To complete one of the Winterfest challenges and earn some XP for your battle pass in Fortnite, you must go to one of the locations where it is possible to find traffic lights.
They are few and you can find them using your map. When you go to the list of challenges, if you click on the start "Decorate traffic lights for the winter party", you can see a map on the right of your screen with the different locations of the traffic lights. They are generally in named places.
We found two in Slappy Shores, northeast of the game map. We recommend starting with these two there as they are closed.
You can find a third light a little further north on your map, at the gas station.