The Boston area is famous for its world-class medical facilities. But we don’t need a doctor to tell us that we have a clogged artery that’s affecting the health of the region.

It’s called I-93, and it’s congested with cars. Lots of them.

And it’s not just the blood pressure of drivers that’s at stake. The communities split by I-93 suffer from poor air quality and too much traffic on local streets. The businesses afflicted by delayed employees pay a price. Commuters and families lose valuable time, and no one benefits (except auto body shops, because we pay so much to fix fender benders and dented rims).

Of course, I-93 is not the only road with Avoidable Congestion Disorder. ACD afflicts roads, and drivers all over Eastern Massachusetts. And ACD takes a long-term toll: tomorrow’s businesses and workforce has no patience for congestion, particularly when jobs and businesses can relocate anywhere in our mobile economy.

But fortunately, there is a cure: extending the Green Line.

The Green Line Extension will move 45,000 passengers a day, on trains that will each carry the equivalent of 200 or more single passenger vehicles. That’s 26,000 highway miles traveled every day, including many driven by residents and workers in Somerville, Medford, Arlington and other communities who will be off the road. All avoided with GLX.

Like most smart public transit investments, GLX comes with many positive side effects: roughly $4 billion in private investment in our economy, 30,000 permanent jobs, 30,000 construction jobs and $3 billion in projected tax revenue by the year 2040.

And the environmental benefits of GLX are significant. Your community, your children and future generations will benefit by cleaner air. Reduced congestion on I-93 and nearby roads will remove exhaust from the air we all share, and reduced carbon emissions will slow climate change.

GLX was legally mandated back when the Big Dig was approved long ago. And work has been underway for several years. It’s not inexpensive – far from it.

State officials have raised legitimate cost concerns about the project, which for all of its advantages did not have proper oversight until recently. But a new team is working diligently to develop a responsible and manageable budget for the project.

Transit serves everyone, whether we ride or not. Every taxpayer in the Commonwealth should be rooting for the new team to succeed in saving the project, including all of the planned stations, including the Route 16 station, and the complete community path for walkers and cyclists, and not only to avoid wasting tax dollars already expended.

Stopping construction now would be costly since the state would be on the hook for about $700 million on sunk costs. Moreover, the state would lose $1 billion in federal funding obtained through the hard work of U.S. Rep. Michael Capuano, and other members of the state’s congressional delegation.

Hundreds of millions in savings have been identified by the new project team already. Slimmed down stations, reconfigured bridge designs, and operational efficiencies offer real hope to get the project back on track. If we don’t, we’ll have squandered the equivalent of $1.7 billion. And we will be stuck with ACD!

Massachusetts deserves better. Everybody benefits from good public transportation like GLX: Riders, employers, retailers, sports teams and fans, neighbors, and of course, drivers. And, the Community Path creates 55 continuous off road biking and pedestrian miles by connecting the Charles River paths with the Minuteman Trail.

ACD is bad for everyone. GLX – at the right price – is good for everyone. So along with many others, I’m counting on Gov. Baker’s team to keep GLX costs under control, and move forward with this transformative project.

The stakes are high. If our state can’t make this work, we will lose a once-in-a-generation opportunity to give commuters a break, and to become more competitive as a region in the coming decades. Now is not the time to pull the plug on GLX. Now is the time to buckle down, find smart cost-saving solutions to ACD, and show the nation and the world that Massachusetts – a leader in life sciences and much more - can fix what ails us.

Kristina Egan is the director of transportation for Massachusetts, a statewide coalition promoting a 21st century transportation system.