The effects of the month-long Orange Line shutdown from Oak Grove in Malden to Forest Hills in Jamaica Plain, set to start Friday (Aug. 19) at 9 p.m., will ripple throughout the Greater Boston region, bringing headaches for MBTA customers and drivers alike and increased congestion to an area already known for horrendous traffic.

MBTA riders who are considering driving a car instead of clambering into a free shuttle bus should stay off the road, according to Jonathan Gulliver, Gov. Baker’s highway chief. “If possible, avoid the region altogether until the diversion period has ended,” he said.

Companies should consider allowing employees to work from home, if they’re not already, Baker administration officials added.

The shutdown, which overlaps with a Green Line partial closure as well as the start of the new school year, is meant to cram five years’ worth of repairs and upgrades into 30 days. The fixes come as federal transit officials are scrutinizing a system that has seen a Red Line death, an Orange Line fire, and collisions on the Green Line.

By the end of the shutdown, new Orange Line cars, assembled in Western Massachusetts, will make up most of the fleet, which handles 100,000 trips every weekday.

The scramble to mitigate the effect of the closure has brought together the T and Boston City Hall. Mayor Wu said she’s working closely with T officials to ensure that things go “as smoothly as possible.” City transportation officials have added temporary bus lanes to speed the shuttles along their routes.

Wu and city school leaders sent a letter to parents last Friday outlining options for children taking the T. An estimated 23,000 students use the T to get to and from school, according to Boston Public Schools (BPS). Roughly 5,000 take the Orange Line.

“Students should plan for delays and ensure they leave additional time to get to and from school,” the letter advised. “There will not be any consequences for students’ late arrivals, within reason. BPS will plan to provide additional staff support to help guide students who are going to school along their route.”

The letter also notes the free shuttles – There will be a northern loop between Oak Grove and Government Center Stations and a southern loop between Back Bay/Copley and Forest Hills – and encourages jumping on the commuter rail, which is likely to be the “fastest way to travel.”

Riders can show their CharlieCard or CharlieTicket to ride at no charge between Zones 1A, 1, and 2. The Providence Line will make additional stops at Forest Hills before heading to Ruggles, Back Bay, and South Station, according to the letter.

On Tuesday, the MBTA said that it had provided city officials with 3,000 CharlieCards to distribute at the Boston Public Library and City Hall. In a separate but related move, City Hall is also offering a free 30-day pass for rentals of Bluebikes.

“The loss of a major transit line is a transportation emergency,” Jascha Franklin-Hodge, Wu’s chief of streets, told reporters at a Monday press conference with Baker officials. “But we are hopeful that we will look back on this moment as a turning point. Boston needs and deserves safe, reliable, fast transit, and while we expect the shutdown to be painful, it will provide an unprecedented opportunity to perform a large volume of critical work quickly. We are optimistic it will deliver the kind of real and tangible benefits to riders that we so clearly need.”

Asked by the Reporter if the Red Line will be the next to face a shutdown, Baker said, “I mean this really does end up being a case by case thing.”

With the Orange Line, there is the opportunity to do a “dramatic amount of work in a really short period of time,” he added. “It’s a big pain in the neck for everybody during the disruption. But there’s something coming out the other side that will be dramatically different and better, we believe.

“The Red Line cars are farther back in the process with respect to when they’re going to start to arrive,” he added, referring to the new Red Line cars that are getting assembled by a Chinese-owned company in Springfield, Mass.

“We’ve done a lot of Red Line weekend work for the past few years,” Baker said. “I don’t want to speak for [MBTA General Manager Steve Poftak], but I can tell you there’s nothing immediately planned other than keep doing the kind of work we’ve been doing on the Red Line.”

The Orange Line shutdown is also occurring in an election year, though Baker is not on the ballot since he opted against running for reelection. Attorney General Maura Healey, who does not face opposition in the Sept. 6 Democratic primary for governor, is set to face off in November against whoever wins the Republican primary: Either former state Rep. Geoff Diehl or businessman Chris Doughty.

On Tuesday, Healey rolled out her plan for the state’s transportation system, with the appointment of a “transportation safety chief” at the top of the to-do list.

“My plan will urgently address the failings at the MBTA, expand rail and buses across our state, and continue to fix our roads and bridges,” Healey said in a statement. “This will drive economic growth, create good-paying jobs, and support residents and businesses.”

Material from State House News Service was used in this report.