Next to buying a house, your car is probably the most expensive purchase you'll make in your lifetime. The spend doesn't end when you drive off the lot, either. You have regular maintenance bills to pay and the responsibility to keep gas in the tank, and that doesn't account for more serious issues down the road.

What if you could save a few dollars here and there when you drove your car? It's not such an outlandish idea, and with the amount of driving many Americans do, those dollars add up. Here are a few tips to save money when you're on the road.

Turn Off Your Engine

The best way to save on the cost of driving would be "don't drive at all." Since we assume that's not an option, you can still benefit by using the logic of, "a car that's not running is a cheaper car." Instead of giving your car five minutes to warm up, take advantage of modern technology on a cold day and set off shortly after starting the engine. Turn your engine off when you wait for someone to run into the store for a drink, or invest in a car with start/stop technology.

Check Your Tire Pressure

Here's a popular trick from the trucking industry that you can use to save some money. When your tires carry too much air or are under-inflated, you blow cash right out your tailpipe.

A more inflated tire typically offers less rolling resistance, which means less power is used to move you forward and therefore less fuel. At the same time, you need to make sure your tires are properly balanced to avoid uneven tire wear. Throwing away a tire with worn tread on just one side is a good way to rack up a serious bill on some new rubber - pay attention to your tires.

Buy Denser Gas

Don't buy that overpriced expanded stuff! Wait, how can I buy denser gas, you ask? Like many liquids, gasoline expands and contracts in correlation with the temperature. So if you buy fuel in the morning or evening when it's had time to get nice and cool - and dense - you get more for your money. Use apps to help you locate the lowest prices and then time your visits appropriately to maximize your savings!

Tune up Your Insurance

We're not saying you should go and drop all the important coverage that comes with your insurance policy. However, it does pay to review it every now and again. For example, if you could benefit from a group policy, but don't use one, you can combine your current policies to save money. Maybe you drive less these days, or perhaps you could receive a discount for a good driving record or even earning good grades in school.

Like so many things in life, the money we spend on driving creeps up over time because we tend to get lazy. Start paying attention to these things and saving a little every day, and you'll be on the right side of your budget soon enough, with the needle pointed squarely at "Full."

Scott Huntington is a writer from central Pennsylvania. He enjoys working on his home and garden with his wife and 2 kids. Follow him on Twitter @SMHuntington