The line starts before dawn, the motorcycles descending on gas stations in a single-cylindered clatter that has become the starting bell for the lunar new year travel season.
It is the most important date on the Chinese calendar, and every year its arrival launches the biggest movement of people on Earth.
Among them are a half-million people on two wheels, many of them migrant workers who spend the rest of the year toiling in factories. In China, they've been dubbed the "motorcycle army," and their travels through rain and cold have made the quasi-heroic icons of the trials endured by those on the national stampede back to the farmlands and mountain villages where many grew up.
"I actually started crying these last few days, watching the news," said Luo Zijin, who made the commute himself in the 1990s, before taking a job driving a taxi in Foshan, one of the factory centres that makes up the Pearl River Delta manufacturing heartland where the motorcycle army spends most of the year. "I feel so much pity for them – it's a tough road home."
And it remains a tough life for those on two wheels, one of the more visible parts of what remains an enormous Chinese population that has yet to see the comforts of middle-class life.
As they prepare for the holidays, they load their bikes with milk powder, cookies, candies, clothes, bundles of cash and, occasionally, furniture and televisions. Some couples bring children, riding three to a bike; others carry pets hundreds of kilometres in the open air. Still others are young men turning a lengthy holiday into a chance to briefly break free of the drudgery of jobs where they rarely get much time off – save at lunar new year, known locally as spring festival, when they can get up to a month to go home.
This year, the journey took on added difficulty for those pouring onto the highways around Guangzhou after the city in southern China saw its first snow in 67 years.
"And it's going to be colder the further away we go," said Li Changcun, 22, who works in a motorcycle factory and will take two days to ride more than 900 kilometres to his home not far from the Vietnamese border in western Guangxi province.
"For those of us who really like it, it feels like flying. I really enjoy it," said his riding buddy, Nong Guangfu, 23. They could take a train, but it's twice the price. The motorcycle "is cheaper, and we have more freedom," he said.
For days, long columns of motorcycles fan outward from Guangdong province and the broader Pearl River Delta. The region is crowded with factories and millions of people who assemble the world's air conditioners, light switches, electronic toys and vast numbers of other goods.
During spring festival, most of them go home. Those who choose to travel by motorcycle are motivated by cost, the difficulty of getting train and bus tickets and a desire to have their own set of wheels at home when they get there.
Some ride nearly 1,000 kilometres to visit parents, grandparents and children they might see only once or twice a year.
Huang Deyong, 39, has lashed a pair of stools to the back of his motorcycle to make a cage that will protect the milk powder he is bringing home. Perched on top is a bag of new clothes for family.
He is eager to go. As they do every year, his kids – a 14-year-old daughter and an 11-year-old son – have already called to ask when he will leave. "When I am riding, all I can think about is how much I want to get there quickly," he said.
Mr. Huang, who cuts cloth at a garment factory, is an old hand: He first rode home in 1999, before the roads had medians. Now on his second motorcycle, he has prepared for his latest ride home by oiling his chain and completing a thorough inspection. He worries, though, about the road ahead. It is far busier than it once was, and most years accidents claim some of those on the motorcycle migration.
"In the past, it was not cheap to buy a motorcycle. We had low salaries, so there weren't many who owned them," he said. But that's all changed, and fast. Roughly 150,000 people rode motorcycles home in 2010. Last year, an estimated 600,000 joined the Guangdong province motorcycle army.
In that time, the minimum monthly salary in Guangdong province has nearly doubled to 1,895 yuan, or $400 – and the average actual salary is 2 1/2 times that.
For migrant workers in recent years, "there has been significant improvement in living standards," said Russell Smyth, an economist at Melbourne, Australia-based Monash University who has studied China's migrant workers.
Yet, the motorcycle army exists in part because salaries remain comparatively low for vast numbers of Chinese.
"Those who are rich probably buy cars. Riding a motorcycle is very cold," says Liang Guowu, 42, who dressed in seven layers against the chill.
The members of China's rising middle class have largely upgraded to four wheels: Last year, Chinese people bought nearly twice as many cars as motorcycles.
But the country still sold 11.1 million motorbikes, and China's per-capita GDP remains one-seventh that of the United States. Although China has seen more people emerge from poverty than any other country in history in recent decades, about 200 million Chinese remain poor by international standards, living on less than $1.25 (U.S.) a day. Members of the motorcycle army occupy another large swath of the population trapped in the "middle income" category – not quite poor, but still not comfortably well-off – a place from which Chinese policy-makers worry their economy will have trouble emerging.
"The migrants are still not really becoming the middle class," said Kam Wing Chan, a specialist in Chinese migrant issues at the University of Washington. Their economic progress has been blocked, in part, by China's household registration system, which makes migrants second-class citizens in cities – and often keeps their children far away, in rural homes where they can access government schooling.
"If you want to grow the middle class in a massive way, then you really need to fix some of these obstacles," Prof. Chan said.
But those fixes, if they come, will be slow to arrive.
In the meantime, the hardships of the motorcycle army have captured China's imagination. Sinopec, one of the country's energy giants, offered free gas to the first 10,000 riders heading west out of Foshan, a major factory centre. At the Shunde filling station, Sinopec equipped a baby room with a changing table, diapers, wet wipes and bottle warmers, and fitted a lounge with comfortable chairs and a heater in front of a big-screen TV. Employees handed out free tea, porridge and tools, and stuck stickers with the Sinopec logo on the motorcycles that stopped.
It's great publicity: The motorcycle army makes national news in China, headlining a holiday migration that this year will see Chinese people take 2.91 billion trips, up 3.6 per cent over last year.
The riders were grateful, particularly for the free gas. But the lounge was occupied by Sinopec attendants. Those on motorcycles were keen to get going.
"I just want to be home as quickly as we can, because our child is there," said Feng Hua, 27, who was riding with her husband. "And we only get home two or three times a year."
With a report from Yu Mei