Americans may be rethinking what they want their 21st-century transportation system to look like when it grows up, but in the D.C. region, we still want it all: Better highways and trains, faster buses, new streetcars and more bike lanes.

The year gone by was a big one for traffic and transit changes, and 2013 is likely to match it. Out of many candidates, these are the top 10 things we picked for our watch list.

Silver Line

If completion of the Dulles Metrorail project’s first construction phase goes smoothly, and if Metro’s testing of the system is equally trouble-free, transit riders may take their first trips on the Silver Line by the end of this year.

The new line will provide a transit alternative for many commuters and help focus development in Tysons, making this one of the transportation highlights of the still-young century. But it will bring disruptions that also must be studied by planners and politicians.

Accommodating the Silver Line will bump more trains from the Blue Line and reduce Orange Line service between Vienna and East Falls Church. Some bus routes that connect with the Orange Line stations will move to the Silver Line. Will commuters be willing to modify their behavior as service shifts?

11th Street Bridge

The construction of the 11th Street Bridge’s three spans over the Anacostia River and the ramps that connect them to various roadways will be completed. Many commuters will be learning how to best use the new freeway connections, while others will explore new neighborhood-to-neighborhood links across the bridge’s local span.

Meanwhile, this winter, the D.C. Department of Transportation will complete the shutdown of the Southeast Freeway segment just west of Barney Circle so that work can continue on raising the roadway and converting it into a boulevard, with links to the adjacent communities. That work will continue all year.

Wilson Bridge project

A project that involved not only rebuilding and widening the Woodrow Wilson Bridge over the Potomac River but also reconstructing four adjacent interchanges is substantially done, but project managers have until June to wrap up the remaining work.

Commuters already are experiencing most of the changes wrought by the project, but its formal completion will remind the D.C. region that it is possible for jurisdictions to cooperate on major transportation improvements. Perhaps it also will remind the area that the bridge was designed so two lanes could serve as transit ways, an option still available.

Intercounty Connector

Construction also will continue on the biggest new road project in the D.C. suburbs of Maryland. The Intercounty Connector extension from Interstate 95 to Route 1 and the extended merge lanes along I-95 got underway in 2012 and are scheduled to be done in 2014. The work has not been very disruptive for commuters, but watch the speed cameras in the I-95 part of the work zone.

The Maryland Transportation Authority, which operates the state’s toll roads, is scheduled to decide this winter whether to raise the 55 mph speed limit to 60 mph following a lengthy traffic safety study.

Marylanders will see plenty of other projects get underway, and some will have a big impact on commuters, including the reconstruction starting this spring of the bridge that takes University Boulevard over the Capital Beltway in Silver Spring.

Beltway buses

The 495 Express Lanes opened to drivers in November, but it’s really not till this year that we can begin to learn whether these specialized lanes can live up to their potential. We need to see not only whether drivers find it worthwhile to pay a variable toll for a reliable trip, but also whether commuters flock to new Fairfax Connector bus services designed to take advantage of the express route into Tysons.

Commuter buses have great potential to get solo drivers out of their cars, so long as those buses don’t get stuck in traffic along with everyone else.

A success in the 495 Express Lanes could inspire others to advance the cause of dedicated bus lanes.

D.C. streetcars

D.C. Department of Transportation officials hope they can begin operating the city’s first modern streetcar line by the end of 2013. For much of the year, people who live and work along the H Street/Benning Road corridor will see preparations for passenger operations, including the testing of the streetcars, three of which the District already has. The other three are under construction in Oregon.

Capital Bikeshare

The popular bike-sharing program will expand even more this year. In the District, 54 new Capital Bikeshare stations are scheduled to open by March, according to the District Department of Transportation.

In Arlington County, more than 30 new stations will be installed, with an emphasis on expanding to areas including Shirlington, Fairlington and along Columbia Pike. That will give the District 192 stations, while Arlington will have nearly 80. Montgomery County expects to join in with 50 stations this year. Meanwhile, the District plans to create a bike lane on M Street NW to complement the new one on L Street between 14th to 24th streets.

I-95 Express Lanes

Construction that began in mid-2012 will continue on the I-95 Express Lanes, one of the biggest road projects in the D.C. region. This project, scheduled for completion in 2014, will create high-occupancy toll lanes between the Edsall Road area of Interstate 395 and Garrison Road along I-95 in Stafford County. Same rules as the 495 Express Lanes: They will be free for three or more in a car, as long as it has an E-ZPass Flex, but others can opt to pay the toll for the assurance of a reliable trip.

That’s not the only construction along that corridor. The shoulders on I-95 will be upgraded between the Occoquan River and Quantico for use during accidents and other emergencies, the Virginia Department of Transportation said. This work is scheduled to begin in the spring and wrap up in 2015.

Route 50 interchange

This VDOT project in Arlington is a step below the mega monsters, like the I-95 Express Lanes, but it’s a high-impact job in its construction phase and in its consequences for commuters when complete. The bridges and ramps at the junction of Route 50 (Arlington Boulevard), Courthouse Road and 10th Street in the Clarendon area are being replaced to ease the difficult merges with Route 50. The project should wrap up at the end of the year.

I-66 widening

VDOT is scheduled to begin work later this year on an additional lane in each direction of Interstate 66 between Route 29 in Gainesville and Route 15 in Haymarket. The project, the latest in a series of I-66 widenings outside the Beltway, is scheduled to be done in 2015.