Two best friends and former cop victims of deadly Brisbane tunnel crash

Two best friends from interstate and a former police officer have been identified as the victims of a double fatal Brisbane tunnel crash.

Emma McLean, a 23-year-old from South Australia, and Lily Galbraith, a 24-year-old from the Northern Territory, are believed to have been on their way to a wedding when they entered the Legacy Way Tunnel at Mount Coot-tha yesterday afternoon.

The silver Mazda they were driving was struck by a black Audi, which caused them to crash into a small truck.

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Galbraith, believed to be a nurse working at Flinders Private Hospital in Adelaide, was killed in the crash.

McLean, who was engaged and planning her own wedding, was left fighting for her life in hospital after undergoing surgery overnight.

The driver of the Audi, 56-year-old former police officer Bruce Daley, was also killed.

Daley served as an acting senior sergeant and it is unclear when or why he left the force.

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Brisbane Lord Mayor Adrian Scrhinner paid his respects.

"I just want to say to those people and families that have been impacted by this tragedy, the hearts of everyone in Brisbane are going out to you," he said.

Detective Acting Inspector Chris Hansel said the crash was a "tragedy".

"Every life lost on our roads is a tragedy and we continue to implore drivers to practice patience," he said at a press conference today.

Hansel said police have obtained footage from inside the tunnel and are investigating all vehicles involved.

"Speed is obviously being considered as a contributing factor," he said.

Witnesses reported online that they saw the Audi driving at more than 200km/h.

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Hansel said the crash was confronting for first responders, who worked on scene for hours before the tunnel reopened.

"It's confronting personally, it's confronting professionally," he said.

Queensland's road toll has risen to 99 lives lost this year, sparking warnings to motorists across the state ahead of the long weekend.

"Be vigilant, be patient, be aware of your surroundings," Hansel said.

"With the long weekend coming up, we will have a lot of traffic on our roads."

Anyone with information or dash cam footage is urged to contact Crime Stoppers on 1800 333 000.