Skin cancer is the most common cancer in the U.S., affecting 1 million people each year. It's also preventable (think wide-brimmed hats, broad-spectrum sunscreen, and indoor playtime during peak sun hours) and 99 percent treatable if caught early, like mine. But here's news: A recent study by researchers at St. Louis University School of Medicine in Missouri suggests that people who spend a lot of time in the driver's seat are more likely to develop skin cancer on their left arms, hands, heads, and necks. And drivers who roll up the windows are not immune. “Windshields tend to be laminated and tinted, so they have more of a filtering effect, while the side windows in most cars are not, which means less protection,” explains lead researcher, Scott W. Fosko, MD, a professor and chairman of the department of dermatology at St. Louis University. Before you get behind the wheel, slather up with a broad-spectrum sunscreen or wear a long-sleeved shirt. And if you're planning a long road trip, consider an aftermarket window treatment or tinting for your car's side windows.