POLICE are investigating a high speed crash in the Graham Farmer Freeway tunnel that occurred just after 12am overnight which may have been a result of drag racing.
Emergency workers were several hundred metres from the entrance in the right-hand west-bound lane attempting to retrieve a duck that had wandered into the tunnel prior to the crash.
The speed limit had been changed to 40 km/h while the emergency workers were in the area, with an emergency alert system notifying drivers on the road.
The driver of a white Mitsubishi Lancer, believed to be speeding, lost control of his car.
Police say the car slammed into the left wall of the tunnel and spun out of control, narrowly missing a car in the centre lane before hitting the crash barrier on a Main Roads truck.
The male driver and female passenger, both in their 20s, were taken to Royal Perth Hospital with serious but non-life threatening injuries.
Police are keen to speak to the driver of a two-door silver Nissan Skyline – possibly a 370Z model or similar – that was also travelling in the tunnel at the time of the crash.
Anyone who witnessed the crash or saw either the Mitsubishi Lancer or the Nissan Skyline before the crash should call Crime Stoppers on 1800 333 000.
Witnesses can also make an anonymous report online.