If your in-car GPS has support for Suna, you can get a fair idea of any lurking traffic threats on your route. If it doesn't but you're an Optus subscriber, you now have another option: a mobile phone traffic alerts service which derives its data from the movements of Optus customers.
The TrafficView service does pretty much what you'd expect: identifies potential traffic snarls, suggests alternative routes and sends SMS alerts for up to 30 "saved journeys" you carry out regularly.
One other big differentiator from Suna-enabled GPS devices: it isn't free. Optus customers can trial it for 14 days, but after that you either need to pay $3.99 for a monthly subscription or 55 cents per alert for occasional alerts. In practice, if your regular commute gets traffic problems more than twice a week, the subscription will be cheaper.
I'm a non-driver so won't be putting this to the test directly; if you try it out, tell us about the accuracy (or otherwise) in the comments.