Past them and between them nudged cars, vans and other trucks carrying furniture, women in burqas, open loads of cows and donkeys.
Amid the tidal wave of traffic, piercing the cacophony with their yelps and whistles stood the Pepsi bottle boys. They earn their meagre living by keeping the contractor trucks flowing on this section of the Jalalabad road, one of the main NATO supply routes to Kabul and one of Afghanistan's deadliest stretches of road.
"I don't like it, but I have to work and make some money," said one of the boys, Samiullah, a grimy-faced 12-year-old wearing a red baseball cap.
He was guiding traffic at one of the scariest hairpin bends, where cars rushed two abreast down from a tunnel through the mountain and three rusted tankers lay upside down in the gorge below. "I can get killed at any time."
Like all of the children on this road, Samiullah waved a flattened plastic soft drink bottle, the only tool of trade for these self-appointed traffic police.
The bottle was a symbol of his poverty; these children possess almost nothing else in the world. And it was also a signal to the truck drivers that they might want to toss a few afghanis down to him in return.
"Without us there would be a car crashed every day," he said.
The war economy touches everybody in Afghanistan and will leave a desperate hole when it is gone - not least for the Pepsi bottle boys, a prime example of how Afghans have fit their lives around America's military presence here.
These children flock from the bazaars of Pul-i-Charkhi in the poor eastern suburbs of Kabul to work for a few infernal hours on the Mahi Par Pass, but it is better than anything else they could have.
Late last year, they began to experience what life may be like after the Americans leave in 2014.
When Pakistan closed the border to NATO supply trucks in November, the trucks stopped coming, and business for these children slowed to almost nothing. Suddenly, they were out of jobs.
"Business was very low at the time," said one young man, Ziaullah, who did not know his age but looked about 20. He cut a lonely figure in a dirty green tunic amid billowing fumes on the edge of the cracked road.
"It hurt our business a lot, because usually the drivers of the trucks are paying us money, not the small cars; they usually pay 10 to 20 Pakistani rupees," or 10 or 20 cents, he said. "At that time I was earning 100 to 150 afghanis a day," $2 to $3, "so I was dividing the money for different things: 50 for bread, 50 for sugar."
Pakistan reopened the border in July, and the NATO supply convoys, driven by Pakistani and Afghan contractors, have resumed.
"I am happy if the road is open," Ziaullah said. "It is good for my business and my family." Ziaullah is the only person in his family who has a job, and he works so that his five brothers can go to school.
All of the boys up and down this five-mile stretch of winding switchback about 45 minutes east of Kabul tell life stories of deprivation and crushing poverty.
Samiullah has worked here every day for five years since his father was paralyzed and a family enemy killed his elder brother. His friend Jan Agha, 13, a quiet boy with a sad, dirty face, lost both his mother and father.
Not all of the Pepsi bottle boys are actually children.
Mohammedullah, 70, whose face is as craggy as the mountain rock looming above him, lost a leg in a mine blast during the Taliban's rule. Now he perches by one of the curving tunnels for six days a week, taking only Fridays off.
He said the drivers are crazy, and if they ignore his advice and the road gets blocked, even for a short time, "it is like the end of the world here."
"The small cars occasionally give me money, but sometime if I am lucky to catch a good and rich businessman or governor or a big military officer, then I am calling my home and telling them to cook meat soup," he said. "That day my luck is flying in the sky."
Two months ago he did not come to the road for 10 days because he had to take a family member to the hospital, and when he returned someone had taken his spot.
With the help of some soldiers and a local stall keeper, he persuaded the interloper to go farther down the mountain.
"It is like a chain," he said. "Everyone gets his part of the chain."
Most of the traffic shunters, old and young, seemed to resent their hard existence.
But not Ihsanullah, 10, another boy who stood on a high arc of road so steep the trucks struggled to a standstill and looked as though they were about to tumble backward.
A small, plump boy with a beaming face, wearing dirty sandals and a dirty gray tunic, he sported a luminous green traffic policeman's vest and gave himself the name Traffic. He said he had been working on the same spot since he was 6.
Every day, he arrives here at 5 a.m., leaves for school at 8 a.m., and then returns in the afternoon, though sometimes his head is "twisting" from the fumes and noise, he said.
He pays 10 afghanis for a bus from his house in Pul-i-Charkhi to the Jalalabad station and then jumped a ride with the truckers.
His father, a watchmaker, died two years ago from diabetes. He gives the money he earns to his mother, who divides it among his four sisters and three brothers.
American military vehicles drive this road, but he said they usually do not give him money, only Pepsi, cookies and chocolates. It is the bigger commercial trucks that give him cash, though on this day he had gotten nothing.
When a truck nosed around the corner, Ihsanullah grew excited, striding out between the cars, waving his green plastic bottle, whistling the traffic around it.
"Go, go, go!" he cried. But the cars sped by without stopping.
Then a minibus driver held a note from a window. Another truck driver tossed a 10 Pakistani rupee note into the air with a wave.
Ihsanullah scuttled and swept it up. He strode back, his chubby face lighted up. "If I am not here for a few minutes or one or two or three days, then I miss being here. I enjoy being with my friends," he said, turning back as another brightly painted truck growled over the hill. "I love it."
Sangar Rahimi contributed reporting.
© 2012, The New York Times News Service