In my 27 years of involvement with public transportation, I have never seen it more popular. Ridership is at the highest levels in a half-century. Popularity is probably at an all-time high, as just about every major problem we face, from global warming to boosting the economy to lowering America’s dependence on oil imports, has public transportation as part of the solution.

Even T. Boone Pickens, the oil and gas billionaire, has called for greater conservation in his “Pickens Plan” to reduce our dependence on foreign oil, which partly involves driving less and using more public transportation. In short, what the industry has been saying for decades has now begun to resonate with the public. So why don’t we in the industry act like we believe it?

Revenue ideas do not match investment goals
It’s not that industry groups are being timid in their requests for more investment. APTA, for example, has called for more than doubling federal spending on buses, trains and other service over the next six years — more than $123 billion.

When it comes to asking for the revenues needed to achieve that level, however, we have been less bold. In fact, most industry groups have punted this issue, either choosing to defer discussion about how to get the money until the authorization debate is in full swing or ignoring it altogether.

That is not how the federal program grew successfully in the past decade and a half. In fact, public transportation investments grew significantly only when a dedicated revenue source was attached to them, such as a sales tax increase at the local level or a gasoline tax at the federal level. My guess is that it will be no different in the future.

Not only is the $123 billion figure impossible without new revenues, the current level of spending may be in jeopardy unless new money is found. That is because thanks to the high price of gasoline and the record switching to transit, the Highway Trust Fund is starting to show a deficit.

We must decide—soon
There are many ideas out there. Whether we choose to stick with the gas tax and index increases to match the need we have identified, or convert it to a percentage sales tax rather than a per-gallon one to capture some of the price increase as other nations do, or do we come up with something completely new such as a “carbon tax” or a dedicated piece of the fees in carbon permit trading exchanges as some have advocated? We must come up with something, and soon.

Failure to answer this key question will squander this historic opportunity to give public transportation the chance it deserves to be part of the solution for so many urgent problems we face in the world. That would be a tragedy.

Unless we don’t believe our own arguments.