Whenever there is a new historical landmark discovered, there is always a story that needs to be told.
Scenario #1: A sudden sinkhole blocking traffic, forcing the cars to stop, and be abandoned. (Very King Kong.)
Scenario #2: A sudden attack coming from the front forced people ditched their cars in a rush. Given the estimated time of the end of World War 2, another round up for the Nazi Death Camps is not out of the question. An isolated Air strike in the front could stop the traffic. Then the ground force could round up the people with a few threats, they could even be able to round up people without a shot. which is important since there aren’t any bullet holes.
Scenario 3: The Russians invaded!
Scenario 4: A nearby festival (like an Oktoberfest, or maybe a film festival, [it looks like the parking done at a drive in, or an extremely large party].) and people were rounded up by an army there.
Scenario 5: A giant flood that dried out and made way for the forest, stopping all of the cars from working.
Scenario 6: Brad Pitt filmed “Inglorious Bastards” nearby, and there was a mechanical error.