Beijing's traffic woes have been slightly eased since a series of measures were put into effect in the first half of 2011, a senior transportation official said on Wednesday.

Liu Xiaoming, director of the Beijing Municipal Commission of Transport, said during a legislative session in the city that the average driving speed during rush hour reached 24 km per hour in the first half of the year, a 10 percent increase over that of the same period last year.

"It is a good sign that the comprehensive measures have taken effect. But tackling gridlock is still a strenuous and long-term task," he said while delivering the commission's work report at the 26th Session of the Standing Committee of the 13th Beijing Municipal People's Congress.

He said that the measures have yielded a measurable effect, even though the number of vehicles on the city's roads in July jumped by more than 600,000 in comparison to last July's number.

Beijing registered more than 4.8 million motor vehicles as of the end of last year, with 800,000 new vehicles purchased in 2010.

Growth in automobile sales has affected the city's efforts to improve its transportation infrastructure in recent years.

The city government introduced a regulation in January that curbed the growth of new vehicle sales by capping the total number of cars that could be registered in 2011 at 240,000. The regulation also required potential buyers to participate in a lottery in order to obtain new purchase permits.

Although the number of new vehicles keeps increasing, the city government has used comprehensive measures to encourage people to use public transportation, including hiking parking fees in downtown areas and improving public transportation facilities and services.

Liu said that Beijing's subway trains now arrive within two minutes, a decrease of 30 seconds from the previous average waiting time. In addition, three new subway lines are scheduled to be opened before the end of the year, according to Liu.

Beijing has also retained an "even-odd" driving regulation that it created just before the 2008 Beijing Olympics. The regulation requires private drivers to stay off the roads on different days of the week depending on whether their license plate number ends in an odd or even number.