Forty years ago, pedestrian malls became the rage across America. As cities tried to revitalize their downtowns to compete with fancy new suburban shopping malls, more than 200 cities and towns — including Sacramento — closed streets to traffic and parking, planted trees and installed fountains and benches to create pedestrian-friendly retail areas.

But pedestrians didn’t find them friendly after all. Most malls didn’t have a clear purpose or focus to attract new pedestrian traffic; they worked well only in areas already dominated by it.

Most became like Sacramento’s K Street Mall, between 7th and 12th streets: dingy, half-blighted areas where new businesses came and went and a few hardy souls managed to survive. Most have since disappeared, with cities as diverse as Chicago and Kalamazoo, Mich., bringing back auto traffic even as they keep wide sidewalks and other pedestrian amenities.

Now Sacramento city leaders are thinking of doing the same. In March, the City Council agreed to study options for opening the K Street Mall to vehicles. Earlier in the month the Council took another aggressive step in improving the mall when it hammered out an agreement to provide a $5.7 million subsidy to attract entertainment venues to buildings at 10th and K streets.

Now add the $4 million renovation of the K Street streetscape, which the city has just begun. It includes new entertainment venues such as Ella Restaurant and the Cosmopolitan restaurant, cabaret and club and the luxury apartments in the Cathedral Building. The combination may well add up to a successful formula for K Street Mall — and with it, a tipping point in the decades-long struggle to achieve a downtown revival.

 That will only be true, however, if we learn from past mistakes and experiments — our own and those of other cities as well. Sacramento’s design commission is looking at two successful models for re-jigging K Street Mall. One, called the Portland option, would have one-way car traffic that would share space with light-rail, as is currently the case on 12th Street. The other, called the San Jose option, would have one lane dedicated to one-way car traffic, another dedicated to light-rail.

Getting the physical configuration right is important; other factors are even more critical, say city planners who have helped to create revitalized downtown malls. Just bringing traffic back wasn’t a panacea for Chicago’s State Street Mall, for example. Businesses paid more in property taxes to support landscaping and marketing; the city contributed dollars for infrastructure improvements, which helped draw retailers to the area.

Downtown Denver’s 16th Street mall thrives on entertainment venues, with a collection of 200 restaurants, clubs and other businesses. Denver also has downtown housing that puts 10,000 residents within a few blocks of 16th Street.

Sacramento is a long way from that scenario, and yes, now is a difficult time for residential development. But city leaders must continue to look for every opportunity to create attractive, affordable urban living spaces. A significant downtown population is a critical missing factor in revitalizing the city as a whole.

Success will require time, money and creative energy from not only the city and its redevelopment agency, but also from property owners, merchants and civic institutions. I think we’re finally seeing that in recent decisions on the K Street Mall. We need to see much more of the same.