Beltway drivers could be shaving 30 minutes off their commutes thanks to new express lanes, proponents say. And the lanes are set to open as early as December.

Northern Virginia officials showed off the new lanes Wednesday, touting the 495 Express Lanes Project as a panacea for the traffic troubles of the Virginia suburbs.

"We think this is actually going to be a showcase for the rest of the country. [Express] lanes, in our minds, are going to be the way of the future in places like Northern Virginia, where the ability to expand existing roadways is going to be extremely cost-prohibitive and extremely difficult due to geography," said Virginia Secretary of Transportation Sean Connaughton. "[The lanes are] going to make getting around Northern Virginia much easier, much faster, much more predictable."

The four new lanes in the middle of the Beltway will be free for cars with three or more occupants. Others will have to pay a toll, which will rise and fall throughout the day based on how congested the lanes are. Project managers expect the tolls to be about 25 cents per mile at night and as much as $1.25 per mile during rush hour. The lanes won't have toll booths -- all those who pay must have an E-ZPass or risk being caught on camera.

The lanes will stretch from Interstate 95 near Springfield to just north of the Dulles Toll Road, near the Maryland border.

The prospect thrills travel trackers.

"The Beltway in Northern Virginia for years and years has been exhibit A as to why we have the worst congestion in the United States. Think of it -- by the end of this year, that may be no longer true. Hallelujah!" Lon Anderson, director of public and government relations at AAA Mid-Atlantic, said.

The express lanes have been in the works since 2002, and construction began in 2008.

Officials on Wednesday urged Beltway drivers to be cautious as nearly 1,000 construction workers finish off the express lanes during the next several months. Workers will soon remove the concrete barriers separating them from passing cars and replace them with orange barrels, said Tim Steinhilber, general manager of the express lanes project.

"Focusing on eliminating distracted driving is more important than ever," he said.