BURLINGTON (AP) - Transportation maintenance workers in Vermont's Chittenden County have signed a new three-year-contract that takes effect July 1.

Union officials for Teamsters Local 597 say the new contract - signed Thursday - includes wage increases averaging two percent a year and access to promotions through professional certification programs.

The collective bargaining agreement was negotiated during a two-week period in May and ratified this week.

The new contract sets compensation levels for 17 maintenance workers based at the Chittenden County Transportation Authority's Burlington headquarters.

The transportation authority's buses transport 9,500 people a day in the state's largest county.