A crash on Interstate 5 that sparked a grass fire caused a massive traffic backup south of Sacramento on Friday. Two cars and a big-rig crashed about 3:30 p.m., just south of Twin Cities Road, near Galt, according to the California Highway Patrol.The crash sparked a grass fire, which damaged a bridge on I-5, and shut down all lanes for more than an hour.Watch report here: Crash, fire causes massive traffic backup on I-5The shutdown caused a massive backup that at its peak went as far south as Peltier Road in Acampo. Franklin Boulevard also experienced delays as drivers tried to avoid Interstate 5. The two cars and big rig involved in the crash were severely damaged in the fire.Two minors involved were taken to a hospital and treated for minor injuries, a CHP official said.A Caltrans crew was sent to the scene to inspect the bridge for structural damage.After the inspection, the roadway was reopened.The Department of Fish and Wildlife was also notified because some debris from the crash fell into water below the bridge.The cause of the crash remains under investigation.Fire crews also responded to a report of a grass fire on southbound Interstate 5 at Hood Franklin Road. That fire, which was quickly contained, was also sparked by a vehicle crash.