That does seem to be a lot of cars driving in that specific area while there aren't that many in the background. Also none of them are honking which seems odd.
However, if this was staged you kinda think they'd have chosen better conditions than in the rain.
Cars are all travelling at a uniform, abnormally low speed, in the same lane, and you can hear somebody on a megaphone yell "Cut cut cut!" at the end, so... yeah.