People who live in Baton Rouge, Louisiana, love to complain about traffic, but they have a right to complain about Interstate 110 with its truly epic traffic engineering blunders that make every drive along it a dance with death. The goal was to correct the most obvious blunders and reduce traffic accidents along the stretch of 110 that passes through the city. A Department of Transportation manager examining weekly accident reports prepared by Baton Rouge law enforcement would be using which of the accepted methods for tracking progress toward goal achievement?