APEX — The 5 o’clock crush on N.C. 55 is so bad some days that Craig Gartside prefers to stay at work an extra hour.

“If you leave the office at 5 p.m. and try to get home, 55 is just mobbed,” Gartside, who is in his 50s, said Monday. It can take an hour to get from his Research Triangle Park office to his home in Apex.

“So I delay my exit until the traffic subsides. At 6 p.m. it’s not so bad, and I can actually get home in 20 minutes.”

Gartside says he’ll try out an alternative to the overloaded N.C. 55 starting Aug. 1, when the state opens the second leg of North Carolina’s first modern toll road, the Triangle Expressway. It will be a six-lane, 6.6-mile extension of the 540 Outer Loop south from N.C. 55 at RTP to U.S. 64 in Apex.

N.C. 55 is the primary north-south road through the busy shopping centers and lush subdivisions of western Wake County. It hasn’t kept up with the region’s relentless growth over the past 20 years.

Mostly a five-lane run except for a two-lane bottleneck where it squeezes through the center of Apex, N.C. 55 struggles under the load of 30,000 cars and trucks each day. Speed limits change from 45 to 50 mph – but with traffic signals every half-mile, the usual rush-hour pace is stop-and-crawl.

When the third leg of TriEx opens in December, extending 540 another 6 miles farther south to Holly Springs, it will complete a long-awaited alternative for western Wake commuters who are willing to pay for relief from N.C. 55 congestion.

Or, in Heather Baxter’s case, from N.C. 751 congestion.

She commutes from her southern Durham home to work at the Harris Nuclear Plant in southern Wake, and she is eager for that Aug. 1 ribbon-cutting.

“The afternoon traffic on 751 is unbearable,” said Baxter, 41. “When I leave work at 5, 751 has become packed with cars going in both directions. And it’s just gotten worse over the years. I am most certainly going to pay the toll when the road is fully open.”

The state Department of Transportation opened the first 3.4-mile link of TriEx in December, an extension of N.C. 147 from I-40 through southern RTP. It carries about 2,700 cars a day. The section that opens Aug. 1 is connected to it by an older stretch of N.C. 540 that was built entirely with tax dollars.

State and federal agencies made an unusual agreement in 2007 to convert this part of 540 to a toll-road, from N.C. 54 to N.C. 55. The deal turned TriEx into a single 18.8-mile toll project – instead of a pair of shorter toll roads separated from each other by less than two miles.

More than 20,000 drivers a day have been using this section of 540 without charge for a few years, but they’ll start paying tolls next month. A one-way trip on that part of 540 will cost 52 cents for drivers who have electronic N.C. Quick Pass transponders. Cameras will record the licenses plates of toll-road users whose cars are not equipped with transponders. They will be billed by mail at a rate of 80 cents per one-way trip.

Howard Wilcox has retired from the commuting life, but he uses that stretch of 540 almost every day. Rather than start paying a toll, he says he’ll find back-road routes for his trips to Sam’s Club, to church and to the golf course.

“I think it’s just crazy to have to pay a toll on that 3-mile stretch, a road that’s already been built and paid for with my tax dollars,” said Wilcox, 71, who lives just off N.C. 55 in Cary.

Ronda Hintermeister says the first short leg of TriEx has trimmed as much as 10 minutes off her daily drive from Apex to Durham, and she has high hopes for the section that will open Aug. 1 near her home off U.S. 64.

“I get tired of sitting in traffic on Highway 55,” said Hintermeister, 45. “It stinks that we have to pay for it. But convenience is expensive, I guess.”

Make contact: 919-829-4527 or bruce.siceloff@newsobserver.com. On the Web at twitter.com/Road_Worrier/ and blogs.newsobserver.com/crosstown/. Please include address and daytime phone.