Discription of Events: Large 18-wheeler type truck with over size load sign attached to the back(empty at time of incident). Traveling up Highway 21 from 190, without looking or caring merged into my lane while I was next to the truck, nearly hit me, had to slam on the brakes and swerve to avoid being hit. Almost had a head-on collision with a vehicle waiting in a turning lane. Truck proceeded up the road traveling 60+ mph and tailgating.