Here is my armchair diagnosis: right before the car veers towards the barrier it drives through a stretch of road where the only visible lane marker is on the left. Then the right lane marker comes into view at about the point where the lane starts to widen out for the lane split. The lines that will become the right and left lane markers of the split left and right lanes respectively are right next to the van in fro…
I totally agree with your analysis. What is more worrying is that even following the rest of the traffic would have solved the problem. If you are the only car doing something then there is a good chance you are doing something wrong. Also: the lane markings are confusing but GPS and inertial readings should have clearly indicated that that is not a lane. If two systems give conflicting data some kind of alarm should…
Aside from GPS’ accuracy as mentioned in other replies, also take into account the navigation’s map material. The individual lans are probably not individually tracked on the map, but a single track per road with meta data specifying the number of lanes amongst other featerus. So even if GPS would have provided very accurate position readings, the map source material might not even match that level of detail.