Drivers caught speeding on a Devon road could have their convictions quashed.
Mobile cameras are used frequently on parts of the A379
Mobile speed cameras often operate on the A379 at Starcross between Exeter and Dawlish.
But four cases have been dismissed because of road sign problems. Those previously convicted may get fines returned and licence points erased.
The Devon and Cornwall Safety Camera Partnership, which runs the cameras, says it is reviewing what action it will take in response to these cases.
Speeds not challenged
Mobile speed cameras have been used frequently in recent years on the busy and narrow stretch of the A379.
But the signs telling drivers of speed limits have been deemed as set too far apart.
A judge involved in the four cases dismissed charges, saying the signage and traffic orders were fatally flawed.
The four drivers were doing up to 44mph (71k/ph) in the 30mph (48k/ph), according to the cameras.
This judgement may result in anyone being found guilty of speeding in the area since June 2002 being able to get their conviction dropped.
This could run into thousands and may include holidaymakers who regularly use the road en-route to Dawlish Warren or Dawlish.
Devon County Council, which is in charge of road signs, said it would wait for a full written judgement before making any comment.
The Safety Camera Partnership pointed out the drivers did not challenge the speeds recorded.
It defended the use of cameras in the area, saying they had helped reduce injuries on this stretch of road to zero between 2003 and 2004.