A prison bus caught fire early Friday afternoon in San Leandro, slowing traffic on eastbound Interstate 580.
Prisoners were on the bus when it caught fire on the freeway near 150th St., around 1 p.m., according to the California Highway Patrol.
Fire crews were able to extinguish the flames and prisoners were transported to another vehicle.
There was no cause given for the fire.
Traffic was moving slowly in one lane past the incident as a huge backup built up behind the fire.