A tanker truck carrying thousands of gallons of gasoline overturned on a major city highway yesterday and caught fire, spewing thick black smoke that could be seen for miles.

The driver was able to get out, and no one else was hurt, the chief of the police Queens North Bureau Command, Jim Tuller, said at a news conference near the scene.

The truck was carrying 8,000 gallons of gasoline when it overturned at about 11:53 a.m. near the Roosevelt Avenue exit of the six-lane Brooklyn-Queens Expressway in Queens, a director at the city’s Office of Emergency Management, Michael Lee, said at the scene.

“The driver appeared to lose control, and the truck flipped over,” Mr. Tuller said. He said the driver, who was not identified, suffered minor injuries and was able to walk away.

It was not immediately known what caused the Mobil truck to overturn, Mr. Tuller said, adding that no other vehicle was involved in the accident.

The accident occurred directly beneath a temporary overpass, which collapsed onto the truck, Mr. Lee said.

“The heat of the fire caused the [overpass] beams to come down,” he said.

The no. 7 subway line, which runs on elevated tracks just beyond the overpass, was shut down in both directions between Queensboro Plaza and Willets Point for a few hours because of concern that sparks from subway tracks could land on the spill.

Both officials said every effort would be made to get the roadway cleared by today’s morning rush.