Wook Choe ’07, injured in a bus accident Monday, was in fair condition at Yale-New Haven Hospital as of 12:40 a.m. today, although his condition had shifted between critical and fair throughout the day Tuesday.

On Tuesday, Choe’s condition had improved from critical in the morning to fair by the afternoon, and back to critical by the evening, the hospital said. His condition was upgraded to fair again by early Thursday morning.

Saybrook Master Mary Miller, who visited Choe last night, said he was resting comfortably yesterday and both of his parents are now with him at the hospital.

“He is cracking jokes and feeling a lot better,” Miller said. “He is asking to have his friends come visit, which is always a good sign.”

The accident occurred Monday at 12:58 p.m. in front of Sheffield-Sterling-Strathcona Hall as the bus completed a right turn from Grove Street onto Prospect Street. Before the collision, the bus was traveling on Grove approaching Woolsey Hall, New Haven Police Department spokeswoman Bonnie Winchester said.

“The bus driver took a right turn onto Prospect Street and, as he was making the turn, heard a sound towards the rear of the bus,” Winchester said. “Witnesses said that a man walked into the side of the bus near the back.”

After the accident, Choe — who was accompanied by his mother when the collision occurred — was transported by ambulance to Yale-New Haven. CT Transit spokesman Philip Fry said Choe had a bruise on his forehead when he was picked up by the ambulance.

The driver of the bus, whom Fry declined to identify, has worked for CT Transit for 25 years and has had accidents in only four of those years. Fry said that record would place him among CT Transit’s better drivers. Fry said he thinks the collision occurred in the street, and the bus did not ride onto the sidewalk during the turn to strike Choe there.

“Passengers in the bus seem to support the position that the individual walked into the bus,” Fry said.

Fry said the company’s claims department will assess the collision after the police investigation is completed to determine who was at fault.

Miller sent an e-mail to Saybrook students Wednesday morning alerting them to the accident and offering to collect cards and notes to be delivered to Choe. Because many gifts, including flowers, are prohibited in the intensive care unit, Miller said students have responded to her e-mails in creative ways.

“A student rushed over with a mix of some of his favorite songs that would cheer him up,” Miller said.