BEIJING — China has just been declared the world’s second biggest economy, and now it has a monster traffic jam to match.

Triggered by road construction, the snarl-up began 10 days ago and was 60 miles long at one point. Reaching almost to the outskirts of Beijing, traffic still creeps along in fits and starts, and the crisis could last for another three weeks, authorities say.

It’s a metaphor for a nation that sometimes chokes on its own breakneck growth.

In the worst-hit stretches of the road in northern China, drivers pass the time sitting in the shade of their immobilized trucks, playing cards, sleeping on the asphalt or bargaining with price-gouging food vendors. Many of the trucks that carry fruit and vegetables are unrefrigerated, and the cargoes are assumed to be rotting.

On Sunday, the eighth day of the near-standstill, trucks moved less than a mile on the worst section, said Zhang Minghai, a traffic director in Zhangjiakou, a city about 90 miles northwest of Beijing. China Central Television reported Tuesday that some vehicles had been stuck for five days.

No portable toilets were set up along the highway, leaving only two apparent options — hike to a service area or into the fields.

But there were no reports of violent road rage, and the main complaint heard from drivers was about villagers on bicycles making a killing selling boxed lunches, bottled water to drink and heated water for noodles.

The traffic jam built up on the Beijing-Tibet highway, on a section that links the capital to the Chinese region of Inner Mongolia. The main reason traffic has increased on this partially four-lane highway is the opening of coal mines in the northwest, vital for the booming economy that this month surpassed Japan’s in size and is now second only to America’s.

Although wages remain generally low, auto ownership and gridlock have grown so commonplace that Inner Mongolia authorities restrict cars’ movement to alternate days, based on odd or even numbers in their license plates.

The car invasion is widely felt; Guo Jifu, head of the Beijing Transportation Research Center, told a symposium Monday that vehicles on Beijing’s roads multiplied by 1,900 per day on average in the first half of this year, Xinhua, the official news agency, reported.

The immediate cause of the traffic jam is construction on one of three southbound highways feeding into Beijing.