It was a sign in an Atlanta bus station in the summer of 1961 that awoke something in a teenage Lucy Buckner.

"I was on a Greyhound bus and they had the 'colored only' signs on the water fountains," she recalled. "Having grown up in Ohio, I kind of wanted to test the water." A kindly Georgia aunt stopped her before she got into trouble. But something changed in Buckner that day. "That started it," she said.

Buckner, now a 68-year-old grandmother from Burnsville, will take part in her third civil rights march in Washington on Saturday to mark the 50th anniversary of her first: The 1963 March on Washington for Jobs and Freedom, the forum for Rev. Martin Luther King's transformative vision of racial justice.

On Friday morning, Buckner boarded the bus at Sabathani Community Center in south Minneapolis, joined by several dozen other marchers, all headed for the Lincoln Memorial, where King galvanized the early civil rights movement with his "I have a Dream" speech.

Much has changed in the last 50 years, Buckner said, while noting that much has stayed the same or even gone backward in the push for equal housing, education and employment. Her life has had its own ups and downs, including a divorce and the raising of three successful daughters. Her oldest, a Maryland police dispatcher, will meet her in Washington.

For Buckner, one constant is the need to keep the nation focused on King's dream. She marched the first time despite the fears of her father, who grew up in segregated Georgia and who lived just long enough to see Barack Obama become president. Buckner returned to Washington in 1983 for an anniversary march led by King's widow, Coretta Scott King.

Now, Buckner said, King's message is as relevant as ever. "Since I'm living," she said, "I'm going to march in 2013."

Hattie Bonds, the retired Minneapolis school principal who organized the bus ride from Minneapolis as part of the National Action Network, said Saturday's march is more than a commemoration of history.

"We're still struggling with jobs, justice, Dr. King's dream," Bonds said. "It's important for us to say, 'Look, we have not arrived just because we have an African-American president.' Let's stay focused and help our country to grow and get better."

Bonds points to a sweeping set of metrics in Minnesota that shows the scope of work yet to be done:

• The jobless rate for blacks in Minnesota is triple that of whites, creating one of the largest racial gaps in the nation, even compared to such Deep South as Memphis and Atlanta.

• Fewer than half of blacks in Minnesota graduate from high school, compared to four-fifths of whites.

• Rates of incarceration, free-lunch programs for students and foster care all are disproportionately high for black Minnesotans.

Nationally, the picture is much the same. A Pew Research Center poll released Thursday found that only 26 percent of African-Americans believe the situation for black people has improved in the past five years, while more than one in five say things are worse. That's in contrast to the 35 percent of whites who believe blacks have made progress in the past five years.

The march organizers recognize that different segments of society will argue about who is to blame or what should be done. This weekend's gathering in Washington, they said, is intended to serve as a visual reminder that inequality still exists in America.

Bonds sees it not only as an economic fact, but a political one as well.

"The big picture is the total disenfranchisement of certain people in our society," she said.

Postal workers join march

A large contingent of the Minneapolis bus riders are postal union workers, suggesting that many supporters see the march as part of a broader labor struggle that includes blacks and whites.

"Income inequality threatens our democracy as Jim Crow segregation did in 1963," said U.S. Rep. Keith Ellison, Minnesota's first black congressman, referring to the system of laws that oppressed blacks throughout the South at that time. "The minimum wage in 1963 was the equivalent of $9.54 in 2013 inflation-adjusted dollars. But today's minimum wage is only $7.25. Workers are falling behind."

In some ways, the bus riders paying $179.56 each for the three-day round trip feel like they're up against some of the same legal and political fights of the 1960s. Buckner pointed to a conservative movement toward stricter voter ID laws, which many liberals see as a form of voter suppression.

"It's déjà vu," Buckner said. "We're going through it again."

The list of modern racial grievances includes the Trayvon Martin case, in which George Zimmerman, a white Hispanic in Florida claiming self-defense, was acquitted in the shooting death of an unarmed black teenager.

"The 50th anniversary might be an opportunity, given what's happened in the last 50 years, for us all as Americans to sit and have the conversation the president asked us to have after the Trayvon murder," Twin Cities civil rights trailblazer Josie Johnson said in a video interview Wednesday with the University of Minnesota's Hubert H. Humphrey School of Public Affairs.

Johnson and some of the other torchbearers of the civil rights movement are not making the bus trip this year. A few, gray and on in years, chose to fly instead, according to Bonds. Johnson, a veteran of the '63 march, will mark the occasion next Wednesday as part of a Humphrey Institute forum.

Former Vice President Walter Mondale, who will be on the panel with Johnson, said in an interview Friday that "I don't think the country was ever the same again." Nevertheless, he said, "there's still a lot more to be done, and if King were here today he'd say the same thing."

Follow Kevin Diaz on Twitter @StribDiaz.