Orange fluorescent paint on wet pavement, Torrensville, South Australia.
Details: Nikon 50mm 1:1.8D, f/5.6, 1/320s, ISO 200, slight curves, 20% overlay layer with Gaussian blur.
I bet it's from wardriving :)
n3on: Unfortunately nothing so exciting. The local council has made a pass around our neighbourhood, spraying these marks on sections of footpath that have risen too high, and need to be replaced before someone trips and sues them.
However, I did walk around the block about a year ago, with my Pocket PC, counting WiFi access points, and was surprised at the number. Of course most of them were wide open. I should do it again and see if the number has gone up.
Oh well :) but be careful !