A 40-year tradition of allowing Commencement crowds to park for free in the Harvard Square area may end this spring, city officials said this week.

Searching for additional revenue to help counteract the effects of Proposition 2 1/2, the city council Monday ordered its chief legal counsel to investigate the legality of "capping" the meters in the Square area during Commencement, a tradition that dates back to the installation of the first meters in the early 1940s.

The council will ask the University later this spring to reimburse the city for money lost by deactivating the meters. "Under Proposition 2 1/2, we're going to have to say that if it is illegal to give services to a private corporation, then Harvard should reimburse us," city councilor Alfred E. Vellucci, who introduced the motion, said Monday.

Lewis Armistead, Harvard's assistant vice-president for government and community affairs, Monday night called the council action "unfortunate."

"I don't think this is an issue that has ever been raised before," Armistead said.

Though no councilor voted against the motion, several said it might lead to problems.

"Capping the parking meters is a traditional courtesy of the city. If we don't do it for Harvard, can we do it for funeral parlors and festive occasions?" councilor Thomas Danchy asked.

Danchy also predicted Square merchants would not be "overly happy" with an end to free parking during Commencement.