Road hogs and tailgaters

Intrigued by a report in today's Straits Times, I googled "road hog"to find out what it actually referred to. Three possible meanings popped up:

"A motorist whose vehicle overlaps the traffic lane used by another motorist."

"a selfish or aggressive driver"

"a driver who obstructs others"

Clearly there isn't much of a consensus here, and the derogatory term could just as well refer to the tailgating speedster on the fast lane or to the guy who refuses to speed while on the fast lane of the expressway. Both have a right to be there, but the tailgating speedster is more likely to be breaking the law. The guy who is keeping to the speed limit is really not breaking the law; after all, where can he drive if he keeps at the speed limit? The middle lane is really going too slow. It seems unreasonable to expect that he should be the one who bears the burden and risk of continually changing in and out of the fast lane so that Bob (see above) can have his religious experience.