A driver slammed into the back of a disabled 18-wheeler Sunday in a fatal crash in northern Montgomery County, tying up southbound traffic on Interstate 45. The wreck happened just before 8 p.m. on I-45, north of Conroe and just south of the Walker County line, according to the Texas Department of Public Safety. A suthbound sedan drove into the back of the truck’s flatbed trailer. The trailer was parked on the shoulder of the road with safety flares marking its location. North Montgomery County firefighters cut the driver out of the vehicle; the driver was taken to the hospital and pronounced dead.