Interesting, how would that affect the answer? No, it is a real bus, like the ones they use for humans in public transport. Interesting, if you're curious because aliens might be a different size, no, it is a bus for human-sized things. No. Nope. No, they are normal golf balls. Maybe, after we estimate the number, perhaps we can estimate the time-to-fill based on various rates of child-miscreant golf-ball theft. etc.