The Internal Revenue Service raised the standard mileage rates for use of a car to 50.5 cents

per business mile driven. Set to take effect on Jan. 1, 2008, the new rate compares to the current rate of 48.5 cents. The increase "reflects a combination of factors, including higher fuel prices, rising insurance costs and higher depreciation costs," according to Runzheimer International, which conducted a cost study for the IRS. The standard rate is used to calculate the deductible costs of operating an automobile for business.