I've been struck by some of vehicle paths since the Marines Module and latest patch, so I did some experiments. In the tests shown below the road layout is identical, the vehicle was always given a move command, there are no enemy forces, objectives etc and I have tried to put the waypoints at the same place:
In the first column, with no buildings near the junction, the lorry does a sharp left turn at the crossroads.
In the second column, with a building, it doesn't do the sharp left at the crossroads, but does a sharp(ish) left and then sharp right to get back on the road.
In the third column, with a building nearer the crossroads, it doesn't do any sharp turns at all.
When I first saw this in a scenario, my first thought was that it was the turning circle of the
vehicle that caused the behaviour, but the above results suggest that something more is involved. Any ideas?