SEATTLE — The next step in a tightening of requirements for people entering the United States will likely have little effect on businesses in U.S. towns along the Canadian border, owners and operators say.

That may be because the change today amounts to the formal start of a dry run to acquaint travelers with future requirements for written proof of U.S. or Canadian citizenship to enter the United States, and many border crossers already have made the adjustment, a number said Wednesday.

In most cases that means a passport, enhanced driver’s license and identification card, or birth certificate and standard driver’s license will not be required until after June 1, 2009.

“I don’t see it affecting us that much because people are already carrying that ID,” said David Nolan, first assistant manager at the Big 5 sporting goods store in Bellis Fair mall in Bellingham.

About 45 percent of the store’s business is from Canadians, and “no one has actually talked about it,” Nolan said.

Gary Vis, executive director of the Chamber of Commerce in Lynden, said he didn’t expect traffic delays at the border to be “any more than they’ve got now” or have much immediate impact on business.

“I think that as they phase in and become stricter, then it could cause some problems,” Vis said.

The principal immediate change is that a verbal declaration of citizenship will no longer be enough to gain entry without a potentially time-consuming secondary inspection, said Mike Milne, a U.S. Customs and Border Protection spokesman in Seattle.

Traffic through the two crossings at Blaine, northwest of Bellingham, is the third busiest along the nation’s northern border, after Buffalo, N.Y., and Detroit. Motorists entering through Lynden and Sumas and heading south to Seattle also funnel through Bellingham.

A standard driver’s license will usually be enough to enter until June 1, 2009, when the passport requirement is scheduled to go fully into effect, Milne said. Until then, those without passports or passport substitutes will be handed the same brochures explaining the new requirements that have been distributed at border crossings for months, he said.

More than half to as many as two-thirds of current travelers now meet the future standard, Milne said.

Customs agents have been working hard to notify the traveling public and transportation operators, and no significant impact is likely on traffic or waiting times, which already can exceed two hours at peak travel times between Seattle and Vancouver, B.C., he said.

“This is a transition phase,” Milne said. “We expect things to go just fine. We’ve been getting the word out as much as we can.”

Bev DenBleyker, owner of the gift shop Marin Rose in Lynden, said nearly half of her business is from Canadians and “they haven’t mentioned it.”

When the passport requirement is fully in effect, though, “I think it will discourage some,” DenBleyker said. “It definitely will.”