How does a car insurance company know how often I use my car?

I know that the less I use my car, the less the car company will cost me. But how can they know how often I use my car?

If I buy car insurance claiming that I always use public transportation to work, will they believe it?

They will believe you until you get into a serious accident (not just a fender bender) That's when they check everything. And if they think you've been fibbing, they may not pay for anything.

They'll believe it until you report a crash in the middle of weekday rush hour; then they may check it out to see if you were truthful. They may also ask you for specific mileage at renewal time.

There is nothing for them to believe.. do you want to be driving into work? Because if you tell them you'll be getting the bus you won't be insured to drive to work.

Or am I missing something.

You are better of comparing different insurance companies to get the best rate. You can check out

http://compare-car-insurance-rates.mobi if you want

They may check the milage on your car and depending what season it is.