Their work has become such an essential part of life in Seoul and other major cities of South Korea that the national statistical office last year began monitoring the price of replacement driver services as an element in calculating the benchmark consumer price index. An estimated 100,000 replacement drivers handle 700,000 customers a day across the country, the number increasing by 30 percent on Fridays, according to the Korea Service Driver Society, a lobby for replacement drivers.
"The peak is between 11 p.m. and 1 a.m.," Hur Rak said. "But I usually don't get to bed until 7 a.m. I suffer chronic fatigue, but it's the way I make my living."
This whole business is seen as a compromise between competing forces in Seoul: the capital's nightlife and a police force determined to crack down on drunken driving.
The Korean emphasis on teamwork means frequent group dinners, and plenty of "bombs," a glass of beer with a shot of whiskey in it. Now, however, the police are putting up random roadblocks to catch drunken drivers, who risk losing their licenses.
Some simply abandon their cars at the sight of a roadblock and flee, figuring that illegal parking is a far lesser crime.
Besides the night hours and low job status, replacement drivers have an obvious occupational hazard: their customers, who can become abusive. There have been reports of a replacement driver stopping in traffic, locking the car and walking away, leaving the customer kicking and raving. "My teenage son once asked me not to tell his friends what my job was,". Hur said.
The most common problem, he said, is having customers who "can't tell north from south, east from west, in their own neighborhood." Then there are those who refuse to wake up. Drivers often are forced to shuffle through the customer's wallet to look for a home address. (Complaints of theft are not uncommon.) Or they check a cellphone to find a home telephone number.
"If the customer is very drunk, I make sure I get his home number from his sober drinking partners," Hur said. "You can struggle with a drunken man for half an hour, pleading and shaking him, but he wouldn't stir, and you are stuck with him in a forest of apartment blocks well past midnight, wasting time that you could use to get more orders. But when his wife comes out and says two words, 'Wake up!' and I am not making this up he comes right around."
Some orders take Hur outside Seoul to places where there is no public transportation or where it has stopped running for the night, complicating his journey back to the capital. "You walk and run to reach a gas station or a toll gate," he said. "There, you hitch a ride on a truck bound for Seoul. You constantly think how fast and cheaply you can return to Seoul to get another order."
He said he sometimes spent time at a 24-hour cafe, waiting for bus service to resume at 5 a.m. "About 80 percent of the passengers on the first bus bound for Seoul are replacement drivers," he said. "We recognize each other by how weary we look."
Hur starts his evening by traveling to an underground bookstore plaza at the bustling Chongno subway station in central Seoul, where he waits with a dozen other drivers to receive their companies' orders.
When they come, the orders usually include the customer's cellphone number, which Hur calls to locate him. "You take a taxi and run, only to find that your customer had called more than one company and already took off with the one who got to him first," Hur said. "This is the most frustrating. I am always in a rush."
Many replacement drivers are part-timers, cashiers, students or salesmen who need extra income to pay debts. There are husbands and wives working as teams, usually with the woman following the man in a car to pick him up after the customer is dropped off. There are also female replacement drivers for female customers.
Hur began working full time as a replacement driver after he went bankrupt and lost his house more than three years ago.
He now makes a little over $2,400 a month. After paying his expenses, he still manages to send around $1,000 a month to his wife and son, who live with his mother in a rural town.
"Like most people, I am doing this only temporarily until a better job comes along and helps me get back on my feet and reunite with my family," Mr. Hur said. "Until that happens, I drive drunks."