[cyberferret]

Having had plenty of wallabies (smaller version of Kangaroos) jump out in front of me at dawn/dusk, I concur.

The hopping movement makes it incredibly difficult to judge their speed and direction. They actually cover horizontal space at a far greater clip than they seem to, and also means they can make snap changes in their direction of travel VERY quickly, making any avoidance manoeuvre a bit of a wild guess.

[danieltillett]

They are extremely unpredictable in their change in direction and they will often get panicked by the sound of the car and jump in front rather than away from the car like most other animals.

Unpredictable motion is ideal for evading upright preditors with spears, but no so good for collision avoidance with fast moving metal objects.

[jfries]

Put in another way, unpredictable motion is good for avoiding what's trying to hit you. Not good for avoiding what's trying to miss you.

[mamon]

So, when kangaroo jumps in front of your car your best chance to avoid hit would be to try to steer your car towards it and let kangaroo's instinct do the rest? :)