We know that Earth Day is still two days away, but today we focus on greening our transportation system in the D.C. Metro area.

Over the next several decades, the D.C. metro area is expected to grow by 2 million new residents and add 1.6 million new jobs. How we decide to develop our transportation network to accommodate this growth will have a major impact on the region, shaping the urban landscape and quality of life. But transportation can also lead to some of the biggest environmental problems in and around the District. Air and water pollution, suburban sprawl, and global warming are all directly linked to transportation. For this week’s Transit on Thursday, DCist spoke with some of the area’s best and greenest to figure out how the District can move forward with efficient, cost-effective, and green solutions.