Maryland should take a lesson from Virginia's mistakes and scuttle its plans for an unaffordable 16-mile light-rail line connecting New Carrollton and Bethesda before it's too late. Like the Silver Line, the cost of the Purple Line continues to escalate. After two increases in two years, it's now up to $2.15 billion, and the state hasn't set aside a penny to build it.

The Federal Transit Administration provided $900 million to fund Phase 1 of the $5.6 billion Silver Line, but refused to fund Phase 2, leaving the Metropolitan Washington Airports Authority with a problem it still has not solved. The group Reston 20/20 predicts that jacking up tolls on the Dulles Toll Road to astronomical levels to pay for Phase 2 will force toll-avoiding drivers onto local Fairfax County roads and worsen Northern Virginia's already bad traffic congestion.

The Maryland Transportation Administration will also be limited to $900 million in New Starts funding for the Purple Line, which will cover less than half its $2.15 billion-plus price tag. Maryland's transportation trust fund has no money for new projects, according to the state's top budget analyst, and in just five years it will have to spend 80 percent of its transit funds and 100 percent of its highway funds just to maintain existing infrastructure.

As Tuesday's Examiner Local Editorial noted, the Metropolitan Washington Council of Governments' own analysis predicts that the percentage of all regional trips taken by mass transit will be just 7 percent in 2040, the same percentage it is now. It makes little sense to spend billions of dollars on mass transit that will be used by less than 10 percent of the regional population, while neglecting overburdened highways that 82 percent will use over the next three decades.

Unfortunately, this is exactly what both Virginia and Maryland intend to do.

Although Maryland's current Purple Line proposal is financially untenable, the original concept -- connecting the spokes on the Metro wheel to make using the existing Metrorail system more convenient for more people -- is still sound. Maryland should abandon this light-rail project it clearly cannot afford and switch to bus rapid transit, as recommended by the World Resources Institute back in 2009. It can perform the same function at a fraction of the cost.