Chapel Hill, Carrboro and UNC have agreed on a debt financing plan to add 10 to 15 new buses to start replacing a large portion of the current bus fleet which is past its useful life.

“Forty two of our 99 fixed-route buses are past their useful life,” said Chapel Hill Transit director Brian Litchfield. “The federal government puts 12 years on a fixed-route bus, 42 of our 99 are at least 14 years old, with our oldest around 21.”

The older buses require more time and money to maintain and can also be a safety concern.

Litchfield said some are so old that parts are no longer manufactured, so the town has to keep a few buses no longer in use to raid for parts.

“As our older buses have gotten older we’ve put more and more miles on our newer buses,” he said. “Some of our newest buses have miles on them for buses that are about twice their age.”

In order to help solve the problem, the Chapel Hill Town Council authorized the town manager to enter into an agreement with Gilling LLC, which enables the town to purchase up to 53 new buses, although it does not require the town to purchase any.

“These will generally be used to replace buses that are well beyond their useful life,” Litchfield said. “We’ll start replacing likely the oldest buses first. The only caveat to that would be any bus that has received a new engine or transmission would move down on that list.”

In a separate agreement, also approved by the council Monday, the town will contribute around $235,000 annually to help pay for 10-15 new buses, which Litchfield said will be determined based on the price of the buses. UNC will contribute around $444,000 and Carrboro will add around $83,000.

“We set up a cost-sharing arrangement that is based on the individual’s current contribution to the transit budget,” he said. “The university paying 58 percent, Chapel Hill paying 31 percent and Carrboro paying 11 percent.”

The council is also considering fuel efficiency for its new buses. The last group of buses purchased run on clean diesel, which Litchfield said emits just 5 percent of what the older buses did.

Councilman Ed Harrison said he wanted the town to conduct a study to look into more fuel efficient options.