If you've been following the news, you might expect to pay more in taxes when you go to the store today for your weekend shopping expedition.

After all, you have heard that the Honolulu City Council approved a tax increase that raises the all-pervasive 4 percent excise tax to 4.5 percent.

But wait a minute. First, the new tax has to be signed into law by Mayor Mufi Hannemann, which admittedly is a done deal.

But even then, it will not go into effect until Jan 1, 2007.

By that time, presumably, city officials will have come up with some kind of transit project on which it can spend the $150 million a year the new tax is expected to generate.

And a transit project is the specific and focused purpose of this new tax. The state law that authorized it restricts its use to a new transit start, of one kind or another.

It is fairly clear that city officials have their eyes on something much like what was planned in the early 1990s: A high-tech rail system of some kind that links booming West O'ahu with downtown, Waikiki and the University of Hawai'i.

But that's not an entirely done deal. Technology has changed over the past decade and a half. Honolulu has grown. Public expectations have changed. So what finally emerges may not be what was on the table before.

Hannemann announced last week that he will demand a full-court press to come up with a preferred and completed transit plan by the date the new tax kicks in. That makes good political sense.

The public is not likely to accept paying more taxes on their groceries if the transit alternative remains a pie-in-the-sky dream.

The danger ahead is that Honolulu may start taxing and building without any clear, long-term vision of where it intends to end up.

Point A: Hannemann frankly admits that what the city is likely to start building is far from a complete system. There is not enough money nor enough planning time to get going on a complete system by the projected Jan. 1, 2007, start date.

Rather, it will be a chunk of some kind of transit line, serving one portion of West O'ahu to another. In short, it will be a start, not a finish.

Point B: The money raised by the transit tax plus whatever Uncle Sam puts into the pot will likely be far short of what is ultimately needed. If you want evidence, consider that city officials originally asked for a full one percentage point increase in the excise tax as the amount needed to raise the necessary local share of funds. In the end, they got half that.

It took a remarkable alignment of political stars to get ourselves to this point. It will take much more canny political alignment to get us to the next step: actually planning and selling the public on a transit system that will get us where we want to go at a price we can afford.

Jerry Burris is The Advertiser's editorial page editor.