BEIJING - Traffic in the capital looks set to get even worse over the next few weeks, authorities have warned.

The city's transport commission has predicted an increase in congestion throughout September, largely due to the start of the new school year and the upcoming Mid-Autumn Festival and National Day holiday.

"Based on experience, September sees more traffic jams than other months," the commission said in a news release. "This is because people are visiting relatives and friends during the holidays, and parents are driving their children to school."

September proved the worst month for road congestion in 2009 and 2010, the commission said. It added: "This year, Mid-Autumn Festival (on Sept 12) falls close to the start of the new school year (on Sept 1), so there's a high risk of jams on rainy days."

Meanwhile, the number of vehicles traveling on Beijing roads continues to rise, with the total now 4.95 million, 450,000 more than in 2010.

Drivers are already feeling the brunt of the worsening traffic conditions.

"The jams are mounting up, especially at times when schools are opening and closing," said taxi driver Dou Keying.

He agreed that September is a terrible time for drivers. "It takes time to adapt to the frequent jams after the summer vacation," he said. "I don't understand why parents have to drive their children right to the school gates. The only result is everybody's time is wasted in traffic jams."

As part of efforts to alleviate congestion, the transport commission is launching three new bus lines and increasing the frequency of subway trains to encourage more commuters to use public transit.

"The new lines will target 20 communities, including Huilongguan and Beiyuan, and will boost services to Lianyidong Road and Chunhua Road. The service hours will also be extended," said the commission.

Trucks used for construction or environmental maintenance will this month be banned from the roads during rush hours, 7 am to 9 am and 5 pm to 8 pm.

"We will also strive to make sure that 95 percent of taxis are on duty every day, and taxis drivers who refuse to take passengers will be targeted," according to the news release.

Beijing's traffic woes have already been eased this year through various measures, including the so-called license plate lottery, increased parking fees and restrictions on cars from outside the city.

The average speed during rush hour was 24 km/h in the first six months of this year, a 10-percent increase on the same period last year, according to a report by the traffic authority.