Commuters on I-66 will spend part of 2017 learning how to navigate new HOT lanes inside the Capital Beltway. (Matt McClain/The Washington Post)

In 2017, new interchanges will open, roadways will be widened, the express-lane tolling system will expand, and highway planners will work on moving more people with innovation rather than new asphalt.

Those plans affect tens of thousands of commuters. But the key to judging the health of the Washington region’s travel system will remain the performance of Metro. This has become more than just a practical matter about how best to move large numbers of people to work.

The troubles of the transit system have created a serialized drama that has many people looking forward to the next installment — if only out of morbid curiosity.

Just as “SafeTrack” became a subtitle to 2016, the year ahead will feature a Metro program called “Back2Good.” The name of this customer-service concept came from the riders Metro talked to. As the riders looked ahead to 2017, they had learned to curb their enthusiasm. “Back2Great” wouldn’t fly with them. Maybe that’s for 2018.

Meanwhile, here are five transportation stories to watch in the new year.

Metro. SafeTrack is scheduled to end this spring after completing repairs to 15 sections of track. Transit agency managers don’t want to have to replace it with SafeTrack 2.0, so they’re developing a preventive maintenance plan. The trade-off is that riders will lose eight off-peak and late-night hours of service for several years, starting this summer.

But that cutback is intended to make the rail system safer and more reliable. Potential cutbacks that soon will become part of a public hearing process are meant to save money in Metro’s next budget, which takes effect July 1.

These budget proposals have lurked in the shadows while Metro and regional leaders debated the preventive maintenance plan, but they are about to become hot topics.

For most riders, the gaps between rush-hour trains will probably grow. Only Blue Line riders might benefit from this change, because the gaps between their trains would decrease from 12 minutes to eight minutes. But the Yellow Line’s Rush Plus service, which diverts some riders from the Blue Line, would be eliminated.

Riders who may accept the cutback in hours for preventive maintenance will have a tougher time with the cutbacks in service to save money. That’s partly because rides still would cost more. Metro has proposed a 10-cent increase in the base fare at rush hours and a 25-cent increase in the base fare at off-peak hours.

General Manager Paul J. Wiedefeld’s budget, which still must be approved by the Metro board, is what he calls a “reality check,” and in 2017, that reality will probably be quite unpleasant.

Restoring the system’s lost riders will probably take years. Back2Good starts to sound mighty ambitious. The collection of programs gathered under that title are meant to improve parts of Metro’s infrastructure not addressed under SafeTrack.

Wiedefeld’s stated goal for 2017: “Service delays caused by track problems will be cut in half, and railcar-related delays will be cut by 25 percent.”

HOT lanes. For drivers, the biggest innovation of 2017 will be the conversion of the Interstate 66 lanes inside the Capital Beltway to high-occupancy toll lanes in the peak direction during rush hour. Those lanes have long been open only to high-occupancy vehicles during rush hours.

In contrast to the political debates that preceded this plan, the setup is easy. The tolling gantries and other infrastructure should be in place by summer.

But this still is going to take some getting used to. All drivers will need to have E-ZPasses to use the HOT lanes. If you’re driving solo, you’ll need the regular E-ZPass transponder. If you’re a carpool of at least two people, you’ll need an E-ZPass Flex switched to “HOV” to claim the free ride.

There’s more: Drivers on their way to and from Dulles International Airport who were exempt from the HOV rules won’t be exempt from the HOT lanes rules. And solo drivers who bought their way into the HOV lanes by purchasing hybrids will lose their exemption.

The saddest news is for the cheaters who simply drove solo in the carpool lanes knowing that it’s difficult for police to enforce the HOV rules. They’ll either have to pay the toll via E-ZPass, or go to the trouble of picking up a passenger.

The $100 million idea. Early in 2017, the Maryland Department of Transportation plans to announce the results of its search for innovative strategies to cut congestion on I-270, one of the D.C. region’s biggest and most crowded commuter routes.

“The winning proposer will move the most vehicles, fastest, farthest for $100 million,” Maryland Transportation Secretary Pete K. Rahn said during an online chat with me.

It’s an unusual approach. Most highway departments start with a plan and then try to find the money, rather than the other way around.

Rahn knows it would take a lot more money to meet a commuter’s definition of congestion relief. “I have no expectation that this $100 million project on I-270 will restore traffic to free-flow speeds,” he said. “My greatest hope is that we can at least keep people moving instead of being parked on I-270.”

South Capitol Street. The District Department of Transportation plans to begin its largest construction project, which over a few years will replace the Frederick Douglass Bridge, opened in 1950 over the Anacostia River, and recreate the nearby sections of South Capitol Street as a scenic boulevard.

The new, wider bridge will be parallel to the old one, near Nationals Park. A distinguishing feature of the project will be the construction of traffic ovals at each end of the bridge. This phase of the project, which District officials hope will be done in early 2021, also will include reconstruction of the interchange with the Suitland Parkway and I-295.

Inauguration. The Jan. 20 swearing-in of the new president will be a stress test for the capital region’s transportation system. Every four years, we get to see if the local road and rail network can move a crowd approximating the D.C. population into the blocks bounded by the Mall and Pennsylvania Avenue NW.

It tends to go remarkably well. That’s not to say it goes smoothly. The Mid-Atlantic weather can feature snow, rain, cold or warmth, creating conditions beyond the control of planners. It’s not a national holiday. The difficulties of getting visitors in and out are compounded by the need to provide regular transport for commuters.

How can this possibly work? Everyone in the transportation business knows it’s coming, and many have done this before. There are playbooks for various scenarios.

Other disruptive events will be part of life in the nation’s capital. The Women’s March on Washington is scheduled for the day after the inauguration. The annual March for Life is set for Jan. 27.

The Rock ‘n’ Roll Marathon, the sporting event that causes the most disruption on the District’s streets, is March 11. The National Cherry Blossom Festival is March 20 to April 16.