What transit package? What election year?

The case for fast-tracking the expansion of mass transit expansion in the Puget Sound region should be self-evident by now.

With the price of gasoline now exceeding $4.30 a gallon, Sound Transit is seeing a swell of new riders – a 15 percent increase between April 2007 and April 2008. Many more would flock to trains and buses if the networks reached farther and were more convenient.

That lends urgency to the two big questions now before the Sound Transit board: whether to put a new train-and-bus package on the November ballot, and if so, what ought to be in that package.

The board is tackling the second question first; it may decide on a package Thursday. In April, it narrowed the choices down to three:

 • The ambitious mix of projects that was rejected by the voters last November, which included the extension of light rail from Sea-Tac airport to the Tacoma Dome over a 20-year period. This looks like a nonstarter. Even $6 gasoline might not do much for a plan that wouldn’t deliver some of the goods until 2027.

 • A fairly modest 12-year plan financed by a 0.4 percent sales tax increase. This would extend light rail – but not very far to the north and south. On this end, the trains would reach only to South 200th Street.

 • A larger 12-year expansion that would get light rail to Highline Community College at South 240th.

All these options would pay for more express buses running between the region’s cities, and more Sounder trips between Tacoma and Seattle through the Kent Valley.

If the board opts to put a package on the ballot, it ought to deliver as much service to Pierce and Snohomish counties as possible without taking 20 years to do it.

The 0.5 percent option, for example, beats the 0.4 percent option. Voters will be looking over the project list and asking themselves if they want any tax increase. More service would be a bigger selling point than a 0.1 percent price advantage.

But the threshold question is whether to punt any package to the 2009 or 2010 ballot, a decision to be made next month.

There are good arguments for waiting. The state’s economy is weak. Some of the proposed transit projects could use more vetting. The board doesn’t have any up-to-date polls indicating how the public might swing.

The wild card is the cost of gasoline. The surge in prices will eventually persuade citizens to invest more in alternatives to the automobile. Eventually. If voters are still reeling from sticker shock at the pumps in November, they may be in no mood to tax themselves for projects that won’t materialize in 10 or 12 years.

But if they realize that budget-busting gas prices are here to stay, an immediate start on transit improvements will look more compelling.

The board must somehow read the public right – and take a gamble. The stakes are high. A second, consecutive failure at the polls could kill the chances of transit expansion for far too long.