Gridlock relief for morning commuters along the westbound Interstate 580 corridor between Livermore and Dublin is coming in the form of a long-awaited carpool lane.

The Alameda County Transportation Commission plans to begin construction on a high-occupancy/express lane on Interstate 580 that will stretch nearly 13 miles from Greenville Road in Livermore to the Foothill-San Ramon Road overcrossing in Dublin.

Construction on the $182 million-dollar project is scheduled to begin in August and be completed in mid-2015.

"(I-580) is one of the worst congestion corridors in the Bay Area, with 40 percent of the all congestion in the Bay Area going through Alameda County and this corridor," said Art Dao, executive director of the Alameda County Transportation Commission. "You will see benefits of congestion relief almost immediately from the new lane."

Besides a reduction in commute time, Dao said the unseen benefits include fewer cars on the road, which will let trucks that use the corridor get to and from the Central Valley to Oakland more freely.

Eastbound commuters -- who have benefited from an 11-mile carpool lane from Hacienda Drive to Greenville since 2009 -- will see the lane transformed into a combination carpool-toll lane. Carpoolers will still be able to use the lane but, depending on congestion, solo drivers will have access to cruise in it for a fee.

The cost to add the technology for the lane, which was $15 million to build, is $19 million, and it will open at the same time the westbound lane debuts.

"It reduces commutes for everyone," said Dublin Mayor Tim Sbranti, who also sits on the commission's board, about the benefits of the eastbound carpool lane.

"I have seen the improvements myself, and we all benefit from a smoother flow of traffic."

At a time when the commission is preparing to build the new lane and improve the existing one, BART is also moving forward with long-talked-about plans to bring the rail system to Livermore.

If the route continues down I-580 from Pleasanton and Dublin, it would requiring shifting all lanes of traffic to accommodate the system.

Dao said that if or when BART is extended to Livermore, the freeway median is not adequate to house the tracks and would need to be widened regardless of the carpool lanes. He also said the lanes are a good use of taxpayer money because the lanes provide immediate relief for traffic congestion.

"The carpool lanes don't preclude BART-to-Livermore," Dao said. "But the corridor needs immediate congestion relief, and that is what the carpool lanes can do."

Contact Robert Jordan at 925-847-2184. Follow him at Twitter.com/robjordan127.