Wichita ? Federal transportation officials will be in Kansas next week to investigate a string of fatal accidents at a construction zone on U.S. Highway 50 in central Kansas.

Members of the National Transportation Safety Board will also visit Michigan to review similar accidents there, trying to determine if they are looking at a growing national trend, said Mike Crow, director of operations for the Kansas Department of Transportation.

Nine people have died in three separate accidents on U.S. 50 near Peabody in the past three months. All three accidents involved tractor-trailers hitting vehicles that were stopped or driving slowly because of construction.

Kansas Highway Patrol officers said evidence indicated the truck drivers in two accidents in June could have been sleepy. Those accidents occurred on consecutive days at almost the same location.

Since the wrecks, state transportation officials have installed additional warning signs for drivers near the site and have increased patrols in the area.