Motorists took more than 30,000 free trips on the Washington area's newest toll road Wednesday, when the first 7.2-mile stretch of the Intercounty Connector opened to traffic in the pre-dawn darkness.

The number of drivers curious about the six-lane highway - or eager to escape bumper-to-bumper local roads - remained low enough to give it an empty, forgotten feel for much of the day. Open pavement remained plentiful even during the morning rush, when 5,600 vehicles used it between 6 a.m. and 9 a.m.

Eric Letvin of Elkridge said he was surprised more people didn't join him on the first section that opened between Interstate 270 in Gaithersburg and Norbeck Road, one mile east of Georgia Avenue in northern Silver Spring.

"It's so open, you almost feel like you're driving on the moon," said Letvin, an engineer who commutes to the National Institute of Standards and Technology in Gaithersburg.

The empty asphalt made it difficult for many motorists to keep to the posted 55 mph speed limit. The "slow" lane often traveled at 65 mph. Maryland Transportation Authority Police issued citations and written warnings, though the total number wasn't available late yesterday, said Sgt. Jonathan Green. Officers also helped drivers who couldn't find their way off the highway, he said.

By 4 p.m., after being open about 12 hours, the first day's traffic count reached 21,500 - the number of vehicles that Maryland transportation officials said they expect will eventually use that section in a 24-hour period after traffic volumes stabilize.

Traffic will continue to increase over the next three to five years - the typical "ramp-up period" for a new toll road, said Kelly Melhem, a Maryland Transportation Authority spokeswoman.

"As excited as we are to have all these vehicles trying out the road, it's certainly not indicative of what traffic volumes are likely to be over the long term," she said.

The highway's true popularity will be measured over the coming months, particularly after tolls kick in March 7.

The tolls for passenger vehicles on the first stretch - based on some of the highest rates in the United States - will be 60 cents to $1.45 for passenger vehicles, depending on the time of day. Driving the entire 18.8-mile segment will cost passenger vehicles up to $6.15. The rest of the ICC is scheduled to open to Interstate 95 in Prince George's County by early 2012.

State officials have said they will keep the road free-flowing, even if it means raising rates to discourage some motorists.

The ICC is Maryland's first all-electronic toll road, with tolls being charged at highway speeds via vehicles' E-ZPass transponders. Motorists without an E-ZPass will receive a "notice of toll due" in the mail, along with a $3 administrative fee. That fee will be waived until April 6.

Edwin Munoz, a driver for Spectrum Foods, said the ICC cut 10 minutes off the one-hour drive between his company's Landover offices and Gaithersburg, where he delivers meat to restaurants. He said he doesn't know whether his company will pay the tolls.

"Ten minutes is gold for us," Munoz said.

Letvin said he's happy to pay if it shortens his one-hour commute. He said he'll try another route to the ICC on Thursday because he found traffic on westbound Route 198 and Norbeck Road heavier than usual Wednesday when he tried to reach the ICC's temporary eastern terminus.

"I probably lost a good 15 minutes there," Letvin said. "I was a little disappointed."

He said his evening ICC commute cut 10 to 12 minutes off his drive.

Melinda Peters, the ICC construction's project director for the Maryland State Highway Administration, said the morning backups on westbound Norbeck were typical for rush hour. The state will continue to evaluate the ICC's impact on local roads and adjust traffic signals as needed, she said.

"We're seeing traffic flow really well at both ends of the project," Peters said.

The first vehicles traveled on the ICC, which also will be known as Route 200, at 3:30 a.m., officials said.

The first stretch bypasses the hilly, two-lane local roads that many commuters use to travel between jobs near Interstate 270 and suburbs to the east.

The ICC's total construction costs are budgeted to reach $2.56 billion. Its impact is being felt on the sensitive stream valleys it crosses and in neighborhoods where the ICC replaced a swath of woods and took parts of back yards.

"It was different when I walked out here this morning," Brenda Funk said from her back deck in the Brooke Manor subdivision in Rockville. "I thought, 'Oh, that's a sound I'm not used to hearing: It's cars going past.' "

Funk said the constant thrum of traffic wasn't as disruptive as the pounding that woke her family during the ICC's construction over the past three years. But she's bracing for this summer, when her family will want to enjoy their back yard.

"Having to listen to this is going to be a big bummer," Funk said. "It's definitely going to affect our quality of life in the summertime."