No. 3: No coverage for injuries if you drink and drive

Thirty-seven states have alcohol-exclusion laws, which allow insurance companies to deny medical coverage for injuries due to intoxication, according to the Governors Highway Safety Association. That means that in those states your insurance company could refuse to pay for your medical treatment if you crashed and were injured while driving and impaired by alcohol or drugs.

No. 4: Coverage excluded for unlicensed drivers

Some policies exclude coverage if an unlicensed driver uses your vehicle and crashes. Bottom line: Be picky about who drives your car.

"It's awkward to ask to see your friend's driver's license, but, then again, you're trusting someone with your car, and if they wreck and there's no coverage, you're the one who's going to be responsible," Gusner says.

No. 5: Exclusions for doing business

Many policies exclude coverage for any business use of the vehicle, Wilson says. Borrowing someone else's car won't help, either -- that person's auto policy is unlikely to cover your business use.

In addition, many policies exclude coverage for pizza or other deliveries.

"Imagine how many pizza-delivery drivers are on the road tonight without insurance," Wilson says. "This exclusion could apply to all kinds of exposures, from delivery (of) newspapers to Mary Kay cosmetics."

No. 6: Restricted coverage for car theft

Some policies exclude coverage for theft without any evidence of forced entry, Wilson says, and some don't offer coverage for upgraded or custom equipment. That can be a problem if you've made some after-market modifications to your vehicle.

Wilson recommends working with an agent who understands your needs and can explain the differences among policies.

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