Gas prices are down by a third from a year ago, but the costs of owning a car may be heading up, courtesy of your auto insurance. After two years of staying flat, rates rose an average of 2.5 percent in 2008 and could rise up to 7 percent this year the biggest increase in more than five years, according to brokerage firm Stifel Nicolaus. Some tips to avoid the jump:

Insurance companies may refuse to budge if you ask for a rate rollback. But there s always room to bargain, says Michael McRaith, director of Illinois s insurance division. One thing your underwriter might do is apply new discounts. Some carriers offer discounts for professional degrees even a master s in education may qualify while others may apply a persistency credit just for being a longtime customer. If you ve started working from home or get laid off, let your insurer know you re no longer commuting by car. You could save up to 10 percent, for example, if you now drive less than 10 miles a day.

Tweak your policy

Most experts don t advise going with your state s minimum liability coverage, since a lawsuit over a severe bodily injury could then wipe out your net worth. But opting for a higher collision deductible from $500 on a typical policy to $1,000 could knock 5 percent off the premium on that line of the policy, analysts say. Most consumers file claims only once every eight to 10 years, so you ll probably come out ahead in the long run, says Jeanne Salvatore, senior vice president at the Insurance Information Institute. Bundling your auto and home insurance with the same carrier could shave a few bucks too, as could trading in your car for one that s less costly to insure.

Get smarter about credit

Underwriters use a credit-based score to help calculate your premium and if you have a few black marks on your record, you ll probably get hit hardest. Paying overdue bills and fixing errors on your credit report are good places to start. Using less of your available credit can hike your score too, according to Fair Isaac, the big credit-scoring firm. Insurers such as State Farm may also give you a break for a hardship such as a job loss, divorce or identity theft. Only certain hardships qualify, and only if they negatively affect your score. But you won t get a break if you don t ask.