By the time heavy construction begins on the $2.3 billion widening of Interstate 66 outside the Capital Beltway next year, commuters in western Prince William County will be able to sign up and pay for van-pool services through a smartphone app. Others will be able to tap their phones to summon a ride to a commuter bus lot.

Two recently approved projects embrace the use of Uber-like apps to expand commuting options in this sprawling area of Northern Virginia where car dependency is high, transit is limited and the once-popular van-pooling services are in decline.

“This is not just new technology for the area, it is also new technology and service in an area that has been a bit of a desert for transit options,” said Chuck Steigerwald, director of strategic planning at the Potomac and Rappahannock Transportation Commission (PRTC), which oversees a regional van-pool service and runs commuter buses from Prince William to Washington.

The apps will be critical, he said, to encouraging people to use transit and van-pool services during peak construction on the I-66 expansion, a project that also aims to change the way people move along the corridor.

“They are designed to create that commuting culture before those lanes open up,” Steigerwald said. “So in five years, you will have a different mobility pattern in this corridor.”

The initiatives are part of a package of 15 projects funded through the Northern Virginia Transportation Commission’s I-66 Commuter Choice program, which will use toll revenue from the new 66 Express Lanes. The latest set of projects, worth $12 million, were approved last month by the Commonwealth Transportation Board and focus on expanding bus service and improving access to park-and-ride facilities, bus stops, and Metrorail and Virginia Railway Express stations.

The investments are critical for the transformation of the I-66 corridor, regional transportation officials say. The expansion of I-66 outside the Beltway spans 22.5 miles from the Capital Beltway in Fairfax County to University Boulevard in Gainesville in Prince William. It will add high-occupancy toll (HOT) lanes to the corridor and expand travel lanes to include three general-purpose lanes in each direction; new and expanded transit service, including additional park-and-ride lots; and median space reserved for future rail service.

State transportation officials say the expansion will help reduce congestion along I-66, which experiences eight to 10 hours of gridlock daily, including weekends, and carries roughly 200,000 vehicles on an average day. But, officials say, the plan is to move more people in the corridor by getting as many as possible to shift their commutes from driving solo to riding the bus or joining a carpool.

The PRTC is planning to launch a free, on-demand ­microtransit service from the Gainesville and Haymarket neighborhoods to OmniRide commuter lots starting next summer. PRTC officials say the agency will develop an app to connect riders to rides. The $1.1. million project will provide transportation from residential areas to bus stops for commuters who don’t take the bus because of the challenges of using park-and-ride lots, which are already at capacity, officials said.

The funding will cover the cost of a software interface that will allow vehicle operators to respond to commuter requests with dynamic, real-time routing. It also will pay for vehicles, onboard vehicle hardware, transit operations and advertising of the services.

In another high-tech effort, the PRTC is creating a platform for a flexible van-pool program that will connect riders with van pools and facilitate payment of fares. The $317,600 project will enable the use of the technology to potentially transform the way van pools operate in Northern Virginia, said Robert Schneider, executive director of the PRTC.

Although van pools are a long-standing commuting option in Northern Virginia, customers have dwindled in the past decade as the region’s commuting patterns have changed. More people are telecommuting, and more are using VRE trains and commuter buses. The services themselves are partly to blame for the decline, officials said, because they lack the flexibility that today’s commuters demand.

The rule, Schneider said, is that once you sign up for a van pool, “you have to ride with that same van pool every single day. If I need the van pool only a few days, I have no option.” The PRTC wants to change that by creating an online platform that allows van-pool providers to fill open seats with commuters who need a ride only occasionally.

“What we want to introduce is another option that will allow people to arrange for a single ride on a van pool that has an empty seat,” Schneider said. There are as many as 560 van-poolers registered with the Vanpool Alliance. The Northern Virginia program works with 55 vendors, who operate as few as two or three van pools and as many as 50.

“The technology piece comes in by allowing ad hoc booking and also arranging for payment, because right now, there is no payment structure for this,” Schneider said. “Van-poolers don’t charge for a single ride. We want to introduce a program that allows that to happen. We think that will help van-poolers over time, maintain economic feasibility and will expand the attractiveness of van-pooling.”

PRTC officials say they hope the new programs will be just two more options for commuters as construction ramps up on the I-66 project. Already, bus service from Prince William to Washington has increased since the 66 Express Lanes opened in December. The 10 miles of HOT lanes inside the Beltway are a separate project that is part of the Transform 66 vision.

The PRTC added commuter bus trips in recent months, and in May, it offered half off Omni­Ride express bus fares as an incentive. The discounted fares will remain in effect during construction, which is expected to last four years, and apply to buses running from Manassas and Gainesville to Washington, the Pentagon and the Tysons Metro station.

Construction is underway on more park-and-ride facilities, ­officials said, adding that they anticipate the transition also could boost the corridor’s culture of “slugging,” or organized hitchhiking .

“Part of the appeal of these programs is that they are nimble, flexible and targeted specifically toward the demographics and needs of Prince William County,” said Kate Mattice, executive director of the Northern Virginia Transportation Commission, which selects the projects to be funded with the I-66 toll revenue. “They should also provide a strong return on investment.”

Mattice said the initiatives are consistent with the goal of the I-66 Commuter Choice program to move more people through the corridor more efficiently.

“Constraints — such as a lack of available parking or a work schedule that doesn’t allow for joining a daily van pool — that prevent people from accessing transit make it more difficult for us to achieve that goal,” she said. “PRTC’s on-demand commuter lot shuttles and flexible van-pool program are great examples of using technology to tackle constraints and get more constituents out of their cars and onto transit.”