BOULDER — As many as 70,000 people watched the second annual USA Pro Challenge whiz through Boulder twice on Saturday, Aug. 25, based on estimates from a variety of economic sources.

During the race, watchers were surveyed along Broadway, up Flagstaff Mountain and at various locations downtown to get information for an economic impact report expected out in a couple of weeks, said Brian Lewandowski, research associate at the Business Research Division at the Leeds School of Business at the University of Colorado-Boulder.

Boulder city officials will spend up to $10,000 for the information, Lewandowski said. Boulder City Council members plan to discuss crowd numbers at a Tuesday, Sept. 4, meeting, said Sarah Huntley, a city spokeswoman.

The sixth stage of the statewide, weeklong race started in Golden and traveled more than 100 miles on a loop route that went through Boulder and Lyons before ending atop Flagstaff Mountain.

Anecdotally, Lewandowski said survey-takers handed out $1,750 worth of $5 gift cards for Downtown Boulder Inc. businesses to non-Boulder residents who filled out the CU survey. That meant that they talked to about 370 people from out of town.

Separately, organizers said beforehand that they would hand out 30,000 free wristbands to people who hiked up Flagstaff Mountain to watch. Some workers at businesses on Pearl Street said it was the busiest they had seen the city in the past year.

“The thing to remember is, with the economic and fiscal impact from the visitors, there is more benefit to the city than just the visitor spending number,” Lewandowski said. “There’s the ‘Boulder brand,’ and the advertising that took place as it was televised.”

Streams of people, some in Spandex, others in capes and other costumes, rode their bikes or hiked up the closed Flagstaff Road to watch the race finish. Scores took in the race on gigantic TVs set up on the street and strolled around to race-related booths on the east end of the Pearl Street business district.

“It certainly was packed. It was extremely crowded,” said Sean Maher, executive director at Downtown Boulder Inc., the business organization.

Full Cycle Inc. sold large numbers of bike locks and a surprising number of bicycles that day, said Josh Nolff, sales manager. Sales of branded jerseys and other apparel were hot as well, Nolff said. The day of the bike race was “busy,” but also pretty typical for a Saturday in late August or early September, Nolff said.

“The big seller was locks. People got downtown and realized they didn’t have a lock with them,” Nolff said. “There were a lot more locals in our front door, I think, than folks from out of town.”

Sales of official USA Pro Challenge race apparel came to about $4,500 in Boulder, according to figures from organizers.

Nearby, Ted’s Montana Grill Inc. restaurant was doing a brisk business with fresh-squeezed lemonade sold on the sidewalk, said proprietor Lavonne Prescott.

At Buffalo Exchange consignment shop, the number of people through the door was lower than normal for a Saturday, however, said Marika Evanger, store manager.

“It’s worth the sacrifice for a day,” Evanger said. “I’ve never seen this many people on Pearl Street, so it’s bittersweet. I wish more people would come inside.”

The women’s sports clothing store Title Nine saw more customers, but sales were “pretty normal,” said Sarah Shea, a sales associate.

“It’s been fun. People are coming in in their biking gear,” Shea said.

Food and drink were big sellers up and down Pearl Street, as were cowbells to ring at the finish. Hotel rooms were estimated at 89 percent capacity late Friday before the race.

In Lyons, the number of people who came to town to watch the race was “unbelievable,” said Jacque Watson, economic development and communications manager. Boulder paid an estimated $250,000 to be a host of the event; Lyons was a pass-through town on the loop, Watson pointed out. A large number of people already were in Lyons for the Kinfolk Celebration music festival, and they may have swelled numbers on the streets as well, she said.

“It was claustrophobic on both sides of the street (when the race came through town),” Watson said. “Physically, it was unbelievable, at three deep to four deep.”

Crowds in both Boulder and Lyons seemed to be well-behaved and traffic control seemed to operate smoothly, Lewandowski and Watson said.

A final economic tally of the race’s economic impact across the state is expected to be released in the next few weeks by the race-hired, St. Louis-based research group IFM Global. Last year’s inaugural event drew an estimated 1 million spectators, delivering an $83.5 million economic impact to the state.