One person was killed and another seriously injured in a wrong way semi-trailer accident last night northbound on I-29 north of Platte City. Missouri State Patrol says the accident happened just after 9:00. The semi crossed the median and struck the car heading north on I-29. The 66 year old passenger of the car, Cynthia J Humphrey of St Joseph died at Mosaic Life Care from her injuries and 67 year old Herbert D Humphrey of St Joseph was taken to Mosaic Life Care with serious injuries. The driver of the semi-trailer, 71 year old Carl Doty, JR of Missouri Valley, Iowa was not injured.