LANGFANG, China — Road checkpoints erected this week around Beijing to boost security for the Olympic Games have put a chokehold on regional commerce and created ripples likely to reach as far as U.S. store shelves in time for the holiday shopping season.

Traffic disruptions could affect a gamut of consumer products ranging from flat-panel televisions and other electronics to auto parts and other goods, said Bryan Scott Larkin, a marketing director at GXS, a Gaithersburg, Md., company that helps clients streamline their supply chains.

"You could see fewer products on the shelves and higher prices at Christmas because of the impact that this will have," Larkin said.

Larkin noted that security, transport and environmental measures affect parts of six nearby provinces, an area much larger than just greater Beijing.

Many foreign companies that are dependent on Beijing-area factories for components were caught by surprise at the traffic clampdown, he said, and some don't want to admit that they face disruptions.

"I can see companies not talking about it because they don't want to alarm anyone, especially with all the other problems in the (U.S.) economy," Larkin said.

China suffered transport mayhem from February snowstorms and a devastating May earthquake in Sichuan province, and Larkin said the latest disruptions could influence corporate managers to build new production plants away from China.

The first bottlenecks began July 1, when authorities barred heavy polluting trucks from entering Beijing, allowing only trucks with cleaner-burning engines.

"During the next two months, big trucks can enter the city only from midnight until 6 in the morning," said Jiao Shufeng, a driver.

Jiao spoke near a checkpoint in Langfang, 25 miles southeast of the capital, where drivers lazed in the shade under their trucks, waiting to offload goods to other vehicles with special permits to circulate in Beijing.

Long lines of trucks formed at dozens of highway checkpoints around China's capital, leaving many drivers grumbling that they were unable to make deliveries.

"We are operating just for the most top-priority clients," said Cong Peichao, a 37-year-old sales manager, as he moved merchandise from one provincial truck to another approved to enter Beijing.

A series of staggered security and environmental measures are taking effect for a two-month period around the Aug. 8-24 Beijing Olympic Games and the Sept. 6-17 Paralympics. Officials hope that the measures will ensure the safety of spectators and athletes and clear the smoggy air that routinely cloaks the capital.

This week, police set up three concentric rings of checkpoints along all major roads leading into Beijing. At outer rings in surrounding Hebei province, officers with sniffer dogs and electronic scanners checked all vehicles, searching for hazardous materials and "dangerous" people allegedly seeking to disrupt the Olympic Games.

The roadblocks created bottlenecks and traffic jams, some longer than a mile. All vehicles registered outside Beijing were thoroughly examined and allowed entry only with special documents.

Further restrictions in coming days will hamper deliveries to auto plants, supermarkets, apparel factories and high-tech plants and shops, and will affect services such as special delivery vehicles.

On Sunday, Beijing will order about half the city's 3.3 million vehicles off the road in a system that allows them to circulate on alternate days, depending on whether they have license plates ending in odd or even numbers, in a move to cut auto emissions.

Companies and car owners in Beijing scrambled to find vehicles to cope with the two-month odd-even license plate restrictions, even as new measures were announced. Authorities said Thursday that they'd halt flights into and out of the capital's busy airport for four hours on the night of Aug. 8 during the spectacular opening ceremonies planned for the games.

Many construction sites around metropolitan Beijing ground to a halt this week, ordered shut to prevent construction dust from adding to air pollution. Streams of migrant workers headed to the train station, ordered to return to their home provinces.

Hundreds, and maybe thousands, of small factories in greater Beijing shut their doors and sent workers home. Others were still trying to rev up production in an 11th-hour tactic.

"From July 25, we have to close the factory for two months," said Xiang Wancheng, a sales manager at the RiseSun cement factory. To prepare for the closure, "we increased production 30 percent in June and July," he said.