A five-day strike by truck drivers at trucking companies’ headquarters, truck yards and at terminals at the ports of Los Angeles and Long Beach is over after drivers returned to work Friday.

Drivers picketed Monday through early Friday morning primarily at the trucking companies’ headquarters and truck yards but also at port terminals, trying to pressure the companies to hire drivers as employees rather than treating them as independent contractors.

The trucking companies targeted were Intermodal Bridge Transport Inc., Pacific 9 Transportation, Harbor Rail Transport and Pacer Cartage, a division of XPO Logistics Inc.

The strike was organized by Teamsters-affiliated group Justice for Port Truck Drivers, which argues that drivers are already employees but are improperly classified as contractors. Labor groups billed the strike as a success, saying it resulted in some cargo for national retailers being left at port docks because terminals turned away trucks from companies targeted by the strike.

But port officials said the action had little impact on operations at the harbor. Phillip Sanfield, director of media relations with the Port of Los Angeles, said the four trucking companies targeted represent a relatively small amount of trucks: about 475 out of the more than 13,000 registered to do business within the port. As a result, Sanfield said, “Cargo flowed through the Port of Los Angeles this week with minimal disruption.”

Lee Peterson, head of media relations with the Port of Long Beach, said the picketed terminals operated throughout the week with no delays to cargo activity, and the port received no reports of cargo backups.

The National Retail Federation also said the strike minimally impacted port and terminal operations, but that continued labor actions make Southern California an unattractive destination for cargo.

“Episodes like this will continue to keep cargo that was diverted from returning to the West Coast ports,” said Vice President Jonathan Gold. “Shippers and retailers need predictability and reliability in their supply chains. Without that they will look for alternate gateways to ship their products,” he added.