District Liners were appalled by the spectacular accident on Route I-95 in which three people died after a bus crashed into their car and an explosion and fire ensued.

One of our newsmen was physically ill when he returned from the scene. He couldn't get that gruesome picture out of his mind.

It would be best to put aside questions about the how-and-why of that specific accident until an official investigation is completed. But Joseph S. Beck of Silver Spring raises a general question about highway driving that is worth some thought.

Motorists who obey speed limits are aware that some truck drivers engage in the dangerous practice of closing in at a rapid pace on passenger cars ahead of them. Some truckers seem to be deliberately trying to frighten or intimidate the drivers of pleasure cars by moving to within a few feet of them. One who looks into his rearview mirror gets the impression the truck is pushing against his rear bumper.

Beck's estimate is that some truckers have followed as close as 5 feet behind his car. At 55 miles an hour, that can really be intimidating -- especially to a driver who is aware that when a vehicle is struck from behind, its gas tank may rupture, causing an explosion that will engulf his car in flame. Beck asks, "What can be done about this?"

Readers of this column have tried to deal with that question over the years. A review may be in order.

There has always been a clear consensus among District Liners that there is need for more vigorous law enforcement. I agree wholeheartedly.

If there is a state, county, city or village that does not have a regulation prohibiting "following too close," I have not heard of it. In the District of Columbia, Section 33 of the Motor Vehicle Regulations words it this way:

"The driver of a vehicle shall not follow another vehicle more closely than is reasonable and prudent, having due regard for the speed of such vehicles and the traffic upon, and the condition of the highway." It is the kind of rule we shouldn't need. If there were no law, common sense would tell us to do the same thing.

Safety experts have for decades advocated a rule of thumb designed to tell us how many car lengths constitute a "reasonable and prudent" safety margin at various speeds. The average driver remains unaware of the rule and the arithmetic involved in it, and perhaps for good reason.

These days, one who tries to leave five car lengths between his vehicle and the one ahead of him on a beltway or highway is likely to find that an impatient driver has scooted into the void ahead of him. If he falls back another five car lengths to remain safely behind the interloper, another lane changer will dart into the space. After a while, the average driver realizes that the rule of thumb is impractical in modern traffic. He just concentrates on trying to be a survivor.

Policemen are pragmatic. If you hit somebody from behind, you're the one they ticket. The burden of proof is upon you, regardless of what the numbers were. The same pragmatism prevails in damage suits and criminal actions that grow out of traffic collisions. If you couldn't stop in time, you must have been "following too close." It is not an illogical assumption.

Although readers agree that more and better enforcement is needed, they do not agree on what is the wisest course for a driver who sees a huge truck apparently attempting to drive straight up his tailpipe.

Some have advised, "Move to the right lane and let him pass," but I do not consider that an adequate answer. When the right lane is open, I am already in it, driving at 55 miles an hour. I don't want to be bullied into moving over to the shoulder. I refuse to exceed the legal limit. And it is somewhat irrational for me to move to the lane on my left at a time when it is obvious that I am the slower of the two vehicles.

So my usual procedure is to maintain my pace for a while and hope the truck passes me. If that doesn't work and the truck remains close behind, I begin touching my brakes in the hope that red brake lights will alert the impatient fellow behind me to the dangerous situation he is creating.

When all else fails, I decelerate gently until I can safely pull over to the shoulder and let the trucker pass. I know this is not a good solution, but thus far it has kept me in the ranks of the survivors -- and that's more than can be said for the 50,000 people who die on American highways each year. t