Lioness Like Creature

Just thought you might be interested in my cat sighting for ongoing research.
I recently had to drive from Darwin to Brisbane. About 300km from the QLD border on the Barkly Hwy at about 2am I saw what I describe as a lioness looking creature. It startled me as it ran out of the bush towards my car. I hit the brakes and started to slow down from 80km/hr. It continued running beside the car on the passengers side until I reached 40km/hr where it overtook me and ran in front of the car disappearing in the bush on the other side of the road. The animal was in full stride and very much bigger and more muscle bound than a dingo. I drive a small hatchback and would say the animal was easily over 1.5 metres tall and very long, although it was stretched out running. I have driven around the entire country and work in the outback and this is my first strange sighting. I am very familiar with Australian wildlife and the average feral cat.
I hope this helps your big cat project,
If you need more information please contact me,