For reasons unknown at this time the big rig flipped on its side as it was traveling westbound on the Lowell Avenue on-ramp to the Foothill (210) freeway at about 2:41 p.m. this afternoon.

“The driver was not injured,” said California Highway Patrol Officer Kimball.

Westbound traffic is slow in the area however all lanes are open. The Lowell on-ramp is expected to be closed until 6:45 p.m. to 7:45 p.m.