When the school year came to a close at 11:30 a.m. today, so too did the city’s infamous “rubber rooms,” the reassignment centers for teachers the city says are unfit for the classroom.

Like all teachers, teachers awaiting trial on misconduct or incompetence charges don’t have to work over the summer. Because of a deal the city and teachers union struck in April, those whose cases are still pending at the end of the summer will report for duty Sept. 7 not to a rubber room but to a school or district office, where they will do administrative work. In the past, teachers who finished the school year in a rubber room would begin the next one still languishing there.

United Federation of Teachers President Michael Mulgrew said today that the city had begun to make headway on its promise to clear the backlog of cases against teachers by December. In April, there were about 650 cases open against teachers.

“Cases are moving much faster now that they have agreed to actually follow the timelines,” Mulgrew said. “They’re surveying all the cases, which they really were not doing, and they’re saying this is ridiculous, this is ridiculous. They’re clearing a lot just by going through each and every one. … The numbers are dropping quickly.”

The city estimated it was spending about $30 million annually to pay teachers to sit in rubber rooms, which had drawn ridicule from the New Yorker magazine and even provided a storyline for the final episode of the television series “Law and Order.”