Well, I am a traffic engineer (designing roads, making sure the publi transportation can go on, making policy and more things like that) and I thought this was typical for the Italian Highways. I have used plain Cardstock, a silver gelpen and a ballpointpen.
Does this project or one of it's images contain pornography, profanity, or other illegal or offensive material? If so, please report it and our moderators will come by and clean it up in a flash.