If you’re looking to boost your deductions — and reduce your 2016 tax bill — you may want to consider purchasing a business vehicle before year end. Business-related purchases of new or used vehicles may be eligible for Section 179 expensing, which allows you to immediately deduct, rather than depreciate over a period of years, some or all of the vehicle’s cost. But the size of your deduction will depend in part on the gross vehicle weight rating.