You say this is full size, but it's only 1024 px high, which suggests it has been reduced in size. Do you still have the full-size original? I always keep my unedited originals as back-up - didgital storage is cheap enough nowadays. If the original is 3000 px or more, that sign might be readable.
I spend a lot of time digging around on ebay trying to find interesting things, one thing I like to do is comb through the huge photo archives for sale on there, always looking for anything interesting of unexpected. Yesterday I was looking for photos from New York’s 42nd Street and found this interesting picture:
At first look I assumed that the bloke lying on the floor had been blown over by what looks like the extreme weather conditions, everyone else in the photo is battling the wind and rain and it looks like 42nd street is in the middle of a full-blown storm. So him being bowled over by the brutal wind made sense, but that’s not what actually happened… Luckily for us the photo seller had also put up the reverse of the photo which gives us a breakdown of what had actually happened just seconds before it was taken: