TEC sells Volvo and Mack Trucks as well as Hino and Isuzu medium-duty trucks and GMC light-duty commercial trucks. It also has truck rental and leasing businesses, so, under the new tax bill, Thompson can also deduct 50% of the purchase price of new trucks he buys for that side of his firm.

Normally, depreciation write-offs are stretched over several tax years as a new asset deteriorates with age.

However, to help the manufacturing sector recover from the recession, a bonus depreciation program was created in 2010. Under it, in the 2011 tax year, equipment buyers could write off 100% of their purchase cost that year.

In 2012, the write-off dropped to 50% of the purchase cost and the program was to expire at the end of that year.

But keeping the 50% write-off is expected to help spur truck sales this year because the tax break “takes some of the sting” out of the higher cost of more fuel-efficient trucks, said Richard Witcher, chairman of American Truck Dealers and CEO of Minuteman Trucks, a light- and medium-duty truck dealership in Walpole, Mass.