Central Park auto traffic lightened this week as city officials closed parts of the east and west drives to countercyclical rush hour traffic.

The west drive runs southbound from West 110th Street, gentrified to Central Park North, which turns into Cathedral Parkway at the park’s northwest corner, officially Frederick Douglass Circle. For a six-month trial ending in November, west drive will be open mornings, and closed evenings north of 72nd street.

Similarly, east drive, which runs north from the Avenue of the Americas and Central Park South (One Sixth Avenue and 59th Street, respectively) to Malcolm X Boulevard – Lenox Avenue at Central Park North, will be closed north of 72nd Street during morning rush hours. Traffic is heaviest on west drive after sunrise, and east drive at eventide.

These changes are the latest in a series of twists and turns since the decision in 1966 by Mayor Lindsay and Parks Commissioner Thomas Hoving to close all Central Park drives on weekends. As executive director of the Parks Department in that prehistoric year, I oversaw enforcement of the new rules, which barred all traffic from Friday evening until Monday morning.

Since then, a succession of changes has reduced automobile traffic in the park by blocking certain entrances and exits, closing the park drives overnight, and banning midday traffic, except for the 59/6 to 72/5 leg of east drive. High Occupancy Vehicle rules have been imposed, requiring a passenger as well as a driver before a car is allowed in the park.

An insistent campaign by a variety of organizations has demanded complete closing, relying on anti-car sentiment. When we tried minor alterations to the schedule that generally benefited pedestrians and park users, we received a blitz of negative emails clearly generated by a pressure group. We abandoned the proposals because they were not worth the controversy.

Even now, Transportation Alternatives could proceed through lawsuits and City Council legislation to attempt to overrule the mayor’s decision, although he has further limited cars in the park. This is part of New York’s political jungle: When you lose in one forum, you try another, and the case goes on until one side or the other runs out of money for lobbyists or lawyers.

The mayor has refused to enforce some laws passed by the City Council on the ground that the city’s lawyer, the Corporation Counsel, considers them unconstitutional or ultra vires. The state courts recently upheld his right to do that, even if there has been no judicial determination of unconstitutionality.

The City Charter is an imperfect document. One of its limitations is that it does not specify with clarity the separation of powers between the legislative and executive. When they collide, it is the judiciary that must resolve the tangle. Since New York State has three levels of courts, it often takes more than a year to get a final answer on a question, unless it is marked urgent.

The Central Park drives were built under the original “Greensward” plan, prepared by Frederick Law Olmsted and Calvert Vaux. They were built in the 1860s for horses and carriages, predating the automobile by 40 years. These drives are at grade and designed to be totally separate from four depressed transverse roadways that cross the park at 66th, 79th, 86th, and 96th Streets. The vistas of the park are unmarred by the transverse roadways, which are open to motor vehicles day and night.

In the late 1890s, the commissioners of Central Park routinely denied permission to automobilists, as they were called then, who wished to use their horseless carriages on the drives. The Automobile Club of America sent drivers into the park to be arrested, so that a judge could decide the issue. The judge ruled that cars were “pleasure carriages” and thus allowed by existing park rules. The first permit granted, in 1899, was for an “electric automobile runabout.”

That was also the year of the first traffic fatality in America. On September 13, one Henry Hale Bliss alit from a streetcar at Central Park West and 74th Street when a passing electric taxicab struck him, crushing his head and chest. A plaque on the park wall commemorates this sad event. In recent years, bicycle fatalities in the park have far exceeded car deaths.

These events are described gracefully by Professor Witold Rybczynski in his illuminating book, “A Clearing in the Distance.” The motor car and the horse co-existed competitively for some 20 years, until the car emerged as the predominant vehicle for park users, as well as commuters using the drives to get to work and to return home.

Although banning automobile traffic in Central Park would be pleasant from a park point of view, it would be disastrous for neighborhoods on both the East and West Sides of Manhattan. The cars prohibited from using the park at rush hour would not simply disappear; their drivers would use alternate routes, going south on Columbus and Fifth Avenues, north on Amsterdam and Madison Avenues, and both ways on Central Park West and Park Avenues.

These residential avenues, already crowded with rush hour traffic of cars, cabs, buses, and taxis, would be overwhelmed by the additional traffic generated by closing the drives at their hours of maximum use. The park now functions as a safety valve, relieving the pressure of traffic only at peak hours for each direction.

This is a reasonable form of time-sharing. Living in a large and crowded city, we all must accommodate each other, accepting reasonable restraints on our own comfort.

We agree with the majority of Transportation Alternatives’ initiatives, and believe the group is of significant value to New York. But on this issue we dissent from the politically correct:

So far, the anti-car ideologues have not accepted any kind of compromise on cars in the park. Their hatred of the automobile, as a symbol of the machine age, as a consumer of gasoline and oil, as a legacy of Robert Moses, as a dangerous, noisome, odiferous, and obnoxious juggernaut, is unrequited by the city’s efforts to reduce traffic and preserve residential neighborhoods at the same time. Either this antipathy to automobiles will not stop some protesters from driving their SUVs to the Hamptons each weekend. But that’s all right as long as people with jobs don’t use the park to get to work.

Mr. Stern is a former New York City Parks Commissioner and the founder of New York Civic.