A rollover accident involving two semi-trucks took place on eastbound Interstate-40 west of Flagstaff early Sunday morning. DPS says the accident happened at around 4:52 a.m. at milepost 178 in Parks. Both drivers were taken to Flagstaff Medical Center for non-life threatening injuries. The interstate was never closed, according to ADOT. The accident was cleared and traffic returned to normal about three hours later.