Even before a single piece of steel has been laid on I-90 for light rail, Sound Transit is looking ahead to what is next.

The agency is asking drivers and riders, students and businesses, those abled or not, where should mass transit go when current projects are complete in 2023?

The agency has completed a Draft Supplemental Environmental Impact Statement for updating the regional transit Long-Range Plan and is asking for input.

We believe in planning ahead. But it is hard to imagine how meaningful any input can be now when the way people move about now — whether it is to school or work or the doctor — is rapidly changing.

But Sound Transit has.

The population of our region is expected to increase by nearly a third by 2040. No doubt planners at Sound Transit have modeled several scenarios regarding how this growth will shape the region. The region’s mobility and economy depend on moving more people on mass transit. It is crucial to get it right.

At the same time, the state’s Transportation Commission is putting together a 20-year plan for improvements needed statewide. They are also completing a study on switching from a gas tax approach to paying for transportation improvements to a road usage charge. Gas tax revenues have fallen and probably won’t bounce back. Cars are more efficient and people are driving less. Fewer people are expected to even own cars in the future.

Do these two plans matter? You bet they will. They will not only determine the “how” but the “where.”  Where investments in infrastructure go, so goes development and housing. These plans will determine how we will pay for and use these trains or buses or moving sidewalks. They will determine what life will be like in the Puget Sound region for decades to come.

For more on Sound Transit’s Draft SEIS, go to soundtransit.org/longrangeplan. For the state Transportation Commission, go to www.wstc.wa.gov/.