7/13/17 A USPS big-rig flipped over early Thursday and prompted the closure of northbound State Route 29 just north of Tower Road near American Canyon, according to California Highway Patrol officials.
According to CHP officials, who issued a Sig-alert, the crash was reported at 4:29 a.m.
The big-rig is a United State Postal Service trailer that spilled mail all over the lanes when it overturned, according to CHP officials. Officers were working to get the truck in an upright position. Even when they did, though, traffic was backed up for miles.
UPDATE: Northbound Highway 29 in Napa County is closed as crews work to get #USPS trailer in upright position. https://t.co/ToRpsYtEAH pic.twitter.com/ObQgG0dXTE
— NBC Bay Area (@nbcbayarea) July 13, 2017
Source: Overturned USPS Mail Carrier Causes Traffic Nightmare on Northbound State Route 29 | NBC Bay Area