Two people were also injured in the multivehicle wreck that shut down Interstate 35 for seven hours.
The crash occurred at about 11:55 a.m. in the northbound lanes at the Elm Creek bridge near FM 1306, where bridge maintenance had narrowed the two lanes to one.
DPS Trooper Mark Tackett said an 18-wheeler driver by James Crayton, of Dallas, apparently did not slow before it hit the first vehicle. The car exploded on impact, killing Anthony and Kimberly Brandon, of Bedford.
Crayton's truck then slammed into a Honda Accord driven by Carol Whaley, 63, of Yalaha, Fla., injuring him and his wife, Linda, 61.
The 18-wheeler then hit another vehicle, ramming it into the rear of another 18-wheeler. The driver of that vehicle, Darryl Hoosier, 55, of Lafayette, La., was killed.
The driver of the second truck was not injured.
Carol Whaley is listed in fair condition at a Fort Worth hospital. His wife was treated at a Gainesville hospital and released.
Crayton, 59, suffered minor injuries and was transported to a hospital for testing and questioning.
The truck he was driving is registered to Bradco Supply.