A sinkhole formed suddenly on Mt. Auburn St. near Quincy House yesterday, swallowing part of a car and delaying traffic for hours.

A car was driving down Mt. Auburn St. near the corner of DeWolfe St. when the road in front of it caved in and created a hole about five feet deep.

"A few chips of the road fell in, then more and more," said Barak Goodman '85, who was standing on a nearby corner. The right front end of the car fell into the hole as it formed, said Goodman, who was visiting a relative in Cambridge this weekend.

The driver of the car thought the gap was only a pothole and was about to attempt to drive over the hole, Goodman said.

"I went over to the door and told her to get out of the car and not to drive over it," he said. "She burst into tears when she got out of the car."

The car, a Volkswagen Rabbit, was sitting on three tires with the fourth suspended in the air above the hole, he said.

People on the scene told the driver to sue the city, Goodman said. "The street was closed off," said Mike Walsh of the Cambridge Police Department.

Traffic officials detoured passing cars onto Memorial Drive by way of DeWolfe St. Walsh said. "Cars couldn't see it [the hole] until they were right up next to it," Goodman said.

A tow truck was sent to pull the car out of the hole, Walsh added. "It didn't fully engulf the vehicle. Only the front part fell in," he said.

Public Works officials filled the sinkhole with sand. They determined that the street was safe to open about five hours after the hole first formed, Walsh said.

Signs reading "Emergency Regulation--No Parking," were placed near the filled sinkhole.

A police officer on the scene said that the sinkhole may have been caused by water.