To some, the Casey Overpass is a relic that divides Jamaica Plain and keeps drivers in their cars, zipping over local businesses that desperately need their dollars.
To others, the bridge is a crucial time-saver, ferrying motorists on the Arborway over traffic-clogged Forest Hills in a city always in a rush.
The overpass may be either a vital link or an antiquated barrier, depending on your point of view, but now it is coming down.
“I grew up in Jamaica Plain, and I lived here all my life,’’ said 72-year-old resident John Lovett. “I can’t believe it’s happening.”
Pete Stidman, who heads the Boston Cyclists Union, and other supporters of taking down the bridge, see something more.
They “are hoping for a neighborhood that is based on people, not cars,’’ he said. “If you create something that invites people to bike and walk, you can build on that.”
After years of planning and community meetings, the state Department of Transportation will raze the hulking Monsignor William J. Casey Overpass, and construct a system of ground-level roadways slated for completion by 2017. The design will include more lanes, enhanced walkways and bike paths, and additional open space for a farmer’s market. The $74 million project — stretching from Washington and South streets to Shea Circle — also envisions a new entrance to the Orange Line’s Forest Hills Station.
The state had deemed the overpass, built over the old elevated train line, structurally unsound in 2010, saying massive deficiencies in the span were “beyond the point of effective repair” after years of deterioration compounded by flaws in the original design. The 1,650-foot-long overpass — a legacy of 1950s highway construction design — carries 24,000 drivers daily across the Arborway.
On Saturday, the westbound lane to Jamaica Pond was shuttered. The overpass closes for good next weekend. Demolition is set for May 18. Rush-hour travelers are urged to add extra time to their commute.
Supporters of dismantling the overpass — such as WalkBoston, the Boston Cyclists Union, and the Emerald Necklace Conservancy — said the reconfiguration will open up the Forest Hills section of Jamaica Plain to the rest of the community, and connect a broken link along the Emerald Necklace.
“You can re-create the feeling of the Arborway and connect the [Arnold] Arboretum to Franklin Park,’’ said Julie Crockford, president of the Emerald Necklace Conservancy. “When you have a flyover and whiz people through, you have a broken link, and for Jamaica Plain you have a bifurcated neighborhood.”
But opponents, including members of Bridging Forest Hills, have waged a battle to block the demolition, armed with a long list of complaints. A community meeting was held Thursday.
They blame the state for not properly informing residents in other sections of the city, such as Hyde Park and Mattapan, who will be affected by the change. They pushed officials to consider replacing the decaying bridge or reconstructing it. And they voiced concerns about what they said would be a deluge of traffic along side streets, jamming neighborhoods and making it unsafe for pedestrians.
“I want a bridge at Forest Hills. The question is, do I want this bridge or do I want another one?’’ said Jeffrey Ferris, owner of Ferris Wheels Bike Shop and a member of Bridging Forest Hills.
Robert Peters, who lives in Mattapan, said many people in his community are just learning about the demolition, and many are not happy.
“It’s like they are trying to hobble us as a community,’’ he said.
Crockford, who served on a working group that reviewed the project, said officials spent hundreds of hours poring over plans and traffic studies before giving the green light. She said traffic specialists determined the new roadway configuration would add an extra minute to commuting times.
Crockford said the bridge was built in an era when transportation officials fixated on keeping people in their cars and out of the community. But officials are now focused on getting people to walk more, use their bikes, and burn less energy.
As the demolition moves ahead, City Councilor Timothy McCarthy, who represents Mattapan, Hyde Park, and Roslindale, said it is time to look forward.
“It’s coming down. It’s a state project. They’ve made their decision. The community process has been vetted,’’ McCarthy said. “My job is to . . . hold their feet to the fire and to make sure that the transition from bridge to ground level is as smooth as possible.”
Councilor Matt O’Malley, whose district includes Jamaica Plain, said that moving forward, his efforts will focus on construction and traffic management, support for local businesses, and improvements to the public transit system.
“When all is said and done, I hope that we have a safe, clean, thriving subdistrict of a neighborhood,’’ O’Malley said. “I’m hopeful we can make sure that Forest Hills . . . is a thriving, wonderful part of the city.”
State transportation spokesman Michael Verseckes said officials are working to minimize delays during construction. A system of temporary traffic signals will be installed and programmed to accommodate heavy traffic. And police officers will help move traffic along.
Related:firstname.lastname@example.org. Follow her on Twitter @meghanirons.