A contractor walks to cut down a tree and clear out space along the Georgetown Branch Trail last month to make way for the Purple Line. (Ricky Carioti/The Washington Post)

Motorists in the Maryland suburbs are about to feel the pain of lane closures and even more traffic tie-ups than normal as 13 miles of some of the area's most congested roads are ripped up to build the Purple Line.

Project officials are implementing a "maintenance of traffic" plan several years in the making that details when and where roads will be narrowed or closed during four to five years of light-rail construction. A synopsis of the plan provided to The Washington Post shows that tens of thousands of motorists will lose lanes on almost every major road along or across the rail alignment between Montgomery and Prince George's counties at some point.

Intermittent lane closures for tree-cutting have started and will become widespread by early next year, when workers will begin moving utility lines. The enormous construction site will span some of the most densely populated Washington suburbs inside the Capital Beltway.

"There's obviously a lot of challenges being that you're building where people live and work and are walking through a construction site," said Carla Julian, a spokeswoman for Purple Line Transit Partners, a team of companies building the line as part of a public-private partnership with the Maryland Transit Administration.

"It takes an immense amount of planning to keep pedestrians and cars moving safely," Julian said. "It's going to take some getting used to."

Construction will occur simultaneously along the entire 16-mile alignment between Bethesda in Montgomery County and New Carrollton in Prince George's County, Julian said.

Because the western three-mile segment will be built along the closed Georgetown Branch recreational trail, most of the traffic effects will be felt in and east of downtown Silver Spring.

Motorists will have to navigate construction zones both on the mostly east-west roads that will carry trains, as well as the north-south roads that will cross the line.

The major roads affected include Connecticut Avenue, 16th Street, Colesville Road, University Boulevard, Baltimore Avenue (Route 1), East-West Highway (Route 410)/Riverdale Road, and Veterans Parkway. Most will have periodic lane closures, either to build Purple Line bridges over them or to install tracks in new pavement.

One particularly tricky area will be Georgia Avenue near Bonifant Street in downtown Silver Spring, where lanes will be closed and traffic shifted to rebuild the intersection.

"That Georgia Avenue piece is going to be challenging," Julian said. "There are so many cars on that road, and it will be a big work zone there."

Three roads — Plymouth and Arliss streets in Silver Spring and parts of Ellin Road in New Carrollton — will be closed for much of the next several years. Bridges will be closed and rebuilt over the CSX railroad tracks on Lyttonsville Place in Lyttonsville and on Spring Street near 16th Street in Silver Spring.

In downtown Bethesda, part of Elm Street off Wisconsin Avenue closed recently to build an elevator connection between the street-level Purple Line and the underground Metro Red Line station.

Campus Drive on the University of Maryland campus could close during some summer months, according to the plan.

Residents and businesses will maintain access to driveways even when streets are closed, Julian said.

In Riverdale, John Arrington said he and other residents are bracing for longer backups on Riverdale Road (Route 410). He said single lanes that have been closed for an hour or two for early utility work and soil borings created traffic jams that left motorists waiting through two to three cycles of the light to clear intersections.

Arrington, president of the Eastpines Citizens Association, said he and many other residents are looking forward to one day riding the Purple Line. But now, he said, "People are scared of the construction and the disruptions."

Some business owners say they're worried that snarled traffic will mean fewer customers.

Abeba Tsegaye said she and her sister, Lene, have noticed business drop off even with minor street construction outside Kefa Cafe, their Silver Spring coffee shop. Losing street parking and having Purple Line construction outside their front door on Bonifant Street for 18 months has them worried it will "kill the business."

"I don't want to be negative because in the end [the Purple Line] might be a good thing," Abeba Tsegaye said. "But until then, it's going to be crazy and will really affect smaller businesses like us."

Although the $2.4 billion Purple Line is a state project, local officials say they'll keep an eye on the traffic effects.

Tim Cupples, who is overseeing Purple Line construction for Montgomery County, said the county's traffic management center will "tweak" traffic signal timing to try to keep traffic moving and will keep tabs on traffic cutting through neighborhoods.

"Like any major construction project, we realize there are going to be some inconveniences and some severe impacts on residents," said Esther Bowring, spokeswoman for the Montgomery transportation department. "But we hope the long-term benefits of this project are going to outweigh those concerns."

The major impacts in the traffic plan are scheduled to be posted on the project website, purplelinemd.com, in the next two weeks, Julian said. Motorists and residents also can sign up to receive construction notices on the website, under the "construction" tab.

This story has been updated.