Safety in the Sun
If windows or sunroofs are open then being in a car does not protect either a driver or passengers from getting sunburnt.
If you or your passengers are driving in the sun then you should still apply all the advice listed above. Use sunscreen, long sleeved clothing, a hat and wear sunglasses.
NOTE: You can get sunburnt on a cloudy day. 80-85% of solar ultraviolet radiation can pass through cloud. Haze in the atmosphere can even increase your ultraviolet radiation exposure