With a City Council vote Thursday on landmark zoning legislation, Philadelphia will have a promising new blueprint for growth in the coming decades.

The expected approval of a complete rewrite of the zoning code is years overdue. But Council - which itself got the ball rolling in 2006 - is responding to a clear directive from city voters.

It was voters who decided in a 2007 referendum that the nearly 50-year-old zoning rules finally had to be revamped.

Indeed, there's little doubt the city has been held back by a zoning playbook that's so arcane and outdated that nearly every other project requires a zoning variance. That process is time-consuming and costly, and the uncertainty surrounding city approvals convinces many outside developers and investors unfamiliar with the labyrinthine ways of City Hall that it's just easier to steer clear. As a result, the city loses potential new players whose ideas could move it forward.

It's certainly time to move ahead by enacting the zoning rules given tentative Council approval last week. They're the result of an impressive, four-year effort by a citizens' commission that included Council delegates and other appointees.

Several months ago, there was talk in Council that the process was moving too quickly. But delaying approval into next year risks setting the process back years, since Council will get six new members. So the perseverance of the commission under Deputy Mayor Alan Greenberger, and Council members like Bill Green, Brian O'Neill, Frank DiCicco, and Jim Kenney, in working out concerns proved crucial.

In an odd way, Council further illustrated the need for reform by its own vote this month on a misguided zoning change. The measure, pushed by a proponent of zoning reform, DiCicco, on grounds of promoting business would permit a massive wall-wrap ad on a building within sight of the billboard-restricted Vine Street corridor.

That threatens federal highway funds under anti-blight rules, but it's not the sole reason Nutter this week announced his veto. He also said the bill was "a very, very bad example of, in essence, spot zoning" - exactly the ill that the new code hopes to cure.

The wall-wrap dispute highlights the fact that Council still will have authority to craft special rules. But with a better zoning blueprint, that should be rarely if ever needed.