NOGALES, Ariz. — Construction of the expanded Mariposa Port of Entry is progressing on schedule, port officials say.

Groundbreaking for the revamped border crossing was in October 2009, and after a year of construction, the first of four phases was nearing completion, said Eloy Cortez, assistant port director for trade, U.S. Customs and Border Protection.

Phase one included filling in existing 80-foot canyons, installing retaining walls, building drainage systems and laying the electrical lines and all of the infrastructure needed to operate the facility as well as completing a pedestrian walkway.

Perhaps the best news, aside from the fact that the project is on time, is that the construction has not impeded the flow of traffic, Cortez said.

If all goes according to plan, that will continue to be the case.

In fact, four additional truck lanes should be opened even before the project is completed, which could speed up the border-crossing process.

When finished in late 2013 or early 2014, the facility will have 56 offloading inspection docks, eight commercial lanes and 12 lanes for passenger cars.

Funding for the project, which is expected to cost up to $220 million, will come largely from economic stimulus funds.

Phase two will include bringing in temporary facilities that will house Customs and Border Protection personnel until the new quarters are completed, building out eight cargo lanes — double the current number — and building a temporary dock that will accommodate 26 trucks at once.

Phase three will be the demolition of the existing buildings.

Phase four will be the build-out and move-in phase.