"They all said it's your problem, we can't help you," he says.
For a month, Khan weighed his fear of restarting the project against the chance he could still turn a profit.
The Public Works Ministry and the Chinese _ who Steffensen says were mostly holed up in their field compound for safety _ begged Khan to finish the job.
When the Interior Ministry announced it was sending 500 police to boost security for road crews _ with an unprecedented $2.5 million from the ADB _ he decided to go back.
The new force's strength, though, was diluted along the way.
The provincial governor and police chief diverted at least two dozen of the reinforcements to their personal security details, according to Maj. Gen. Sayed Kamal Sadat, who leads the national force tasked with protecting Afghanistan's highways. Both officials deny the allegations.
Provincial police commanders seized 400 of the 500 new Kalashnikov rifles the police were supposed to get, handing their old ones to the reinforcements, according to another Interior Ministry official, Habib Rahman. At least half the 40 new police trucks allotted for the operation were also diverted to local commanders, he said.
And because of an old dispute between Sadat and the provincial police chief, the reinforcements were not supplied with enough food, water or ammunition, Rahman said.
Some of the 500 police were deployed to guard road workers and their facilities, while others joined with local police to set up dozens of check-posts guarding the highway.
Sadat says seven of the police have been killed in rocket attacks so far. And at least one of the road posts has typically been attacked each night with grenades or small arms fire by motorcycle-bound Taliban, according to an ADB security official who declined to be named because of the sensitivity of the subject. The official said police at a couple of posts had also deserted and joined the Taliban.
Nevertheless, Sadat insists the force has been effective. Security has improved.
The second ambush came in September. Up to 40 gunmen hiding in mud-brick houses along the road opened fire with rockets and machine guns, according to police Capt. Najib, who heads the newly deployed force and like many Afghans, uses only one name.
The gunbattle lasted two hours. When it was over, two police were dead and one of Khan's rented road graders was ablaze, Najib said.
Khan was about two kilometers (one mile) away, and fled at the start.
He has not gone back, and it's unclear if he ever will.
In November, ADB terminated its contract with China Railways Corp., deeming it incapable of finishing the job on time. Khan says the Chinese paid less than a quarter of his projected expenses, leaving him tens of thousands of dollars in debt for labor and machine rentals. The Public Works Ministry says it will force China Railways to pay whatever it owes its subcontractors.
Even in the best scenario, though, Khan will only break even, and still owe tens of thousands for the ransom.
He estimates only two-thirds of his tiny road is complete.
In total, only around 200 kilometers (125 miles) of the Ring Road remains to be built. But it may take three years to finish it all _ or more.
Finding a contractor willing to replace China Railways and hire somebody like Khan will be tough because "nobody in their right mind wants to work up there," Steffensen says.
The final sector, just west of Khan's road, will be even tougher: it crosses a Taliban stronghold called the Bala Murghab River Valley that is so full of militants it's likely to be "shooting gallery" for troops and road crews, Steffensen says.
With no capable contractors willing to take on the unfinished sections, Steffensen appealed for the U.S. Army Corps of Engineers to help _ at ADB's expense. A U.S. diplomat swiftly scotched the idea, Steffensen says, telling him the Army Corps is "spread too thin."
In Kabul, Khan says he recognizes the voices who call him every few days: they are the ones who tortured him.
They insult him, vow to recapture him, and warn their agents are watching. Sometimes they describe what he is wearing, or where he has been.
"We told you to quit building this road," they say. "We should have killed you when we had the chance."
There are other harassing calls, from the people to whom Khan is in debt.
He keeps answering his phone because he hopes he will find a kinder voice on the line, one that will get him out of this mess. A sympathetic government official, perhaps, or help from the international development community which is driving men like Khan to help them.
"I lost my life over this road," he says bitterly. "The government insists it be built, but they don't care about the people who build it."
Asked if he will return north to finish his job, sometimes he answers yes, sometimes no.
Beside him, on the faded red carpet, Khan's phone is ringing again.