THE good news is that Seattle and the Puget Sound region are in the midst of an exciting time of progress toward mobility options for our future; the bad news is, on nearly every front, we've managed to underfund our visions.

From Tukwila to downtown Seattle, construction is under way on all 14 miles of Link Light Rail's initial segment, on schedule to open in 2009. Airport Link, the 1.5-mile connection to Sea-Tac Airport, is in design and affordable with existing tax dollars. Planning is under way on North Link (connecting downtown Seattle to the University of Washington and Northgate) and Sound Transit 2, the next phase of investments. Visions of a regional high-capacity transit network are coming into focus.

The initial segment is under budget, and existing funds may build more miles than originally thought. But who can forget that the original 21-mile line passed by voters in 1996 was badly underfunded?

The state Legislature recently passed a transportation package that includes partial funding for replacing the aging Alaskan Way Viaduct and Evergreen Point floating bridge. Visions of a safe, modern highway system are coming into focus.

But in order to fully fund these vital safety and mobility projects, the Regional Transportation Investment District (RTID) board must convince regional voters to pick up the several-billion-dollar difference by a state-imposed deadline of 2006. And a citizen initiative effort is under way to dismantle the state's gas-tax increase that will fund these improvements.

The Seattle City Council approved funding for the South Lake Union streetcar just as Seattle and King County announced a potential deal to save the waterfront streetcar by relocating the maintenance barn to Pioneer Square. Expansion possibilities include linking the two lines and extending them into strong ridership areas of the International District. Visions of a Seattle streetcar network are coming into focus.

But how will we pay for this expanded system without raiding operating money from Metro buses?

The Seattle Monorail Project recently announced that it had successfully concluded contract negotiations for building the Green Line. Visions of a multiline monorail network crossing our city seemed to be coming into focus — until the now-rejected finance plan revealed that Seattle drivers would be paying for the Green Line 50 to 75 years into the future.

With revenue 30 percent under projections and construction costs 20 percent over budget for a pared-down line, SMP has become the region's latest example of a transportation agency woefully underfunding its mission.

At the most basic level, local and county road budgets will become more strained every year under voter initiatives that eliminated the vehicle-license fee and imposed a 1-percent cap (below the rate of inflation) on revenue growth. Seattle alone faces a staggering, $500 million backlog of deferred road-, bridge- and sidewalk-repair projects.

We keep making down payments on a growing number of grand ideas with no thought of how to afford all the mortgages. With a limited menu of tax options and a limit to what taxpayers can afford, we need to be realistic — and honest — in what we offer to citizens.

By competing for limited tax dollars and then breaking faith with voters, each transportation agency's priority project risks jeopardizing everyone else's programs, and the enhanced mobility that goes with them.

In the case of transit in downtown Seattle, does it make sense to duplicate transit infrastructure with light rail on Third Avenue and monorail on Second Avenue? Wouldn't one integrated infrastructure investment be more cost-effective?

Citizens need and deserve a clear, coordinated strategy that allows us to succeed in attaining the modern, multimodal transportation system we've envisioned. That can only be achieved by effective communication among the elected leaders responsible for our transportation choices and our mobility future — if we are to have one. That is why I sent a letter to regional leaders in Pierce, King and Snohomish counties asking them to convene a transportation summit.

We must ask the tough questions about which mobility investments we can afford and which investments we can't afford to put off, how they will be coordinated and integrated, and most importantly, how we will ration-ally pay for each of them.