Some cities have decided to make downtown look like downtown again. They are doing away with their pedestrian malls, bulldozing the kiosks, trees and benches that replaced streets 20 or 30 years ago. They are welcoming back the fumes and noises of once-banished traffic. And some that haven't decided to return to the downtown of an earlier time are thinking about it. It turns out, said Lawrence O. Houstoun Jr., that converting traditional shopping districts into a pedestrian malls worked _ but only for a while. Houstoun is an urban development consultant in Cranbury, N.J. Dry rot has set in again in many central cities, he said, because office buildings _ which provide many of the shoppers _ have been erected on cheap land too far away for a lunch-time shopping stroll. ``The pedestrian malls had some initial success because they were the first thing that looked good downtown, but they didn't deal with the basic problem,'' Houstoun said. ``The problem wasn't that people wanted to walk in the streets; the problem was that downtown wasn't convenient or became inconvenient.'' Houstoun said studies have established that at lunch time, people will walk for nine minutes _ or about three blocks _ from their office. If stores are a block or two further away, they will be shunned, no matter how pleasant the environment. So, a number of the 200 or so cities that took the plunge in the late 1960s and the 1970s have undone or down-scaled their malls or are considering it, Houstoun said. He reported his findings in Planning, the magazine of the American Planning Association, and elaborated in an interview. Kalamazoo, Mich., which called itself ``Mall City,'' is reopening two blocks of its four-block mall to traffic. Eugene, Ore. removed the kiosks, playgrounds, restrooms and plantings from two blocks of its pedestrian mall. New London, Conn. brought back the cars. Three Illinois cities _ Danville, Champaign and Rockford _ have given up their malls. Norfolk, Va. and St. Joseph, Mo. kept theirs, but in smaller configurations. In the capital of New Jersey, cars will return to part of Trenton Commons. Springfield, Mo. welcomed cars back to much of its mall, too. ``We drive around the square again,'' says Bob Turner, acting director of public works. But some cities find their mall still work well. The mall in Boulder, Colo., is a standout. And traffic-choked New York City is considering going the mall route by ``pedestrianizing'' 10 blocks of Broadway. A number of cities that would like to take out their pedestrian malls can't afford to, said Houstoun, a former official in the Departments of Commerce and Housing and Urban Development in Washington. Often the malls were built with federal grants; no federal money is available to undo them. Houstoun said it can cost $500,000 to $750,000 a block to take out the ``pedestrian features'' that give urban malls their character. The old, urbane, upper-middle-class Chicago suburb of Oak Park, Ill., spent $3.1 million in 1988 to take out a mall that had been built 16 years earlier for $1.4 million. In the process, 84 quarter-of-a-century-old pin oak trees were removed. Those that could be saved were replanted elsewhere in the community of 55,000. But ``it absolutely was not a mistake,'' to build Oak Park Mall in the first place, said Christine Burdick, executive director of Downtown Oak Park. ``It helped stabilize what in 1972 had been a declining retail center and helped us maintain a viable retail business,'' she said. ``It worked, it just became obsolete.'' Adds village manager Neil Nielson: ``It served a life, like anything else.'' Most Oak Park residents liked their mall, no matter what merchants felt. At the very time that streets, curbs, sewers and lighting were being reinstalled, citizens voted 13,000 to 9,273 in a non-binding initiative against tearing out the mall. What happened was five department stores that had been mall ``anchors'' either went bankrupt or moved away, and business fell off, Mrs. Burdick said. ``Restreeting'' _ her term for it _ has helped business, Mrs. Burdick said. Sales for the last quarter of 1989 were up 24 percent over the previous year; 15 new retailers moved in. The occupancy rate inched up from 75 to 80 percent. In its dependence on anchors, Oak Park Mall more closely resembled on-the-highway regional shopping malls than do most downtown malls. Downtown malls, said Houstoun, typically rely on two different types of shoppers _ lower-income city residents and office workers _ whose wants are not alike, adding to the malls' difficulty in finding a market. Office workers are important shoppers. One study found that they spend an average of $1,800 a year downtown on food and goods, most of it during the lunch break. In retrospect, said Houstoun, cities might have been wiser to clear abandoned buildings from core areas, making sites available for office buildings that would have provided the customers for downtown stores. The pedestrian mall, he said, ``wasn't a remedy geared to the problem and removing them is not a cure for today's problems, either.''