Two separate motor-vehicle accidents occurred on South St. Sunday, according to the Waltham Police Department. Both drivers, who are not University-affiliated, sustained minor injuries.Though no pedestrians were injured in the accidents, safety has long been a concern on South Street, where last fall a student was hit by a car as she crossed near Linsey Pool. At least three pedestrians have been struck by vehicles on South Street in the last six years.

The first incident Sunday happened around noon, police said, when a tire on a 2001 Toyota blew. The driver, Paul Wasswa, a resident of Malden, Mass., then careened off the road, through the fence and into the Gosman Sports and Convocation Center parking lot.

"We're just fortunate no one was hurt," Director of Public Safety Ed Callahan said, adding also that fortunately, nobody was standing in the parking lot.

The incident led to minor damage to at least six parked cars and a 39-foot gap in the fence, the police report states.

Jane Low, a local resident, was driving behind Wasswa's car when it veered off the road.

"The guy was driving normally. All of the sudden he started shimmying," she said. "He is absolutely so lucky. God was with him."

Before ambulances arrived, Wasswa was treated on scene by Assaf Ben-Atar '07, who has training as an EMT.

Ben-Atar said he found Wasswa sitting 20-feet from his car, on the curb, and that Wasswa didn't recall the accident.

"[The driver] was complaining of chest pains, both air bags had been deployed," Ben-Attar said. "His car was totaled-there was a lot of damage, but other cars were in surprisingly decent shape."

Later that day, a motorcyclist traveling on South St. lost control of his gears and struck a curb, police reports said.

The other accident, which occurred about 9:15 p.m., involved only the rider, Eleazar Fernandez, drawing four police cars and a fire truck behind Slosberg Music Building and the Village.

Waltham Sgt. Anthony Vazquez said Fernandez was temporarily unconscious. "His motorcycle is probably totaled," Vazquez added.

The police reports said the gears on the motorcycle became stuck, causing Fernandez to lose control. Vazquez said Fernandez was treated for superficial wounds.

Heightened police presence on campus Monday was due to the five-year anniversary of the Sept. 11 attacks, Callahan said, not because of the accidents.