They happen at all hours, but alcohol involvement in crashes peaks at night and is higher on weekends than on weekdays. Among passenger vehicle drivers who were fatally injured between 9 pm and 6 am in 2007, 60 percent had BACs at or above 0.08 percent compared with 20 percent during other hours. Forty-seven percent of all fatally injured drivers on weekends (6 pm Friday to 6 am Monday) in 2007 had BACs at or above 0.08 percent. At other times the proportion was 26 percent.