But what about while sitting in the car? Dermatologists in the United States have noticed that patients often present with more sun damage on the left side of their face than on the right. Studies have shown that UVA radiation is breaching car windows and affecting drivers. While the windshield blocks both UVA and UVB rays, cars’ side windows only block UVB radiation. Sun shining through a window glass can, over time, lead to momentous sun damage. The exposure that clients receive while driving a car can really add up.
Clients can protect themselves by applying broad-
spectrum sunscreen with SPF to their face, arms, neck, legs, and hands, 30 minutes before driving. They should also
make sure that their sunscreen contains ingredients that block UVA rays. As always, clients should wear protective clothing and ultraviolet hindering sunglasses. Hats should be worn especially by male clients with thinning hair and by clients that have a sunroof or convertibles. Clients can also tint windows or apply ultraviolet-protection film in order to limit the amount of ultraviolet rays invading the vehicle.

References:
Butler, S.T., (2011). Sun Hazards In Your Car, Skin Cancer Foundation Journal, 29: 36-37.