Just a few years ago, Gabe Klein had no interest or intention of serving in government. But that’s not exactly how things turned out. In a span of just five years, he's led not one but two big city transportation departments.

That's unusual enough – city DOT directors typically don't jump from one city to the next -- but even more unique is the fact that he got to those positions despite lacking any background in government, engineering or urban planning.

But Klein – who announced his resignation Friday as head of the Chicago Department of Transportation – says he considers his time in government a success, not in spite of that nontraditional background but because of it. "I came at it from a completely different viewpoint," says Klein, who will serve through the end of the month. "I care about the cities I work in, and I care about people, and I care about the quality of life and moving people efficiently. I'm not really biased toward particular modes of transportation over others, except that some are much less efficient in certain cases."

That inefficient mode Klein is referring to is cars, which he believes have come to dominate the urban landscape much more than is appropriate. Indeed, Klein's overarching philosophy is that driving makes sense for trips of around 8 miles or more, but too often, people in urban areas use cars for trips that are less than a mile. "It just doesn't make sense," Klein says. "It's bad for the environment. It’s bad for cities. It’s bad for real estate."

That mindset turned him into something of a rarity: a DOT director who's known for focusing more on pedestrians, transit riders, and bicyclists than motorists.

Tapped by Chicago Mayor Rahm Emanuel in the spring of 2011, Klein previously led the Washington, D.C. transportation department from December 2008 to December 2010. During his short time in Chicago, Klein oversaw the launch of Divvy, a 300-station bike share program that dovetailed on the success he had with Capital Bikeshare in Washington, one of the biggest and most successful bike share programs in the country.

Under Klein, Chicago also got its first protected bike lanes, began construction of the Bloomingdale Trail, started work developing bus rapid transit, and launched speed cameras for traffic enforcement in school zones.

His departure comes at the same time as Janette Sadik-Khan, New York City Mayor Michael Bloomberg’s transportation commissioner, who will likely exit when a new mayor takes office in January. She is also a transportation commissioner who lacked the traditional focus on automobiles.

Though she has a different background from Klein, with more experience in government, she has also focused on bicycles and pedestrians. She generated national attention for installing hundreds of miles of bike lanes and blocking off parts of city streets -- including Broadway -- to turn into pedestrian plazas. The move infuriated some drivers but endeared her to others.

Klein and Sadik-Khan have achieved iconic status among advocates for bicycling and transit, and their near-simultaneous departures are causing many to take stock of their legacy. Aaron Naparstek, a visiting scholar at MIT’s urban studies department, says they’re both “transformative figures in the history of American cities." He said he considers their influence to be on par with that of Jane Jacobs and Robert Moses.

While many of the concepts both Klein and Sadik-Khan touted have been long-established in the urban planning community, it's particularly significant that the two work not there but in transportation departments. That’s because it’s DOTs that actually has the power to complete projects rather than just envision them. “The plan for a car-free Broadway through Times Square sat on a dusty shelf for 40 years until Janette came around and implemented it,” Naparstek says. “The real power to make these changes lies with these city agencies that actually have the guys with shovels working for them.”

Andy Clarke, president of the League of American Bicyclists, says their influence has extended beyond Chicago and New York. “I think what they’ve done in their own cities is impressive, but they’ve given so many other cities permission to do exciting stuff as well,” Clarke says.

Indeed, part of their legacy could be opening the door to different types of people running transportation departments, which in many places are dominated by engineers who focus on roads and cars. “I think the value of people who don’t see transportation … as an end in itself is really critical,” Clarke says.

Indeed, before taking over D.C.’s transportation department in December 2008, Klein worked as director of stores at Bikes USA, a major bike retailer; a co-founder of On The Fly, "an innovative, boutique food-serve company" that launched in 2007; and as an executive with Zipcar.

Klein says from his private-sector experience, he grew frustrated with government. Two of those businesses – early versions of car sharing and food trucks that are now ubiquitous in cities –weren’t easy to explain at the time. Was Zipcar a rental car or something else? Was the On The Fly a vehicle or a restaurant? The D.C. government’s slow answers to those questions were obstacles to expanding the businesses. “I considered the government to be a big roadblock.”

“What so many people in government do is they have a fear of being blamed for anything,” says Sam Schwartz, an engineering consultant who worked with Chicago on the Divvy project. “They try to get as many people on board and take the tiniest of steps. Gabe’s ready to just go out and do it after he gets some solid engineering and design input.

