Flagstaff Fire crews were busy on I-40 Tuesday morning after a semi-truck rolled over at the Walnut Canyon Exit east of Flagstaff. Crews arrived at around 4:30 a.m. where the truck left the highway and overturned, blocking the exit. The driver was able to get out of the cab under his own power, but he was taken to Flagstaff Medical Center with non-life threatening injuries. Crews worked to contain leaking diesel fuel from the truck preventing it from contaminating the area. It’s unknown what caused the truck to leave the road, but driver fatigue may have contributed to the accident.