Where? I've never seen any. I've heard that Italy has rules for it but I've never seen any signs in the UK, Scandinavia, northern Germany, Netherlands, Belgium

Where? I've never seen any. I've heard that Italy has rules for it but I've never seen any signs in the UK, Scandinavia, northern Germany, Netherlands, Belgium, or France. I don't even know what it would look like. Looks like I should brush up before this summer's road trip.