Stonington – The union that represents drivers that work for the company that provides the town’s school bus service have voted to unionize.

The drivers for First Student Transportation voted 20-3 Wednesday to form a union, said Teamsters local official Tom Schlink.

It was a dramatic turnaround from a 2014 vote in which drivers rejected a union by a margin of 18-16.

That vote was held amid controversy as drivers and management on both sides of the issues accused each other of intimidation, threats and other improper conduct. The vote was held under the supervision of a representative of the National Labor Relations Board.

Just before that first vote, a driver leading the union effort, Tiffany Walsh, was accused by the bus company of saying she would cut the brake lines of buses if drivers did not approve the union. The school system then said it did not want her driving Stonington students, and First Student offered her a job at its East Lyme or Norwich locations, which she did not accept.

Walsh denied the allegation, and police said they investigated and could not substantiate the charges. First Student said it would not proceed with disciplining her over the allegation. Walsh then took legal action against First Student and the school system. The outcome of those actions could not be immediately be determined on Thursday.

The school system is currently in the midst of a five-year contract with First Student that does not expire until 2018.

Schlink said he is now looking forward to sitting down with First Student and negotiating a contract before the end of the year. He said he plans to ask for an immediate raise so drivers here make what their counterparts do in other area towns, which he said is in the $18- to $19-an-hour range. He said drivers here make less than that.

First Student did not respond to a request for comment Thursday afternoon.

j.wojtas@theday.com