If your skin is going to be exposed by the sun’s UV rays for any amount of time, it’s always a good idea to stay protected. And unfortunately, most vehicles do not provide the protection necessary.
While windshields themselves are actually quite good at blocking UV rays–impeding about 100% of UVB rays and 98% of UVA rays–side and rearview windows cannot say the same, with some only blocking less than half of UV rays.
This means that, wherever you are sitting in a car, you are constantly exposed to a solid amount of UV rays, likely from the side. If you’re the driver during a long road trip, this can be particularly treacherous.
To solve the issue, simply apply a liberal amount of sunscreen to your exposed skin, and consider keeping a spare bottle in the car, just in case!