The speed limit on the Beltway Express Lanes in Virginia could rise to 65 mph from 55 mph.

The Virginia Department of Transportation is reviewing a request from the company operating the lanes, Transurban, to raise the speed limit, spokeswoman Joan Morris said.

"We are currently reviewing data to determine if raising the speed limit to 65 mph is safe and can be sustained operationally. A final determination will be made in the next few weeks," said Virginia Secretary of Transportation Sean Connaughton in an email.

Morris said state engineers have conducted a speed study and are still determining whether to change the limit.

"It looks like it should happen, but it's not a done deal," she said.

The speed limit on the regular lanes would remain 55 mph, Morris said, so officials would have to "make sure there's no confusion with people seeing the wrong [speed limit] sign."

Transurban spokesman Mike McGurk said the company has been planning to raise the speed limit but had to wait until the lanes had traffic to do the necessary studies. "Even in the planning phases there was an expectation that the speed limit would eventually be increased to 65 mph, consistent with the current conditions in the [Interstate 95] corridor where HOV speed limits are higher than the regular lanes," he said in an email.

The lanes, which opened late last year and stretch from Springfield to just north of the Dulles Toll Road, promise a congestion-free ride on the Virginia side of the Capital Beltway in exchange for a toll, which varies based on how many cars are in the lanes. Carpoolers and buses can use the lanes for free.

But recent reports show the lanes have struggled to attract drivers and profits. An average of 26,294drivers took the lanes on weekdays from January to March, a report from Transurban showed -- less than half of the 66,000 users a consultant predicted in 2007. And the lanes lost about $11.3 million in their first six weeks of operation, documents presented to investors showed.

Transurban is in the midst of an advertising campaign to convince drivers to try the lanes.

The company opened up the lanes for a free weekend in early April, with the lanes receiving about five times more traffic than on a normal weekend, McGurk said.

McGurk said he could not give figures on whether the recent ads were leading to more people using the lanes because of company rules relating to information shared with investors.

A Transurban spokeswoman earlier said the company spent "several million dollars" on ads for the lanes.

"It's a big change for the region. A lot of people are stuck on autopilot for their commutes," McGurk said. "Once you get out there and you actually experience it and you see that it is predictable, [drivers] do like it."