A 34-year-old man is in Froedtert Hospital this morning with injuries suffered in a late night vehicle accident in Mount Pleasant.  The driver of the of the pickup truck the man was riding in, a 21-year-old Mount Pleasant man, faces charges of operating a vehicle while under the influence of narcotics and causing great bodily harm, possession of marijuana, possession of drug  paraphernalia  and failing to yield the right of way.   The accident occurred at the intersection of WI-20 and 90th Street in Mount Pleasant around 10:30 PM Monday.   Police officers witnessed the accident.  A white, 2001 Ford pickup truck fail to yield at the intersection as it was turning onto southbound 90th Street.   It   collided with a 2005 Dodge pickup truck which was east bound on Hwy 20.  The force of the collision sent both vehicles into a spin, and the Ford struck a traffic light.  The 34-year-old passenger had to be extricated from the vehicle and then was flow by Flight for Life to Froedtert Hospital in Milwaukee.  The 21-year-old man and the 47-year-old driver of the second vehicle received only minor injuries.   The crash is being investigated by the Wisconsin State Patrol Traffic Reconstruction Investigation Unit and the Mount Pleasant Police Department.