PLANNERS know that stimulating residential development is a way to revitalize declining urban centers. Witness Baltimore's recent proposal to turn the fanciful Bromo-Seltzer Tower near Camden Yards into apartments. Indeed, at many locations, city developers are responding enthusiastically to the call for residential conversions.

But officials haven't had much success coaxing a similar housing revival in Towson.

Towson, a so-called "edge city" by virtue of its concentrated office space and major retail, is not in decline, but county officials have long-range concerns.

Filling commercial vacancies has been hit-and-miss. It took more than a decade to find a redeveloper for the empty Hutzler's store at York and Joppa roads. A block south, the architecturally dramatic Towson Commons has struggled for years to fill its food court and street-level shops despite a successful multiplex cinema.

Towson is experiencing an influx of investment in shops, cafes and restaurants. There's a lot of foot traffic during office hours, but it becomes a ghost town at night when workers head home.

A few high-density residential buildings, officials believe, would help keep people shopping and dining in the county seat after 5 p.m.

Despite encouragement from such community groups as the Towson Partnership and added flexibility in zoning to encourage apartment construction, the market has been slow to respond. Zoning in some sections of Towson allows buildings seven stories or taller, the most intense residential use the county permits.

Towson's core is dotted with underused, marginal properties. Transforming them into residences would inject life into the closest thing the suburbs offer to a pedestrian-friendly downtown. It would also sustain Towson's commercial renaissance. Developers should examine the possibilities.