BEIJING — New security checkpoints set up around Beijing ahead of next month's Olympics caused massive traffic jams when they went into effect Tuesday as drivers were forced to wait in long lines in China's muggy July heat.

Hundreds of checkpoints have been installed on expressways and highways leading into the capital under the "Three Lines of Defense" security program, the official Xinhua News Agency said. Security was also stepped up at the airport and on major train routes coming into Beijing.

Cars awaiting checks by armed police with sniffer dogs were backed up. Frustrated drivers read newspapers or walked impatiently along the roadside.

"Now the bad guys can't get in, but neither can the good guys," said Wang Guoqing, who was stopped on a bus at the Baimiao checkpoint east of the city.

"I've been waiting for three hours, and now I've been walking for nearly an hour down the expressway," he told AP Television News.

Car drivers and their passengers now have to show identity cards to enter Beijing, and their vehicles have to be searched for "dangerous goods," Xinhua said.

Roads leading into the city are the first line of defense, meaning mandatory police checks, with random checks planned on suburban roads and major inner-city roads as the other lines of defense, Xinhua said.

"They don't have any bomb detectors and they let cars go when they feel like it," said Huang Jiaqiang, who lives in the eastern outskirts of Beijing and goes into to town for business every day.

"I think it's only a show. They're trying to show people they are doing something, but not really doing it in an efficient way," he told AP Television News.

But traffic officials said they hadn't heard of any delays caused by the increased security.

"As long as people don't bring guns or illegal drugs into the city, they should not be concerned about the inspections," an official at the Beijing Traffic Management Bureau said. He did not give his name, as is common with officials in China.

"Inspections have been going smoothly all day and I have not heard of any delays or mishaps," he said.

China is mounting a huge security push for the Olympic Games, surrounding venues with thousands of police, saying the games are vulnerable to terrorist attacks. China has prepared an anti-terror force of nearly 100,000 commandos, police and troops, Xinhua said.

Beijing residents deemed a security threat — such as petitioners seeking redress for grievances in the capital, vagrants, migrant workers and prostitutes — have been cleared out of the city or are being monitored by police. Temporary residence permits have been introduced for those who do not have Beijing resident permits.

Security checks were also introduced on the city's subway last month.

On Monday, a senior Chinese security official stressed that security checks had to be both strict and convenient, Xinhua said.

"During the Olympics security work, we should not only stick to strictness and details, but also ensure civilized and convenient inspections for people," said Zhou Yongkang, who handles law and order issues on the Communist Party's supreme nine-member Politburo Standing Committee.