A Brisbane magistrate has reserved his decision in the case of a police officer who pulled a gun on a couple for speeding along an outback Queensland highway in May last year.

Senior Constable Stephen Flanagan was charged with assault and deprivation of liberty after the couple lodged a complaint over the ordeal.

Flanagan's own dash-cam recorded most of the incident, where he is seen honking at the driver, before getting out of the car and pointing his pistol while swearing at the couple.

He is then filmed handcuffing the driver on the side of the highway, before issuing him with a speeding ticket.

The summary trial began on Tuesday and heard from three witnesses including Flanagan, driver Lee Povey and his partner Anna Lisa Cruse.

'Put you f***ing hands in the air'

Mr Povey told the court he was confused at why a police car was following him without any lights and sirens.

He said when he eventually pulled over, he saw the police officer walking towards his vehicle window pointing a pistol and swearing.

"First up, he said, 'Put your f***ing hands up in the air,'" Mr Povey said.

Mr Povey said he could feel the gun being pushed into his back while he was being handcuffed outside the car, a claim Flanagan told the court was unlikely.

Several videos of the incident were tendered to the court, including Flanagan's dash-cam and a recording Ms Cruse made on her smartphone.

Officer not a rogue lunatic: defence

In his final submissions, Flanagan's defence lawyer Stephen Zillman said the officer thought the car was stolen and the driver may have had a firearm, so he acted quickly.

"From what we've seen and heard on video, it's clear, he was very, very, highly stressed," he said.

"It's not the case of some rogue lunatic police officer simply pulling pistols out, pulling them at someone who's been speeding."

The matter has been adjourned until December 7 and Flanagan's bail has been extended.