I've never even heard of a 'bus gate' before. Don't have those kind of things out here in the middle of nowhere.
I presume that there is signage telling drivings that there is a bus gate ahead - way before they actually find themselves confronted with it. But from that link it doesn't seem to be the case. In fact why are cars even allowed onto that road initially if it's not a through route. Seems ridiculous to me, just another damn money making scam.