Another thing i just remembered since i rode in the rain yesterday. I use the back brake to gauge how slick the road is. Obviously i do this in a strait line. Normally as i'm approaching a light i use more rear then front at first and try to make the back slide just a little to find the traction limit. This is not something you SHOULD do, but it's something i like to do so i have a good estimate of the traction i have on that particular section of road , in case something should happen.