Stock car race at the finish line.

Jon Feingersh/The Image Bank/­Getty Images

­Imagine soaring down the road in your Chevy Impala SS, or maybe your Toyota Camry, leaning heavy into the turns. You've drowned the needle in the red, nearing 200 mph now -- as fast as these cars go. Then, zoom, zoom, zoom! A ­metallic flash, then another, then one you can barely even see glides by before a fold of black and white drops just ahead. This is stock car racing, and you've just been lapped at the final flag.

Since the 1930s, stock car racing has cruised into fans' hearts worldwide, as the biggest spectator sport in the U.S. [source: Appalachian State University]. Every circuit, small-town track and league has its own rules, meaning there is no one-size-fits-all answer regarding stock car racing rules. This article focuses on NASCAR, as it's the most recognized name in stock car racing. There are other large leagues, like the Sports Car Club of America or the Champ Car series, that work under similar but different rules [source: Seattle Sports Commission].

­Founded in December of 1947 by Bill France Sr. as a means of unifying racing rules, the National Association for Stock Car Auto Racing launched in Daytona Florida two months before its first officially sanctioned race took place on Daytona's beach course, forever setting the pace for racing history [source: NASCAR]. Today, NASCAR rules govern the top national series: The Sprint Cup, the Nationwide and the Craftsman Truck Series, all of which are held nationwide. No matter the location for these races, the winner, or the fan turnout, one thing remains the same: With fast speeds and human lives on the line, the need for safety and rules remains.

To make sure fans get what they want and drivers get out alive, NASCAR has implemented certain safety requirements, penalties and flags to alert the drivers and crew chiefs to changing conditions and other issues. To win a race, and accumulate the points needed to qualify and move on, racing teams have to follow these rules and know their flags.

Read on to learn how to decipher stock car racing flags.