Sunscreen maker "Oasis Beauty" has suggested putting sunscreen on hands before driving. This is sound advice, coming from a producer of sunscreen. The International Agency for Research on Cancer says drivers should wear gloves, long sleeved shirts and sun glasses. Unless one is a professional driver this is a bit much.
Car producers state that laminated windscreens do block UV radiation: 80 percent of UV-a. It is side windows that are dangerous, though 37 percent of UV-a and 97 percent of UV-b are blocked. From these data obviously the New Zealand Cancer Society and Oasis Beauty are wrong and car glass does offer protection. Furthermore, most countries do allow side windows to be tinted which helps.