Use Sunscreen – Even in Your Car
Car windows block only UVB rays. You also need to block UVA rays – the kind that can cause skin cancer, age spots, and wrinkles. UVA rays can easily pass through side and rear car windows. Front windshields are not as much of a concern since they have a plastic interleaf to prevent shattering that absorbs most UVA rays.
You'll need to plan ahead. Keeping sunscreen handy in the car might seem like a good idea, but storing it in the extreme temperatures of the car could breakdown the ingredients, reducing the effectiveness so put on sunscreen before your car ride.
Don't forget about the kids!
Children are especially vulnerable because they usually sit in the back seat, where there is less UVA protection.
If your family is heading out for one last summer car trip before school starts, make sure you and your passengers apply a sunscreen of at least SPF 15 that blocks both UVA and UVB rays.
Check this American Academy of Dermatology link for answers to commonly asked questions about sunscreen and sun protection.