Rising oil prices are accelerating costs for paving projects in town – even those already completed.

LRM Industries Inc. is set to receive another $37,000 on its original $492,000 contract to repave streets in and adjacent to downtown Lawrence.

Lawrence city commissioners are expected to approve the payment Tuesday night as part of a change order triggered by rising prices for asphalt oil, a necessary ingredient in putting down new, smooth pavement along sections of Massachusetts, Seventh, New Jersey and Kentucky streets.

The rising costs actually added $48,731 to the contract, but other savings – by reducing the amount of material used, mostly – managed to cut some costs to below what had been expected.

“We had serious increase over the summer,” said Steven Lashley, a project engineer in the city’s Department of Public Works, who estimated the price increases at 10 percent to 12 percent. “It went the positive direction, on the contractor side. We had a severe increase.”

The extra payments are provided as contingencies in city contracts for repaving and other projects that require use of oil and oil-related products, the escalating prices of which had been fueling even larger rises in contractors’ bids on projects.

The contract provisions remove some fear of the unknown – how much prices might increase – from the equation for contractors, by assuring them that they won’t get stuck paying the difference if asphalt oil costs boost the price of pavement by, say, $10 a ton during the two months between when a bid is submitted and actual material is being applied to a street.

“It helps us get a better and more realistic bid price,” said Lashley, who noted that a decline in material costs would reduce costs for the city. “They’re not gambling on the future. : Otherwise, they would have to bid real, real high from the get-go. They would bet that the (asphalt oil) price would go way up.”

And high bids, Lashley said, could end up costing taxpayers more in the end.

Either way, the added costs won’t be expected to end anytime soon – at least for work completed this summer. The additional payment due to LRM is but the first of several that could be coming in during the coming months, as contractors settle accounts for other repaving projects in town.

And that means some additional work that had been anticipated later this year – replacing some crumbling concrete curbs and gutters along Harvard Road, Goldfield Street and other stretches nearby – may need to wait until next year, Lashley said.

“We’re going to be restricted on what we’ll be able to do elsewhere,” he said.