DEVELOPING: A commercial truck driver named Juan Hernandez-Santos of Huentitlan, Mexico, was arrested at the scene of a 6-car pileup on I-5 in Lacey, WA, on Thurs. The driver was hauling cars & slammed into the back of the school bus after 7:00 am & didn't have a commercial driver’s license, insurance, or a valid medical card. Four people were sent to the hospital with minor injuries. Hernandez-Santos was booked into the Thurston County Jail for a gross misdemeanor charge of operating a commercial vehicle without a valid license.