Three people are dead after a truck loaded with gravel crossed the median of Interstate-80 and slammed into two oncoming vehicles this morning just east of Des Moines. Highway Patrol Sergeant Rob Hansen says the semi-truck was westbound, went across both lanes, went across the median and struck the eastbound vehicles pretty much head-on. There was one person in each of the three vehicles — all three were killed. Sergeant Hansen says the two smaller vehicles that collided with the on-coming semi were a pickup truck and a Honda S-U-V. He says it appears the those cars tried to get out of the way.Hansen couldn’t say yet if the truck driver might’ve had some sort of health problem that caused him to lose control.The truck dumped its load of gravel. One eastbound lane of I-80 near Altoona is closed. Traffic -is- moving through the area, just very slowly.