While many people might think it's teenagers who are most guilty of texting while driving, USA Today reports that a new study from AT&T found that it's actually adults who text more behind the wheel than teen drivers do. Nearly half of all adults surveyed for the study admitted to texting while driving -- even though 98 percent said they know it's dangerous -- while a lower 43 percent of teens said they do it. AT&T carried out the survey for its It Can Wait campaign, which seeks to educate drivers about the risks of distracted driving. As part of it, they've launched a free app that sends an automated, customizable reply to incoming texts when the vehicle is moving at 25 miles per hour or more. Texting while driving is illegal in 39 states and Washington, D.C.