 Complete the following phrase:  There is a notable exception to this rule. If there is an incident during the final lap behind the leaders, and the run to the finish line is clear for the leaders, NASCAR may delay the caution until the checkered flag is shown, allowing the leaders to race for the win. In such cases track safety workers may arrive at the scene of the incident. This exception was used at the 2007 Daytona 500 during a last lap wreck in the tri-oval, the 2009 Aarons 499 when Carl Edwards went airborne into the catch fence off Ryan Newmans hood and came to a rest in the middle of the track as cars skirted to either side to cross the line, the 