Sid Highfill, 44, is lead instructor for the automatic transmission class at UTI Mooresville/NASCAR Technical Institute (NTI) in Mooresville, N.C. This bumper-to-bumper auto expert worked for Mercedes-Benz and Chrysler before joining the faculty two years ago.

He offers tips on how to keep your vehicle running safely and efficiently. The most important things:

"Tire pressure and tire-tread depth are real safety factors. If the pressure is not up to where it should be, the tire pattern — the 'footprint' on the road — will not be correct and can make your car handle poorly. And if the tread is incorrect or worn and you hit a rainstorm, your car can hydroplane.

"You can easily check your own tire pressure at a filling station. A mechanic can check the depth of your tire treads, but you can use a penny as a rule of thumb: If you put the penny into the tread and can still see the top of Abraham Lincoln's head, the tread is too thin and you should get a new tire.

"For economy and safety, change the oil and change the air filter. If you have some mechanical ability, you can change the oil at home. But there are so many quickie places that will do this for you for $20 or so. Just watch the ads for deals. They can also top off your fluids, add antifreeze and lubricants.

"Definitely have your brakes checked. You can have this done when you have your oil checked."

About those fluids:

"Engine oil, transmission fluid and coolant. If you're too low on any of them, it can cause drastic failures and can strand you if something goes awry. If engine oil is too low, it can damage your motor. Too-low transmission fluid can make your tranny slip. If you're low on coolant, your engine can overheat.

"What is most overlooked by the owner of the vehicle? Probably the most overlooked would be the engine-oil level. If your car is new enough, it will have an oil-level gauge. If you stay on top of things and get your car regularly serviced by a mechanic, this will not be a problem.

"People don't think the level goes down significantly and rely on a warning light to alert them. But the light will only go on when levels are too low — and by then, some damage probably has already been done.

"Rule of thumb: After driving 3,000 miles, you're probably well over a quart low." And don't forget ...

"Air filters are easy for anybody to change and should normally be changed at least every 30,000 miles — more often if you drive on dirt roads. A dirty air filter decreases fuel mileage and makes it easier for particles to get into your engine ...

"Windshield wipers. People don't tend to notice they've gone bad until they need to use them. If you have bad wipers and hit a rainstorm, that's pretty unsafe.

"About your exterior lights. Before you leave on your trip, do a good walk-around to make sure those lights are in good working order."

Trouble on the highway:

"If a tire goes flat, you can still drive your car out of harm's way. Driving a short distance shouldn't hurt the wheel rim. Get off busy highways as soon as possible.

"If the oil light goes on, you definitely want to get off the road as soon as possible. Get to a gas station and have it checked."