The first leg of the Triangle Expressway opens for traffic through Research Triangle Park this morning, and Nick Parsons expects an easier drive home from work this afternoon.

The six-lane toll road extends N.C. 147 south for nearly four miles from Interstate 40 to the 540 Outer Loop. There's an on-ramp near the Hopson Road gate for the U.S. Environmental Protection Agency, where Parsons works.

"It seems like it'll save me a lot of afternoon headaches," said Parsons, 25, who commutes to RTP from Brier Creek.

TriEx is the state's first modern toll road, but the N.C. Turnpike Authority won't start charging drivers to use it until Jan. 3. The ribbon-cutting at 10:30 a.m. today will serve as a soft launch for the state's toll-road era.

More toll roads and bridges are in various stages of development from Charlotte to the coast. The turnpike authority signed construction contracts in November for the 19.7-mile Monroe Connector/Bypass, to open in Union and Mecklenburg counties in 2015.

When construction on the $1 billion Triangle Expressway is finished in December 2012, the road will reach 18.8 miles from I-40 in RTP through the bustling suburbs of western Wake County to N.C. 55 at Holly Springs.

The short section opening today doesn't look like much on a big map, but commuters say it could provide big relief from rush-hour congestion on the busiest highways at the center of the region.

The shared exit for Davis Drive and Hopson Road will bring many RTP workers closer to their labs and offices. When Parsons takes TriEx south to 540, he'll bypass the usual jams on Hopson Road - a two-lane country road between Davis Drive and Miami Boulevard - and on I-40 at its frantic interchange with 540.

Chris Endicott commutes each day between home in Apex and work in Durham, so he sees RTP as a traffic obstacle rather than a destination. On a bad afternoon it can take as long as 20 minutes to crawl three miles from the Cornwallis Road exit on N.C. 147 to eastbound I-40 and the 540 interchange.

Starting today Endicott can stay on N.C. 147 as it changes from the toll-free Durham Freeway to TriEx. He figures it could cut the drive by five to 15 minutes.

"That is why I will gladly pay a buck a day to drive it," said Endicott, 31.

Transponders sell big

Toll collection for TriEx will be all electronic, with no coin collection booths. Endicott is one of about 4,000 drivers who have opened debit accounts with the turnpike authority.

When overhead sensors detect the N.C. Quick Pass transponder mounted inside his windshield, Endicott will be charged 50 cents for each one-way trip on the TriEx section between I-40 and 540.

Cameras will record license numbers. The owners of cars without transponders will get bills by mail at a higher rate - 77 cents for that same trip.

The Turnpike Authority has sold more than 4,000 transponders since October. Officials had counted on selling half that many by next June.

"It's blown our estimates out of the water," said Dane Berglund, who runs the Quick Pass customer center in Morrisville. "We were expecting only a tumbleweed business until the road opened. But we sold 1,000 transponders in the first 20 days, and it has picked up since Thanksgiving."

Drivers pay $5 for a sticker transponder, good only on North Carolina toll roads. Or for $20, they can buy a larger device that eventually will be good on toll roads in other states as well.

The turnpike authority expects next year to conclude agreements with toll agencies in other states. When that happens, drivers who use E-ZPass transponders on toll roads from Virginia to Maine and Illinois will be able to use them in North Carolina, too.

Tolls annoy some

TriEx eventually could form part of a new Raleigh bypass, when the state extends it across southern Wake from Holly Springs to Garner and I-40.

Planning for that part of the project has slowed since the General Assembly barred the state from considering any routes that would take TriEx through Garner. Environmental agencies are pressing for alternatives to the only route under consideration now because it would damage sensitive wetlands.

Many Wake residents have argued that the state should use tax money to complete the 540 Outer Loop, making it toll-free in southern Wake as it is now on the northern side of I-40. Local leaders accepted toll financing for the Loop only after the state Department of Transportation said it might have to wait another decade or two to build the road with tax money.

Jim Rozier of Raleigh, who works on Davis Drive in Morrisville, says he'll avoid using the new toll road.

"I don't see the need to pay for something I can get for free," said Rozier, 52. "That's what my gas taxes are for."

The TriEx section now under construction through western Wake will provide a six-lane option next year for drivers willing to pay for relief from the overcrowded N.C. 55.

"I know there's been a lot of criticism about it being tolled," Parsons said. "But I think it's great that a road is actually being built. It'll be a lot better than having to take 55 all the way down to Apex and Holly Springs."

Siceloff: 919-829-4527 or blogs.newsobserver.com/crosstown or twitter.com/Road_Worrier/