Q. I am about to buy a new car, and would like to know on what the sales tax is based. This particular vehicle will have a “destination charge” of $600. Since the dealership is charging this on all cars, I don’t have a problem paying it. But it seems to me that the sales tax I pay should not include this amount, or any “documentation fees” that are added. Can you help me with the answer to this question?

A. Sales tax is never charged on additional fees such as destination charges or documentation fees. Additional accessories that are part of the vehicle itself are subject to sales tax. Here’s the formula — take the total price of the vehicle, less any trade-in (which can only be passenger vehicle for passenger vehicle) and less any rebate from the manufacturer, and your sales tax will be 7 percent of the remainder.

What to do after buying older car

Q. I know a car newly registered must be inspected within 10 days. I plan on buying an older car and restoring it but it will take some time. I need to register it to park it in my driveway but it will be some time before it will be ready for inspection. Can I register this car without having it inspected?

A. There are several steps you should take with regard to this vehicle. First and foremost, you must pay the sales tax on the vehicle, even if you do not plan to register it immediately. You have, by law, until the 20th day of the month following the month of purchase to pay sales tax and avoid interest and penalty on the tax. For example, if the bill of sale is dated April 1, 2008, you have until May 20th to pay sales tax without interest and penalty. The penalty is a flat 10 percent of the sales tax amount, and then interest will accrue on that amount at the rate of .10 percent per month. Depending on the year and make of the car, if it’s deemed to be a car of particular interest, or if you must pay sales tax on the book value rather than the purchase price, these fees can mount up quickly. You can go to any one of the DMV branch offices (RI Mall Express excluded) to perform this transaction, but you must have your original bill of sale and proof of previous ownership by the seller, which can be an old registration, a property tax bill, or a sales and use tax form showing that the seller paid sales tax on the vehicle.

While you are restoring the vehicle, if it is kept in your garage or a commercial space, you are not required by the DMV to register the vehicle. If you did choose to register the vehicle and forgo inspection, the vehicle would then remain suspended in the computer system until an inspection report for that vehicle was completed. If you are concerned about having an unregistered vehicle on your property, you should contact your city or town’s zoning board to check what the regulations are regarding unregistered vehicles.

Gina Antonucci Zanni, supervisor of communications for the State Division of Motor Vehicles, has agreed to answer questions of general interest posed by Journal readers about state motor vehicle laws and procedures. To ask a question that would also be of interest to other readers, send a letter to Ask projoCars, Features Department, The Providence Journal, 75 Fountain St., Providence, RI, 02902. You can e-mail your question to projocars@projo.com. Please put “Ask projoCars” in the subject field. Questions or complaints of a specific nature should be posed to the DMV directly and will not be answered in this column.

CONFUSED about road rules? Or looking for a low-number license plate? You’ll find an archive of official answers to past driving questions posed by Journal readers at projocars.com