ACTON — In the Acton Plaza Shopping Center, where SUVs and minivans clog the parking lot, "Help Wanted" signs crop up everywhere, from the window of a hamburger spot to the chalkboard of a pet store to the produce section of the Roche Bros. supermarket.
Thirty miles away, in Boston's Mattapan Square, such signs are hard to find. Some storefronts are vacant, including the McDonald's that closed over the summer.
"That was a shock for us," said Patti Powell, a hairstylist who said she has lived in Mattapan all her life. "They were here one day and then, poof, gone just like that."
Massachusetts' booming economy is generating the strongest job growth since the late 1990s, but as these starkly different commercial areas show, jobs are not expanding fast enough where they're needed most. Economists said this mismatch between jobs and job seekers remains one of the most vexing challenges for policy makers hoping to spread the benefits of the recovery and prevent the division between rich and poor from hardening.
In Mattapan and Acton, the gulf is both longstanding and getting wider. In 2000, for example, the median income in Acton was almost $53,000 higher than in Mattapan; in 2013, the gap increased to $64,580, according to the most recent local data from the US Census Bureau.
Poverty in Acton during this period fell by half, to less than 1 percent of families from about 1.7 percent. The share of families living in poverty in Mattapan rose to 16 percent from 14.5 percent.
In Acton, a well-to-do bedroom community, the median household income is $110,000 — more than 60 percent above the state median of about $67,000. Store managers say they struggle to fill job openings.
In urban Mattapan Square, only 20 minutes from downtown Boston, jobs are more scarce. One in eight workers in the neighborhood are unemployed, according to the census data, and the $45,000-a-year median household income is one-third below the state median. While some business owners insist there jobs to be had in the square, few say they are actually hiring.
"The nature of the rebound is so uneven," said University of Massachusetts Amherst economics professor Robert N. Pollin. "There is employment, and it follows where the market is. And it's not in working-class communities. It's starkly concentrated at the top."
Bridging the gap between places like Mattapan and Acton has been the subject of research and analysis for decades, said Kevin Lang, a professor of labor economics at Boston University. The government has had limited success with efforts to boost business development and employment in struggling commercial districts by creating "empowerment zones" and offering subsidies.
And without a car, it's almost impossible for someone in Mattapan looking for work to get to a place like Acton, he said. There is no bus service in Acton, a town of 22,000, and the commuter rail is miles from commercial shopping and can cost more than $10 each way.
"That's hard to fix," said Lang. "You're in a vicious circle. No money to afford a car, and without a car you can't get a job."
The pathway to a job at a place like Roche Bros. at the Route 111 shopping plaza begins with a part-time job and can often result in a full-time job with benefits, said Jim Lundy, the supermarket's general manager. Right now, staffing is one of the store's biggest challenges.
"It's tough," Lundy said. "And we're very competitive with wages."
A daytime cashier can make $9.75 an hour, more than the state's $9 minimum wage. A meat counter worker can make $10 or more an hour, and drivers for its new delivery service earn $12 and up.
One of the most popular Mattapan spots for decades has been Brothers, a counter service restaurant that serves hearty portions of smoked pork chops, meat loaf and red velvet cake, and has a wall filled with autographed photos of celebrities, from the Supremes' Mary Wilson to 1980s rappers Run-DMC.
Chris Natale, whose family has run the chain for three generations, said it's easy to find a job in Mattapan Square. But, he added, he's not hiring.
Some longtime shop owners also said it's increasingly difficult to just stay in business, let alone add more employees. Bea Jung, who owns the clothing store J City with her husband, said rent is going up more than $1,500 a month, forcing them to close the business after 30 years.
They will lay off one full-time and one part -time worker when they shut down after the holidays. A giant sign hanging at the storefront says "Everything Must Go" and "God Bless You." Piled on tables inside the shop are Puma sneakers marked down to $10 from $30, Dickies jumpsuits for $29.99, and T-shirts for $3.99.
The couple had hoped to remain in business another decade before retiring, but working 12 hours a day became too much.
"It's not busy like it used to be," Jung said. "The economy's not so good and we work too hard and make no money."
In Acton, a 14,000-square-foot CVS recently opened across the street from the Acton Plaza Shopping Center, built from the ground up and offering an astounding selection of hair products, as well as an increasing amount of food. If anything, foot and car traffic has increased, which has been good for the nearby Not Your Average Joe's restaurant.
Adam Rutstein, the general manager, said sales are up and he's hiring for every restaurant position except host. Filling those jobs is difficult in a town where unemployment was 3.3 percent last month, lower than the state average of 4.6 percent.
"Our talent pool is not Acton, it's people who need hourly jobs," he said, "so we have to pull from 20 minutes away."
Most economists said it's difficult to justify driving any further than that for a lower-paying retail or service jobs.
So the divide, said Megan Way, an labor economics professor at Babson College, ultimately "keeps people segregated."
Rutstein, the restaurant manager, said he draws loads of job applicants from nearby towns like Maynard and Framingham, and yet not enough to fill all the open positions.
"The need for workers," he said, "it's epidemic."