SAN DIEGO (FOX 5/KUSI) -- A semi tractor-trailer caught fire under the Interstate 15 bridge at Mercy Road and Scripps Poway Parkway Thursday morning, said California Highway Patrol. The incident occurred around 5:30 a.m. FOX 5/KUSI responded to the scene, with the driver stating that he had pulled over in the Miramar Ranch North area after noticing the semi's check battery light had come on. He exited the cabin and temporarily stepped away from the vehicle to speak with someone. Once the driver returned to the semi tractor-trailer, he noticed that it had become engulfed in flames, prompting him to call for help. Firefighters arrived at the scene to help extinguish the blaze. Around 6:20 a.m., smoke could still be seen pummeling from what appeared to be the engine of the semi tractor-trailer. Both areas of the roadway were closed for the response. Morning commuters should expect delays in the area. This is a developing story. Please check back for updates.