As spring spreads across the nation, bikers are popping up as regularly as the lilacs, magnolias and daffodils. Biking among adults has undergone somewhat of a renaissance in America, according to various transportation studies. And why not? Biking is great exercise, easy on the environment and perfect for sightseeing. But any time you mix bikes with motor vehicles, accidents can happen. Before you saddle up for your next ride, you should know the latest on bike safety.