In order to emphasize the yellow-line rule at Daytona International Speedway, where passes are not permitted, NASCAR has made the single yellow line into a double yellow line.
The second yellow line was painted on the inside of the existing yellow line. This change was made more for the fans and less for the drivers, since on a normal highway if it's a double yellow line, it means "do not pass." This way, it will not be so confusing to fans since next week at California drivers can pass below the (single) yellow line.
We all know about the Talladega win by Regan Smith that didn't count because it was said he wasn't forced below the yellow line. NASCAR emphasized NO passing below the double yellow line, or their position will not count and they will be penalized.
Drivers, beware of the yellow line. What is the definition of "forced below the yellow line?"
Just ask Regan Smith.