SAN DIEGO -- A $1 billion expansion project at Lindbergh Field to double the size of Terminal 2 is now under way.

Known as "The Green Build," it is the largest project in the history of San Diego's international airport.

At last count, more than 18 million passengers have traveled through Lindbergh Field. By the year 2030, it is projected there will be almost double that amount.

The project will create a mirror image of Terminal 2 and will include:

10 new jet gates and passenger waiting areas

a "smart curb" that allows passengers to check in, print boarding passes and check in baggage before walking in the door

a dual-level roadway that will separate arriving and departing passengers

12 security lanes -- double from the 6 currently in use -- to move passengers through the airport faster

expanded concession area for more shopping and dining

But the major expansion will come with some passenger traffic and airport congestion. Travelers who park at Terminal 2 will now have to allow extra time to navigate their way in and around the airport.

The project is expected to create about 1,000 at its peak construction period, and the expansion is also being built with the environment in mind.

If there are no unforeseen project delays, the project should be completed by 2013.