare. "Roads and Maritime Services is updating a number of older technology cameras in order to improve number-plate readability," the spokeswoman said. RMS will only proceed with a penalty where there is no doubt about the correct identification of number plates. The number of people who were photographed speeding but not fined last year increased slightly on 2011, according to the RMS figures obtained by Fairfax Media. Safety cameras, which detect red light and speed offences, were more reliable than fixed cameras, with one in 50 motorists let off because their number plate was indecipherable. There were also some more novel ways motorists escaped a fine. Between 2010 and 2012, 292 motorists were let off the hook because weather affected the fixed camera's image. A further 197 motorists were not fined because it was sunrise or sunset, and dirt or mud obscured another 302 number plates. President of NRMA Motoring and Services Wendy Machin called on the government to make public the results of annual audits and calibration of speed cameras. "The community must have confidence that cameras are placed for genuine road safety hazards and not simply to raise revenue," Ms Machin said. State opposition spokesman for roads Ryan Parkes echoed Ms Machin's call for greater transparency, saying the infrequent and confidential testing of speed cameras gave the public little confidence in their reliability. "For every person that has been let off you've got to then ask some questions about every person who simply accepted the letter in the mail," he said.