The index, which tracks all costs associated with owning and running 17 different models of car also reveals that rising fuel prices have increased the yearly fuel bill to £1,154, or £22.20 a week, an increase of 11% in six months.
However, the largest cost factor in all new cars remains depreciation, with the average person losing £1,987 a year, or more than £38 a week.
RAC technical director David Bizley said: "As the Christmas bills begin to land on the doormat, for many these figures will deliver as an unwelcome New Year message. Splashing out on Christmas often means that their thoughts turn to the cost of what's under the tree rather than on the driveway.
"It's not only Christmas that seems to cost more and more as rising fuel costs and growing depreciation mean bad news for motorists.
"The UK has the cheapest pre-tax fuel in the EU, but amongst the highest pump prices so the Chancellor's decision to freeze fuel duty will be welcome news for motorists, particularly as the cost of motoring continues to rise."
The only good news for motorists is the fall in quoted insurance premiums, finance and maintenance costs. Over the last six months:
The RAC Cost of Motoring Index looked at a sample of 17 different cars as at September 2005. The index is designed to help motorists understand how much their car really costs them in order to make informed decisions when buying a new or used car. It tracks all the costs associated with owning and running a car from the initial purchase to depreciation, the cost of insurance, fuel, servicing, VAT and breakdown cover.