In the hustle and bustle of Bangkok, there are private groups that try to help accident victims by taking them to hospitals.
The car jumps another red light at breakneck speed as Paitoon Kaewkieu, one of Bangkok's so-called "bodysnatchers", dodges through the city's notorious traffic to the scene of yet another accident.
The 28-year-old is a volunteer for the Ruamkatanyu Foundation, one of several private groups that help Bangkok's rudimentary ambulance services by either ferrying injured people to hospital or taking the dead for autopsy.
"You learn through experience," grins Paitoon, who has no licence or training for emergency driving, as the speedometer hits a terrifying 160 kilometres an hour (100 miles per hour).
This is how he and his girlfriend, who accompanies him in the car, spend every other evening until about 3.00am, after finishing their day jobs.
"I just like the feeling I'm helping people -- and I also enjoy the adrenaline rush," adds Paitoon.
Groups like Ruamkatanyu say they are financed entirely by donations, with many people in predominantly Buddhist Thailand believing that giving money to rescue services will bring them good karma.
The volunteers do the work in their free time. They have received a basic, two-day medical training course but it is down to them to buy their green uniforms, walkie-talkies and flashing lights for their cars.
For people like Noppadol Srithongkham, who is a paid supervisor to the volunteers at the Ruamkatanyu Foundation, the job has become something of an macabre obsession.
"You can see this one's skin had already turned green," Noppadol says as he flicks through a stack of photographs showing some of the thousands of dead bodies he has picked up during his time.
"Working with corpses is easy for me," he says. "I don't think it's strange. It's my job and I do it the best I can."
Some pictures show suicides. Others are of murder victims, with blood pouring from gunshot wounds to the face. But most are of people who perished in accidents on the city's streets.
"A passing motorcyclist was staring at one accident, he turned and didn't realise that the pick-up truck in front was braking and crashed right into it. He was killed outright," Noppadol says.
"I told the autopsy doctor, 'Doctor, Doctor! Don't go anywhere; there's another case on the other side of the road,'" he chuckles to himself. "What are Thai people like?"
But there's also a darker side to the service that has contributed to the unflattering nickname given to the volunteers. With rival hospitals competing for trade, one volunteer says it's possible to pick up backhanders.
"We can get between 500 and 1,000 Baht (14 and 28 dollars) from the hospitals for each injured person," Sagachai Supakrerakoon says. "It depends on the case. Hospitals pay different amounts."
Stories of volunteers from the two main rival foundations fighting over the injured to get their cut used to be common. But then Thai authorities stepped in to end the sometimes literal tug-of-war over bodies.
They divided the city into two: one night Ruamkatanyu covers the north while its rival Poh Teck Tung covers the south. The next night they swap over, allowing both organisations the chance to cover the city's hotspots.
The volunteers like Paitoon and Noppadol wait on threadbare mats in a deserted car park off one of Bangkok's main highways. "There go our customers," remarks one volunteer drily as a green traffic light unleashes a swarm of motorbikes.
Soon, the call they've been waiting for comes over the radio: an accident nearby with dead and injured. Everyone leaps to their feet, runs to their cars and they're away, tailgating the foundation's official ambulances.
Paitoon and his girlfriend jump out of the car at the scene of the accident. A crumpled car blocks the road and a smashed taxi has spun off into a ditch -- but this time they're too late.
"No one was seriously hurt and there were no dead like we heard on the radio," he says. "There were only minor injuries -- and another volunteer team took two people to hospital."