Some adventuresome folks still are occasionally driving convertibles with lowered tops. But it's high time to remember that warm weather is behind us and to make sure your car or truck is ready for winter.

Many vehicles that run in warm weather refuse to start or run acceptably when cold weather puts an extra strain on them. A late-model car in marginal shape might have started and run acceptably in summer because electronic controls adjusted for its deteriorating condition. In winter, that car probably won't start or will stall or run poorly enough to convince even an average motorist that something is wrong.

It never used to be that way. Older cars weren't as efficient as newer ones, but they had carburetors and such things as old-style ignition systems that gave clear early warnings when things began to go wrong with them. They cried out for a "tune-up."

Late-model cars no longer require tune-ups, but they DO call for manufacturer-recommended routine maintenance to run well and deliver decent fuel economy. Unfortunately, such maintenance is easily put off. So now is the time to check the car's owner's manual to see what maintenance is needed.

To make things easier, here's what to check to keep your car or truck operating efficiently and safely through winter.

Battery: The colder it gets, the harder it works to start a vehicle. Tighten battery cables and remove debris buildup from terminal posts.

Belts and hoses: Cold weather causes them to fail more quickly. Look for leaks, cracks, fraying, bulges or loose clamps. These parts wear more rapidly in modern vehicles because of higher under-hood temperatures.

Body: Wax it and wash it at least once a month, with special attention paid to removing salt and road gunk from the underside. Garaging goes a long way toward keeping it looking good.

Brakes: All brake-system parts should be checked. Make sure you know how to correctly use the anti-lock brake system because it probably will be used more often on slippery winter roads.

Cooling system: Check for coolant-system leaks. Replace old coolant, which probably has lost the right amount of cooling-system rust inhibitors.

Electrical system: Especially check the alternator and voltage regulator.

Engine: Does it start quickly, accelerate smoothly and get good fuel economy? Check the owner's manual to find out what should be done at specific mileage or time intervals to keep it humming. Drive regularly. A vehicle that sits for a long time can cause expensive problems, especially in winter.

Exhaust system: Make sure all components, such as clamps, are tight. This system takes an extra beating in winter because of such things as jarring potholes and contact with roads that have high accumulations of snow and ice. The additional wear can cause dangerous exhaust-system leaks.

Gasoline tank: Keep it at least half full to prevent gas-line freeze, which can prevent a vehicle from starting. Fuel additives can keep gasoline from becoming stale if a car or truck isn't driven much.

Interior: Air out rubber floor mats, which get especially wet in winter. Wet mats can damage carpets and lead to floor rust -- and subsequent holes in the floor.

Lights: Make sure all work, including the emergency flashers, back-up, interior and trunk lights.

Oil: Ignore what a friend or neighbor says -- check the owner's manual to determine the correct oil to use in cold weather for easier starting and less engine wear.

Spark plugs: Some plugs said to be good for 70,000 or so miles lose much effectiveness at 40,000-50,000 miles and cause performance and fuel economy loses.

Tires: Good traction on snow and ice calls for correct inflation. Don't forget the spare, which should be accompanied by a jack in good condition. Winter tires with added traction are superior to all-season tires.

Transmission: The level and condition of its fluid should be checked. Many drivers get stuck in the snow with their vehicle, and getting it moving puts lots of strain on a transmission.

Trunk: It should contain a snow brush and ice scraper -- along with a flashlight, jumper cables, gloves, boots, roadside reflectors and/or flares and traction mats and/or tire chains. Put them in a gym bag to make them easy to find quickly.

Wipers and washers: Wiper blades more than six months old should be replaced because they've taken a beating from summer sun and dirty air. There's less daylight in winter, and road salt covers windshields and headlights. The washer system also should work properly. Carry an extra container of washer fluid in your vehicle and leave another container in the garage because it can be used up quickly in winter.

Finally, a cell phone can let a driver quickly summon help.