A new game, known as "Russian road roulette", is played every night at intersections throughout the Bulgarian capital.
As many as five people have been killed and many injured since the craze took hold in the summer. According to the rules, participants must drive at top speed and not apply their brakes.
The 50 or so drivers, most of them in their twenties and driving sports utility vehicles, gather at midnight at designated meeting points in the north of the city.
While lookouts watch for the police, the participants decide on the venue for the night. Other gang members are informed via texts and the gambling starts.
To win at Russian road roulette, the driver must jump red lights at busy crossroads at full speed and not collide with another vehicle, pedestrian or leave the road. If he hits an object, he loses the bet. Onlookers also take part by gambling on the outcome.
In a variation of the game, drivers approach roundabouts at high speed and go around the wrong way. Rivals also race each other along the dual carriageway of the city's ring road. On some occasions the gangs have even blocked sections of the highway to other traffic while the race takes place.
Rumen Georgiev, a taxi driver, said he was now afraid to be on the city's roads after dark. "I – like every other taxi driver in Sofia – stop at a green light to make sure nothing is coming the other way," he said. "I have to apologise to clients for the slow journey. It's a jungle out there."
