Deer may be worse in the US because of what's around our roads
Correct me if I'm wrong, but where kangaroos are hopping in front of your car there are generally no ditches on the side of the road. Is there generally vegetation up close to the road or is there a 'buffer zone' where you'd be able to see kangaroos? The lack of ditches and especially if there's a buffer zone, it would provide autonomous cars a fighting chance to see them out there before they get on the road. It might not be possible to predict their movements, but the car can at least slow down to give itself more ability to evade the kangaroo or stop completely if necessary.
Where I live roads outside of cities/towns typically have ditches on both sides, and often tall weeds in those ditches and farm fields or pastures to the other side of the ditch. After June when the corn is taller than a human, the deer can go from invisible to leaping into the path of your car in one second, which is why deer carcasses (or the dried blood from its aftermath before it has rained) are so common. Hopefully heat sensing cameras would be able to see them even if they are 5-10 feet deep in the cornfield, giving the car much better notice than us meatbags get with our pathetic visible light only eyes.
Kangaroos look like they're probably a little heavier and therefore do more damage to the vehicle and its occupants than the typical deer (at least the white tailed deer around here) so I can see why those collisions are probably a bigger issue from that standpoint. Up north they hit moose which can exceed half a ton, the occupants of a car/SUV often do not survive. Luckily they're slower and don't leap about like deer and kangaroos.