A new ridership forecast for a potential rail system on O'ahu paints a sobering picture of the island's traffic woes: While rail transit is expected to alleviate congestion by 10 percent by its completion date in 2030, congestion is expected to be far worse by then because of an estimated 30 percent population growth for O'ahu in that time.

Clearly, these numbers illustrate the need for several transit options going forward, including rail transit. That's why it's good to see alternatives, such as expanding our bus system and managing our highways, also under review.

According to the new forecast released last week by the city and transit consultant Parsons Brinckerhoff Quade & Douglas, the largest ridership would come from a fixed-rail system.

That's encouraging. To preserve our environment, the focus should be on how to best move people, not cars. Building superhighways with added capacity is not the answer.

Developing a transit culture takes time. O'ahu residents have been tied to their vehicles to get around for generations, and many have not experienced transit systems that are second nature for many Mainland residents. With time, ridership will grow.

O'ahu had the chance to be forward-looking in 1992, when we came amazingly close to acquiring a similar transit system that would have cost billions less, with 30 percent of the tab covered by federal dollars.

Unfortunately, the pressure of politics sent that plan down the river. Bad move.

Now, with an eye on the future, it's time to move forward.

No doubt, building a rail system will cost us, as will any expansion of buses or highway management plans.

The reality is the economic and social costs of doing nothing will be far greater.