Above: Oh, that Mr Pumpy, what a card!
You'll see a lot of broken down trucks along the way, along with everything else.
Highway 5 just before Sisophon. This is a good section of road. Note the landscape: dry and barren.
Note that Highway 5 runs east from Poipet, becoming Highway 6 at Sisophon and continuing on to Siem Reap. You don't need to worry about this, as it's effectively the same road.
Highway 5 actually turns south and heads to Battambang.