One person was killed after a head-on collision on Interstate-40 east of Flagstaff Saturday night, due to a car driving on the wrong side of the highway. DPS state troopers were called to the scene on westbound I-40 near Twin Arrows Casino at around 8:46 p.m. Officials say a passenger car was driving eastbound in the westbound lanes when it hit a semi-truck head on. The driver of the car was pronounced dead at the scene. Two people in the semi-truck were uninjured. DPS says impairment is suspected for the driver of the car. I-40 was closed for nearly five hours while crews cleared the scene.