Insuring an automobile in New Jersey is not cheap — the state is ranked the third most expensive in the country by one industry measure.

But depending on where you live in South Jersey, your car insurance premiums may be among the highest or lowest in the state.

This is according to an analysis at Online Auto Insurance, a California-based company whose website ranked 49 territories using nearly 29,000 quotes of 65 insurers provided by the New Jersey Department of Banking and Insurance.

An Atlantic City territory ranked ninth most expensive, an average of $2,678 for quotes involving multiple profiles — including single men and women and married couples of varying ages.

A territory of Cape May County was among the cheapest — 41 out of 49, for an average of $1,690, Online Auto Insurance’s website says.

A region of mostly Cumberland County and another region of most of Atlantic County were near the middle — at $1,976 and $2,144, respectively.

The state average was pegged at $2,130.

This analysis is higher than one by the National Association of Insurance Commissioners, whose 2009-10 report placed the state average at $1,276 for combined average premiums involving liability, collision and comprehensive insurance. Louisiana and Washington, D.C., were higher.

Marshall McKnight, a spokesman for the state Department of Banking and Insurance, which regulates the industry, said multiple other factors go into ratings — type of coverage, driving record, age, the type of automobile, safety features such as airbags, etc.

“Now there are more sophisticated rating factors, and the result of that has been to place much less emphasis on territorial rating,” he said.

“Territory is still based on loss experience in that region — where that car is principally involved.”

Eric Stenson, a spokesman for New Jersey Manufacturers Insurance, which insures more than 800,000 vehicles, said vehicles in densely populated territories cost more to insure.

“(It) leads to a high rate of accidents, everything just gets multiplied,” he said.

Regardless of where one lives in New Jersey, many auto insurance companies are raising rates this year.

Nearly half of the state’s 71 active insurance companies have increased rates or will do so later this year, according to data from the Department of Banking and Insurance.

The rate increases range from less than 2 percent to 7 percent and higher. Driving much of this are personal injury protection and medical costs, McKnight said.

For example, New Jersey Manufacturers, which has an office in Hammonton, had a 4.93 percent rate increase approved.

“For us, it’s almost all medical costs,” Stenson said. “That’s definitely the biggest factor. Personal injury protection in recent years is definitely the lion’s share of it.”

Kristie McCarthy, a licensed insurance agent with Schick Insurance Agency in North Cape May, Lower Township, which covers New Jersey and Pennsylvania, said Hurricane Sandy is starting to have an impact.

“There are a lot of claims because of storms. Obviously, the more claims there are, the more expensive premiums get. Since Sandy, insurance has gone up. People’s cars got destroyed, so everyone has to pay for that in their premiums,” she said.

There are 71 active insurance companies in New Jersey, accounting for nearly $6.5 billion in written premiums, according to state data.

The five largest are New Jersey Manufacturers, GEICO, Allstate, State Farm and Liberty Mutual, which combined account for more than half of all exposures.

McKnight said reforms in 2003 helped bring more insurers to New Jersey.

The competition has helped control prices, although New Jersey auto insurance has been — and will remain — comparatively expensive to other states, he said.

“We’re always going to be up there because we’re the most densely populated state in the nation,” McKnight said. “We have more loss experience than other states because we’re in an urban area near Philadelphia and New York. Those are all factors that play a role in our rates.”

Contact Brian Ianieri:

609-272-7253

More than 30 years’ experience reporting and editing for newspapers and magazines in Illinois, Colorado, Texas and New Jersey and 1985 winner of the Texas Daily Newspaper Association’s John Murphy Award for copy editing.