South Australian drivers will be given a three-month “educational period” as new mobile phone detection cameras are officially switched on.

Over a three-month testing phase, SAPOL said it made 71,044 detections from 6,794,050 vehicles — which it equated to 1.05 per cent of motorists using mobile phones behind the wheel.

A driver steering with one finger while holding a mobile phone in one hand and a drink in the other.(Supplied: SA Police)

Under the grace period which will run from June 19 to September 18, drivers detected on the cameras will receive a warning letter instead of a fine or lost demerit points.

From September 19, offending drivers will face an expiation notice of $540, plus a $99 victims of crime levy and three demerit points.

Officer in Charge of SAPOL Traffic Support Branch Superintendent Darren Fielke said the grace period only applied to offences detected by the new cameras.

“People caught by police illegally using their mobile devices when driving will still be required to pay a fine,” Superintendent Fielke said.

“We have seen, from other jurisdictions, a significant change in behaviour of people not using their mobile phones after the introduction of mobile phone detection cameras so, by introducing these cameras to high-risk areas, we hope this will contribute to improving driver behaviour.”

Police said recent changes to the Australian Road Rules had broadened the definition of using a mobile phone to include circumstances where a mobile phone was being held, including in a driver’s lap.

Mobile phone detection cameras in Adelaide have caught more than 71,000 drivers doing the wrong thing.  (Supplied: SA Police)

The law exempts drivers using their phones to make a payment while the vehicle is stationary in a road-related area.

“Using a mobile phone while driving increases a driver’s crash risk by at least four times,” Superintendent Fielke said.

“The risk increases in high-volume traffic areas, where inattention and distraction contribute to a greater number of collisions.”

Cameras are in place at five “high-risk locations” — South Road at Torrensville, the North-South Motorway at Regency Park, Port Wakefield Road at Gepps Cross, the Southern Expressway at Darlington and Port Road at Hindmarsh.

Two more undisclosed locations are now being considered with cameras to be installed early next year.

One of the mobile phone detection cameras on South Road at Torrensville.(Bobby Macumber, ABC)

All new cameras will be marked with signage.

“Using a mobile phone while driving increases a driver’s crash risk by at least four times,” Superintendent Fielke said.

“The risk increases in high-volume traffic areas, where inattention and distraction contribute to a greater number of collisions.”

Police said computer artificial intelligence would be used to process images and identify drivers using mobile phones illegally.

The images will be reviewed by “unsworn adjudicators who have specific training”.

The crackdown is part of SA Police’s aim at reducing road trauma caused by driver distraction.