Authorities are in pursuit of the driver of a suspected stolen big rig Wednesday morning. Sky5 is overhead.

The pursuit of a semi truck without a trailer was started by the Fontana Police Department, the California Highway Patrol told KTLA.

When Sky5 arrived on scene, the truck had made its way to Orange County, traveling on surface streets in Fullerton.

In Buena Park, the truck briefly stopped on Commonwealth Avenue.

As officers exited their vehicles for a possible standoff, however, the truck took off again.

It appears two people are inside the vehicle, though the passenger has tried to exit the vehicle and was prevented from doing so by the driver, said Officer Steven Reed of the Fontana PD.

The driver of the big rig, which police believe is stolen and has license plates that don’t match the vehicle, is refusing to let another man get out, that passenger’s daughter told police.

The nature of the relationship between driver and passenger has not yet been disclosed.

Police have tried to stop the pursuit, with a SWAT vehicle purposefully colliding with the big rig just before 11 a.m. That attempt was unsuccessful.

Nancy Fontan and Nidia Becerra contributed to this report. Check back for updates to this developing story.