Some state senators have put O'ahu's proposed fixed-guideway mass transit system on notice: Get moving or else.

A state Senate bill (SB 3213) would suspend the collection of tax dollars for the system if the transit technology is not chosen by June 30. And if certain contracts aren't awarded by Dec. 31, the money would revert to the state highway fund and be used for other O'ahu traffic needs — which could effectively kill the fixed-guideway project.

The bill's sponsors say they want to make sure the city doesn't waste any more time bickering over the transit plan as county tax surcharge revenues — about $148 million and counting — keep piling up unused while other necessary projects go begging.

The impatience is understandable: The City Council and the mayor's office have been haggling over fixed guideways since Frank Fasi's heyday in the 1970s.

But times are different now. East-west traffic jams are bordering on gridlock; both the council and mayor agree a long-term solution is necessary. The mayor is committed to the fixed guideway system, and the council approved the surcharge to move the project forward and help qualify for matching federal funds.

Given the scope of what's at stake — the biggest public works project in Hawai'i's history, affecting Honolulu for generations to come — the need for careful planning and execution should be obvious.

So for senators to suddenly issue arbitrary deadlines and dire threats to shut the entire thing down if contracts aren't signed by December is capricious at best. There are more sensible ways to conduct the taxpayers' business.

The council and mayor have certain duties to the residents of O'ahu to ensure the long-term viability of the project, whatever its final form. Public input during the process will continue to be important.

And even though the mayor's office is confident it can meet the senators' deadlines, there's no good reason the entire future of the system should depend on its doing so.

If legislators want a voice in the city's transit operations, they should begin with discussions, not threats.