School bus drivers in the Martha’s Vineyard public school system have been paid without the required school committee authorization for nearly a year, leading the high school committee to commission an independent audit of the transportation department’s internal processes.

The committee took this action last week because Martha’s Vineyard Regional High School handles payroll for all of the Island’s public school bus drivers, acting as a fiscal agent for the individual schools.

The arrangement requires both the high school committee and the school treasurer to sign all payroll warrants.

The committee meets regularly just once a month, so the treasurer’s signature alone is enough to issue paychecks on time, but the warrants still must go to the high school committee for approval even after the fact.

Over the past school year, however, the transportation pay warrants have bypassed the committee with no explanation provided, chair Jeffrey (Skipper) Manter said.

“We have a situation here where we haven’t been presented warrants since August,” he said at the committee’s May 28 meeting.

“The school committee owns some of that for not realizing these weren’t being presented to us, [but] right or wrong, we don’t know what the issues are,” said Mr. Manter, who delegated a five-member subcommittee to define the scope of work for an independent auditor.

Meeting again on the morning of June 9, the high school committee unanimously approved a work plan calling for auditors to assess the accuracy and completeness of the transportation department’s record-keeping, protocols and internal controls, without focusing on specific employees.

“There would not be interviews of individual bus drivers, for example,” said Amy Houghton, a member of the subcommittee that drew up the audit plan.

If auditors turn up any serious problems, she said, the high school committee would meet to determine the next steps.

Mr. Manter pressed for the independent audit to have a 30-day deadline, but Ms. Houghton said that based on her conversation with the district’s advisor from the Massachusetts Association of School Committees, it’s not clear the how long the process would take once a contractor has been selected.

“I think 60 days is probably more realistic,” she said.

Ms. Houghton had made preliminary contact with three accounting firms, she said, and would send them the scope of work and query letter approved at the June 9 meeting.