The feeling of being stuck behind a slow farm implement like a tractor, combine or harvester is something that people who live in big cities just don't know. And you have likely passed them hundreds of times. But passing them might have broken the law.
Driving and finding a 'Road Closed' sign is almost always an aggravation. Now that means a detour, perhaps lengthy, to get where you're going. But there likely a good reason for the road to be closed, and quite a bit of trouble ahead if you attempt to circumvent the closure.