After then-D.C. Mayor Adrian Fenty tapped him to be transportation director, Klein quickly helped launch Capital Bikeshare, expanded the city’s Circulator bus system, and laid the groundwork for a streetcar. Fenty lost re-election, and when Emanuel won in Chicago, Klein helped his team with transition plans, including the mayor’s transportation policy.

He was already known to Emanuel through the city’s work installing bike share stations at the White House and closing off nearby streets for a farmer’s market. Meanwhile, Klein already knew Emanuel's brother Ezekiel, and in transportation circles he worked closely with another Illinois political player – then-U.S.Secretary of Transportation Ray LaHood – who was close to Emanuel. Suddenly Klein was leading his second big city DOT.

“I think people have seen you don’t have to be a traditional engineer that has worked for a consulting firm or worked their way up through the government to take over (a transportation department),” Klein says. “You also shouldn’t count them out. The important thing is not to put people in a box."

Klein and Sadik-Khan have helped put some glitz and glamour to a position that traditional hasn’t been known for it, generating lots of media headlines and adulation of hip urban thinkers. “They’ve taken what, for a long time, was a backwater and not a sexy position, and made it very public and shown how much it impacts people on a daily basis,” says Geoffrey Anderson, president and CEO of Smart Growth America. “It’s really changed the view of how prominent and how important these positions can be, and it opens it up to folks who think about things in a different way."

Not everyone has been happy with that departure from the status quo. In Chicago, aldermen have had mixed responses to Klein’s emphasis on bike lanes, and there was a sense that he was focused more on big-picture ideas than the nitty-gritty. "Sometimes there was a lack of communication, because you're looking at a commissioner who was looking big-picture all the time, and we as aldermen are always focused on our own individual wards," Alderman Anthony Beale, chairman of the City Council Transportation Committee, told the Chicago Tribune. "I just think he just saw that it might be time for him to depart the city of Chicago." (Klein, for his part, says he wasn’t forced out and is moving back to Washington, D.C to be close to friends and family. His wife stayed there while he worked in Chicago, and his sister and most of his close friends are also in the Washington area as well.)

Sadik-Khan has had her critics in New York. The New York Post calls her the “psycho bike lady;” Brooklyn Borough President Marty Markowitz calls her a “zealot,” and mayoral front-runner Bill De Blasio called her a “radical.” The bike lanes she's built have been subject of lawsuits. The New York Times chronicled a controversial technique used by the administration -- and in particular the transportation department -- to launch projects as “pilots” as a clever way to cut through red tape and escape the typical city review process.

Schwartz, who served as New York City’s traffic commissioner in the 1980s, is a fan of Sadik-Khan’s work but say the shift away from an car-focus has caused tension within her department. “In New York City, some of the hardcore traffic engineers felt like it was the lunatics running the asylum – they used that term to me,” Schwartz says. “Many of them have retired. It’s not the kind of DOT where a hardcore traffic engineer, a traditional highway designer, would feel very welcomed.”

But both Klein and Sadik-Khan have been unapologetic about their techniques, essentially arguing that transportation policy in their cities and elsewhere have unreasonably favored cars for decades, even though that’s not the most efficient way to move people. Moreover, they say, everyday residents of dense, urban cities don’t want to live in a community dominated by automobiles and are demanding alternatives. They say they're responding to the market demands. “We really didn’t have a choice,” Sadik-Khan told Governing earlier this year of the rapid pace of her work. "Our streets had been in suspended animation for 50 years.”

It’s not entirely clear what either of them will be doing in the next phase of their career.There’s been speculation that Sadik-Khan could go into business with Bloomberg’s planning director, Amanda Burden, with whom she works closely. Meanwhile, some advocates hope she could get Klein’s old job or take on an even bigger challenge, with car-centric Los Angeles recently getting a vacancy at the top of its transportation department.

Klein, meanwhile, says he’s interested in starting his own new venture of joining a startup that provides some sort of service to cities, likely involving technology and transportation.

Transportation observers say the ultimate testament to both Klein and Sadik-Khan, counterintuitively, will be whether New York and Chicago residents don’t notice much change following their departure. Naparstek, of MIT, says both of them have left behind policies that will continue even in their absence, and Sadik-Khan's department in particular worked to rewrite the “genetic code” of the transportation department by changing the standard language in RFPs and contracts so that road design incorporates pedestrian and bike use.

Moreover, he says, residents of those cities have signaled they like the new direction of those departments, and the demand for a pedestrian-focused approach will continue. “The change we've made is sustainable change that will be there for decades to come," Klein says. "I don't need to be there to cut every ribbon on every project I started."