Just weeks before the first day of school, yellow school bus operators in the city are preparing to battle the city Department of Education, which they say is signaling a desire to drop 640 special education bus routes this fall.

A spokesman for the department, David Cantor, called the charge a “lie,” saying that every special education child who is supposed to get bus service this year will get it.

The fight began Tuesday at an annual meeting known as “the pick,” where operators choose the routes they will drive during the school year.

In the past, bus operators on contract with the city said they have arrived at these meetings with a good sense of how many routes they expect to drive during the coming school year.

People in the industry said the number of routes offered from one year to the next often fluctuates but that they are usually given a few days of advance notice, and the change is usually no more than 150 routes.

This year, bus operators said they woke up on the day of the pick to learn, at about 5:30 a.m., that the drop this year was 640.

“We’re not talking about 150 routes,” a lawyer for several major school bus operators, Peter Silverman, said. “We’re talking about 640 special education routes, which gives us special concern as to whether the board is seeking to substantially decrease the service.”

School officials would not confirm the number of bus routes offered in the pick Tuesday. They said they plan to give bus service to every special education child who is slated to receive it this year.

“We haven’t even announced the routes yet, so it’s clear that the bus companies are spreading this lie, probably to pressure us to add more buses,” Mr. Cantor said.

Mr. Silverman answered: “We don’t want them to add anything. We want them to basically run the system in a sensible, businesslike fashion. It’s not a lie.”

In the past, the education department has zeroed in on special education bus services as a place to trim costs.

A report produced last year by the consulting firm Alvarez & Marsal, which the department hired to help it slim down its bureaucracy, said the company had helped the department reduce the number of special education bus routes run each day by 101 from a forecasted amount in fiscal year 2007, avoiding $13 million in costs.

The Alvarez & Marsal report also says the company helped the department cut the costs of special education busing by reducing the number of students who are required to receive it. Such requirements are developed on a student-by-student basis in a document known as the Individualized Education Plan.

The report says the company lowered the number of students whose IEPs demand door-to-door busing by 2.7% in fiscal year 2007.

School officials said yesterday that all children will receive the bus services outlined in their IEPs.