This is a photo and article about a road in the states that was died red after:
A tractor trailer carrying dye intended for mulch deposited some of its cargo on the highway after the load shifted.
Apparently the dye was easily washed off of the cars (the local car wash made some good money) and came off of the road pretty quickly too.
I can think of two places in Cape Town where paint spills have marked the road for years. I actually quite like coming around the corner and seeing the paint – it reminds me of good times.