[enko]

Not to nitpick, but wombats can actually run pretty fast when they want to - up to 40kph. And I reckon kangaroos, while fast, aren't very manoeuvrable; if they're on a line they tend to stay on that line, right into the path of the vehicle.

Koalas, though, geeze - they're slow, drunk usually, and don't give a damn. I almost hit one once, slamming on the brakes and almost going off the road, and the damn thing didn't react at all, just kept unconcernedly strolling across. Doubt anything can stop them except fences combined with safe crossings (tunnels, wildlife bridges).

[dwd]

Probably makes a wombat even more problematic if they decide to run back across the road. Just make sure the fence has a decent concrete footer - they're pretty unstoppable.