Fast lane. There is a big hill there and I imagine the vicitms didn’t see the truck until right before impact.
I read an article several years ago that said a person should always drive in the most right-hand lane possible. Drunks driving on freeways will almost always stay in the slow lane. If they are driving the wrong direction on the freeway, that is the fast lane going the other direction.
This is the scenario in ALMOST All wrong way crashes on freeways.
Something to keep in mind.