A new study by the National Highway Traffic Safety Administration says alcohol now is involved in roughly 55 percent of all fatal traffic accidents.

Annual statistics, according to the NHTSA report, "Alcohol Involvement in Traffic Accidents":

* 24,000 to 27,000 people are killed each year in accidents involving alcohol.

* 700,000 people are injured in accidents involving alcohol.

* 2 million motor vehicle accidents involve alcohol.

Runzheimer and Co., Inc., a Wisconsin-based management consulting firm, says only 6 percent of 1,400 gasoline stations surveyed are offering gasoline/alcohol blends, a percentage they say is sure to increase.

"Of even more interest," notes the survey, "is the fact that 53 percent of the queried station attendants themselves didn't know whether their gasoline was enhanced" with any form of alcohol.

Another kind of enhancement: Drivers in the Philippines are being urged to use a blend of diesel fuel and coconut oil in their diesel-powered vehicles. The Philippine Energy Ministry projects potential savings at $19 million.

For per-mile savings here in the United States (where an extra nickel-a-gallon tax became effective April 1):

* Keep your car properly tuned. Out-of-tune cars can cost you 3 to 9 percent in lost miles-per-gallon.

* If you weighted your car's trunk with bags of sand or gravel for added traction last winter, take them out. Fuel economy of an average car drops by 1 percent for every extra 100 pounds of weight.

* Keep your front wheels aligned and maintain proper tire pressure. In addition to being less safe to operate, your car's fuel economy can drop by as much as 2 percent for every pound of pressure below the recommended level.

* Drive smoothly. Hot-rodding, quick stops and starts, speed-up-slow-down driving can cost you in fuel economy and extra wear and tear on your car.

Energy Forum of Seabrook, Md., has come out with a "fuel conservation feedback device" it claims will help drivers improve their driving technique and help conserve fuel at the same time.

The device, named the Gastell, monitors the air going into a carburetor to be mixed with the gasoline being pumped in. When an inadequate amount of air is mixed with the gas, not all the fuel is atomized and the unburned gas passes through the engine's exhaust system. The lower the intake manifold vacuum (and the larger the amount of air taken in), the higher the car's miles per gallon.

Energy Forum president Michael Foster says the Gastell automatically signals the driver--with a red light and audible tone--when the fuel-to-air ratio drops below the optimum level.

The Gastell received a favorable rating in a Department of Energy report on such devices last summer. "The Gastell," it said, "can be a very effective aid to fuel conservation when it is correctly adjusted and installed in a motor vehicle."

One test vehicle driven for 1,254 miles showed "an improvement of 5.7 percent . . . realized over gas mileage recorded for the previous 991 miles."

"And that," adds Foster, "was with an expert driver behind the wheel."

The Gastell, with a switch for the audible tone, sells for $29.95; without the switch, $27.95.

A tip from "Shifting Gears," a newsletter put out by Executive Leasing of Beltsville: If the OIL or WATER light on your instrument panel goes on:

* "If the OIL light comes on, it's so serious you should pull to the side of the road and shut off the engine as quickly as possible. Under no circumstances continue driving, nor should you start the engine without expert help."

* If the WATER light comes on, it's not as potentially damaging, but still serious. Check your owner's manual to see if you could turn on your heater since this acts as a second radiator."