Commuters whose daily travels take them within a block or two of 14th Street and Pennsylvania Avenue NW must have looked long and hard at the two maps of that area that appeared in early editions of our Metro section on Monday.

One map showed a temporary plan for rerouting traffic during construction work; the other showed the permanent plan that will be in effect after the construction work is finished.

If you found those changes puzzling, let me tell you about another one that may have an even greater impact on your daily life. Some two months from now, 13th Street will no longer be a reversible one-way artery during peak hours.

That decision was made by the District's Department of Transportation many months ago and was published in the D.C. Register on Aug. 31.

It remained one of the best-kept secrets in Washington as the District conducted surveys during September, budgeted money for street signs and markings, and completed its plans for traffic signal modifications and new lane lines. A mailing list was compiled for direct mailings designed to explain the new plan to those most likely to use 13th Street during the morning and evening rush hours.

A review of public comments on the plan was not scheduled until October. In other words, the District began with a rather firm decision to make the change, and then scheduled an 11th-hour "review" of public comments on it.

Most people didn't know about the plan and therefore had no occasion to comment.

Some of the objectives of the plan can be considered laudable. By keeping 13th Street a two-way roadway at all times, its carrying capacity will be diminished, thereby causing vehicles to move so slowly that many motorists will begin using mass transit and leaving their cars at home. There will be less noise and fewer exhaust fumes along 13th Street, making it a more pleasant place for people who live along that corridor. Parking problems will also be alleviated for residents, who will no longer have to get their parked cars off 13th Street twice a day.

However, some of the consequences of the change will not be so laudable. Traffic engineers have long held that one-way streets are safer than two-way streets for both motorists and pedestrians. Head-on collisions are virtually eliminated, and pedestrians face danger from only one direction.

In addition, traffic engineers recognize that parked cars are a major factor in pedestrian deaths, particularly in the deaths of children who dart out from between parked cars that have blocked from their sight the imminent danger of moving traffic. The new plan for 13th Street will permit parking on one side of the street during the morning traffic peak and permit parking on the other side during the evening peak.

This will reduce the rush-hour flow from four (or three) lanes to two, and will provide one lane for movement in the opposite direction.

The new plan will undoubtedly cause some commuters to switch to mass transit. But it also seems likely that people who are not well served by the present transit system will continue to drive. Either they will endure the slower pace of 13th Street or they will add to the crowding on alternative routes that suit their needs.

The D.C. Citizens Traffic Board heard about the new plan for 13th Street only after the Transportation Department had made up its mind to make the change. The board has grave doubts about the wisdom of eliminating the reversible one-way scheme.

Joseph V. Osterman, who retired from the Metropolitan Police Department with the rank of Deputy Chief of Police in charge of the Traffic Division, scoffs at the Transportation Department's contention that a one-way pattern "encourages high speeds that are difficult to restrain."

Joe was a no-nonsense cop who assigned a scout car to move along 13th Street during each rush hour at precisely the speed limit. Nobody passed that scout car, so everybody had to obey the speed limit. It was as easy as that. Daniel J. Hanson, who served as deputy director for traffic engineering in our Highway Department, points out that it is a simple matter to regulate speed on a one-way street by adjusting the timing of its traffic signals.

Nevertheless, our Transportation Department has decided to restore the "neighborhood amenities" of 13th Street, starting on Jan. 7. This leaves everybody who drives with these questions: Will the same deference to neighborhood amenities be applied to 16th Street and to Connecticut Avenue and to every other major commuter route? Will these changes also take place before our master plan for mass transit is completed? How will people cope meanwhile?

I don't know the answers, but I thought you'd like to know what is in the works.