Striking Southern California port truckers who accuse shipping companies of wage theft took their grievances on Friday to City Hall in Los Angeles, where they gained new political backing for their cause. The City Council voted unanimously in favor of a resolution voicing support for the truckers and calling on the companies doing business at the city-owned Port of Los Angeles to abide by federal and state labor laws. The truckers also delivered a petition bearing 27,000 signatures from members of the pubic to Mayor Eric Garcetti's office urging him to weigh in on the drivers' behalf. Scores of drivers have been on strike this week against four freight-hauling companies they say are denying them fair pay by refusing to recognize the truckers as full-fledged employees and illegally misclassifying them instead as independent contractors. The strikes, idling just a fraction of the 13,000-plus trucks hauling cargo in and out of the Los Angeles and Long Beach harbor complex, have caused little if any disruption to the ports or the region's commercial supply chain. But the outcome of the long-simmering dispute has implications for hundreds of companies and thousands of truckers serving the twin ports, which together handle 40 percent of the all container cargo entering the United States. Many drivers earn less than minimum wage after seeing truck-leasing charges and other expenses deducted from their paychecks, costing a typical worker $60,000 or more a year, according to the Teamsters union, which is seeking to organize them. The U.S. Labor Department cites misclassification as a widespread practice that cheats workers out of tens of millions of dollars annually while costing state and federal governments considerable tax revenues. Misclassification is prevalent in such job sectors as janitorial services, home healthcare, construction and e-commerce, labor experts say, but is especially rampant in the trucking industry. Over 65 percent of all 75,000 U.S. port truckers are misclassified as independent contractors, according to a 2014 study by the labor-backed National Employment Law Project. That study put quantifiable costs of misclassification - taxes losses plus wage violations - at $1.4 billion annually. The Teamsters have rallied to the drivers' cause, winning labor contracts for 500 truckers at several Los Angeles-area shipping companies and helping workers file hundreds of wage theft claims. State labor officials have so far awarded truckers $12 million in back wages and penalties from all claims decided so far, the union says.