Arkansas State Police say three people were killed and at least seven were injured in separate chain-reaction crashes on Interstate 49. State police say the first collision happened at about 11:45 p.m. Monday when a tractor-trailer slowed down and was rear-ended. A total of 10 vehicles were involved in this wreck in the southbound lanes of traffic. At about the same time, three tractor-trailers in the northbound lanes collided directly across the median from the southbound crash scene. State police say one of the trucks was carrying glue that spilled onto the highway.