Danny Stevenson, right, waits for his bus on Columbia Pike in Arlington on June 8, 2013. After a proposed streetcar project fell through, some residents blamed demographic differences between northern and southern Arlington. (Joseph Victor Stefanchik/For The Washington Post)

Route 50 has longed marked a frontier of sorts in Arlington County. The highway imperfectly bisects the 26-square-mile suburb into a leafier, wealthier North Arlington and a less affluent, more diverse South Arlington. Everybody says so.

“My friends make jokes: ‘Are you sure you’re okay crossing Route 50 to come see us Southies?” said Brooke Fern, a regulation consultant who lives in Lyon Park, near Fort Myer. (Real estate agents have told her she lives in “southern North Arlington.”) “Some people pay a lot of attention to zip codes.”

In a liberal county that prides itself on consensus government and progressive values, the line has been seen as more of a description than a divide. But last week, activists and commenters on e-mail groups and social media blamed a north-south split for the collapse of a long-planned streetcar system along Columbia Pike, a costly project that supporters touted as a development boost for the county’s southern neighborhoods. The streetcar demise, they said, was the result of voters in North Arlington who weren’t willing to pump $550 million into a project that wouldn’t benefit them.

Unsettling questions were raised after the project’s cancellation: Are there two Arlingtons? And as the county of 215,000 people grows wealthier and whiter, will poorer, minority neighborhoods survive and be full beneficiaries in the vaunted “Arlington Way,” which puts a premium on citizen participation?

Two reporters tested perceptions about Arlington in grocery stores in both parts of the county, a Harris Teeter on Lee Highway and the Food Star on Columbia Pike. Both were crowded on a weekday afternoon, both carried plantains (at 79 cents a pound, they were a dime cheaper at Harris Teeter). And both were filled with Arlingtonians who were quick to recognize differences in the two sides of the county but equally loath to divide themselves into rival factions.

Children play in the interactive water feature at Penrose Square in Arlington on June 8, 2013. (Joseph Victor Stefanchik/For The Washington Post)

“It’s more expensive up there, but it’s very expensive around here, too,” said Santos Maurice, 52, a disabled construction worker who was waiting for shoppers by a church van in the Food Star parking lot. “Arlington is Arlington; it’s the same county.”

Elizabeth Tuomey, 37, has lived on both sides of Route 50. “I don’t really like the term ‘divide,’ but I think there are differences,” she said while selecting a box of strawberries at the Harris Teeter. “You can see it in the economy, in real estate, in the schools.”

Tuomey, a criminal defense lawyer in Arlington, bought a townhouse in Shirlington 10 years ago because that was all she could afford in a county where the median home price today is $530,000 and more than 1 in 5 single-family homes sell for $1 million and up. She liked the vibrant south, which she describes as being packed with apartments and single people. But when she and her husband were ready to start a family, they moved to Cherrydale, which she said is more about “kids and yards and dogs.”

They return often to restaurants near their old neighborhood, and Tuomey said she considers herself a resident of the “whole county.” When it comes to distributing government services to all residents north and south, she thinks the county is “absolutely fair.”

Louisa Marino, 56, lives near Shirlington and thinks that South Arlington does get its share of government services. While buying Morochas cookies at Food Star, she listed the excellent teachers her three children had, especially since they had to educate students speaking “Spanish, Arabic, Amharic — every language is in the schools.”

Her one complaint has been the pace of school renovation. Two of the county’s high schools are north of Arlington Boulevard and both were renovated before Wakefield, the school serving the southern part of the county. Residents countywide marveled at the $98 million LEED-certified redo of Yorktown High School (many a car in the Harris Teeter parking lot sported an oblong YHS sticker). Wakefield is nearly finished with its own
$113 million makeover.

“It took a long time to get our school,” said Marino. “But now it’s nearly done, and it is very nice, too.”

She paused. “Maybe not as nice as Yorktown, I don’t know. There are very nice neighborhoods around there.”

Some Arlingtonians rejected the idea of a neat north-south split. Jean Marie Mahaney had walked to the Harris Teeter and noted that there are modest homes along the way. Many, though, are dwarfed on at least one side by the bigger houses built by developers in recent years.

“It’s not really a north-south thing,” Mahaney said. “We have poor housing all over the county.”

But statistics make clear that income and property values are significantly higher in Arlington’s northern tier. It is one of the wealthiest enclaves in the nation, where about one-third of residents make more than $150,000 a year. But only 14 percent of households in the Columbia Pike area hit that mark. More than half make less than $75,000.

Those neighborhoods also are the most diverse. Some 65 percent of residents along the Pike are not white, compared with­
36 percent of residents countywide, census data shows.

“This is where the immigrants are,” Marino said. “That’s why I like it so much. I like diversity.”

North Arlington residents also express plenty of love for a community of mixed accents, traditions and cuisines. “We are not McLean,” one said.

Arlington County is one of the few places in the Washington region where the percentage of non-white residents is falling, according to an analysis of 2010 census data. One reason is the soaring cost of housing. With the average rent of a one-bedroom apartment in the county at $1,900 a month, poorer residents are finding little relief even in the cheaper precincts of South Arlington.

“A lot of my clients have moved to North Carolina and Georgia and Florida,” said Mai Kamcam, 31, a nail technician who was stacking jars of baby food in her basket at Food Star. She plans to decamp after the first of the year, taking her three kids to Atlanta in search of cheaper rents she’s heard about.

“There is a lot of building here,” she said, “but I don’t think poor people can afford to live anywhere in Arlington.”

John Hughes, a retired federal probation officer, has watched the cost of being an Arlingtonian skyrocket since he moved to the county 30 years ago. His son, an Arlington firefighter, is priced out of housing in the northern part of the county.

“I couldn’t even afford my own house today,” said Hughes, 63. He bought the home on Dittmar Road for $400,000 in 1999. Its value is nearing the million-
dollar mark.

Hughes doesn’t detect any animosity between North and South Arlington and he thinks the county does a good job “taking care of the whole gamut.” But he notes the stark changes every Thursday, when he drives to his weekly volunteer stint at the Arlington Food Assistance Center off of Four Mile Run Drive.

“I leave my nice street in North Arlington and head down George Mason, and it changes as soon as you go across Route 50,” Hughes said. “There are just a lot of working families down there that need a lot of help. That’s my county, too.”