The ports of Los Angeles and Long Beach announced Wednesday that they will extend by 60 days the evaluation period for a controversial program aimed at reducing emissions from the 16,000 short haul trucks serving the port complex.

The ports’ harbor commissioners were set to vote on the Clean Trucks Program in July, but amid a spirited public debate over the program’s merits the ports decided to extend the deadline by two months.

“In the interests of fairness to those who offered their input, we need time to evaluate their suggestions,” said Richard Steinke, executive director of the Port of Long Beach, in a release. “We remain committed to aggressively improving air quality with a Clean Trucks Program, and our aim is to get this right.”

The proposal, part of the ports’ jointly-sponsored Clean Air Action Plan, would retrofit or replace all of the short haul trucks serving the ports with cleaner-burning rigs, which could reduce diesel truck emissions by as much as 80 percent.

The plan would force drivers the vast majority of whom are independent owner operators to become employees of motor carriers, which has drawn criticism from the trucking industry. Carriers contend the plan will drive up costs for trucking companies, because they will have to maintain the trucks and start paying benefits such as health insurance and workman’s compensation.

The California Trucking Association has estimated that the plan could force more than 1,000 of the approximately 1,300 trucking companies serving the ports out of business within the next year.

But the proposal has received strong support from environmentalists, immigrant rights and neighborhood groups and union officials. The disparate interests have come together to form the Coalition for Clean and Safe Ports which has backed the plan.

The coalition on Wednesday arranged for a convoy of about 30 trucks to drive slowly along the Harbor (110) Freeway to show support for efforts to clean up San Pedro Bay’s air.