Police said they saw a black Mitsubishi Evolution and a white Nissan Skyline travelling next to each other at at excessive speed about 12.05am on Sunday. They were driving southbound on Canberra Avenue. Police suspect the drivers were travelling at 140km/h in an 80km/h zone.

Both drivers were stopped at Hindmarsh Drive, Symonston, and their vehicles were seized.

Officer in Charge of road policing, Detective acting Inspector Ivan Naspe, said the incident was a poor end to National Road Safety week.

"The message remains everyday and police are focused on keeping our roads safe for all road users," he said.

Police conducted 677 breath tests and seven drivers were found drink driving over the weekend.

"While seven positive readings from close to seven hundred tests may sound like a low number, it's still seven too many," Detective acting Inspector Naspe said.

"One of these drivers returned a blood alcohol reading of .114 - to be out on public roads driving in such a state is not only irresponsible, but also reprehensibly dangerous."

Police also fined 92 speeding drivers, seven unregistered drivers, two drivers disobeying a stop sign, three uninsured drivers, a driver not displaying P plates and a driver who was using a mobile phone.