Some MetroAccess drivers worked more than 18 hours on Thanksgiving, just a week after Metro told its board of directors that it planned to crack down on long hours that lead to dangerous levels of worker fatigue. The van drivers, who shuttle around riders with disabilities for Metro’s federally mandated paratransit service, are scheduled to work 13-hour shifts, which include a one-hour break. But the work stretched far longer on the holiday as staffing stretched thin.