That's not an optical delusion. A week ago there was a big mess on 495-N in Massachusetts–a tanker truck spilled several large containers of red dye onto the road. A week later the road is still red, and the redness continues for several miles up the road. As you can see the far side of the road is also tinged with red.
I have no idea if the dye is permanent, but it's been there for a week now. Here's a news article showing what the road looked like then. I didn't drive on it that day, but I feel bad for the owners of all these cars which must be spattered with the crud. According to the news article, the dye washes off with soap and water.
