CHARLOTTE, N.C. As expected, the public transit agency here has requested it be given an exception to the federal charter service rule so it can provide a substantial chunk of the shuttle bus service at the Democratic National Convention in early September.

The Charlotte Area Transit System, known locally as CATS, filed its exception petition last month with the Federal Transit Administration in Washington, D.C.

In the petition, Lisa Flowers, an assistant attorney for the city of Charlotte and representing CATS, said a total of 250 buses will be needed by the Democrats for the convention.

The shuttles will transport delegates from:

The Charlotte Douglas International Airport and other airports in the area to more than 150 hotels.

Area hotels to 17 different sites that will serve as venues for various Democratic National Convention activities, including parties, receptions, caucus meetings and the convention itself.

An estimated 35,000 people will be in Charlotte for the Sept. 3-6 convention, including delegates, media, Democratic party officials and guests.

The primary venues include the Charlotte Convention Center, Bank of America Stadium, Time Warner Cable Arena, and the Charlotte Motor Speedway.

The total charter hours for the convention are expected to reach upwards of 3,000.

While 250 buses are expected to be needed over the four days of the convention, 90 vehicles have been requested by the Democrats for the four days leading up to the convention and for two days following the event.

Earlier this year, the Democrats hired three companies to manage the transportation for the convention, Event Transportation Associates of Seattle, Vectour Group of Birmingham, Ala., and Charlotte Destination Group.

This "transit management team" is considering bids from eight bus companies that submitted proposals to provide motorcoaches and other vehicles for the convention shuttle work. Four of the companies are considered local, while the other four are based elsewhere.

In its exception petition, CATS said the Democratic National Convention Committee had specifically requested the use of up to 75 air-conditioned, 40-foot, wheelchair-lift equipped transit buses to serve as convention shuttles, plus up to 10 passenger vans and 5 "special transportation vans."

It also noted that even if all eight private companies that submitted bids, plus any late comers that might be accepted by the transit management committee, assistance from CATS will be needed to fulfill the request made by the Democrats.