Why do we fail? Chris Ward, the former head of the Port Authority, offered this provocative question at the start of Transportation 2030, the sequel to Manhattan Borough President Scott Stringer’s 2006 transportation conference.

Considering how much progress has been made toward sustainable transportation since 2006, it seemed like an odd question at first. But a closer look shows that nearly all of that progress has been made by one agency: NYC DOT.

DOT has re-designed and re-engineered miles of city streets for safety. DOT has created acres of new public spaces, a new urban art program and programs like Summer Streets and Weekend Walks that have helped redefine the way New Yorkers see their streets. The agency has given people better transportation options by installing 260 miles of bike lanes in the past four years alone, and launching three new Select Bus Service routes with the MTA.

Aside from SBS, the MTA’s recent innovations and improvements for transit riders have been few and far between: the addition of real-time arrival signage in 153 stations, real-time bus information on a few pilot routes, and in-station transfers at a handful of stations. The positive changes have been overwhelmed by severe service cuts and round after round of fare hikes.

It is tempting to say the difference between the effectiveness of the DOT and the MTA is due to budget alone. The MTA has had to cope with a continuing budget crisis brought on by the economic collapse, repeated Albany raids, and a crushing debt load. But Ward’s answer might be more telling: “Wars are lost when the people fighting them lose the capacity to see the outcome they desire. Runners don’t stop running because they are tired, they stop when they don’t think they’ll be able to reach the finish line.”

The Bloomberg administration was already laying the groundwork for its long-term sustainability plan, PlaNYC 2030, during Stringer’s first conference in 2006. PlaNYC laid out an ambitious set of goals to meet the challenges posed by the city’s growth and simultaneously improve the city’s environmental sustainability. Shortly after the Mayor announced PlaNYC in 2007, he appointed Janette Sadik-Khan as the new Commissioner of NYC DOT, to ensure that the plan’s meaty transportation goals would be met. Building on PlaNYC, Sadik-Khan worked with her staff to create a strategic plan with even more concrete goals, many of which were entirely within the power of DOT to implement. The vision set forth in Sustainable Streets has helped guide the agency and encourage its staff to press ahead.

Stability and excellence in leadership matter. The city has had one mayor since 2006 and DOT has had essentially one commissioner (though Iris Weinshall spoke at Stringer’s 2006 conference, it was already clear to most insiders that she was on her way out). In contrast, the state has had three governors and the MTA has had four different executives since the 2006 conference.

The MTA has struggled through these repeated changes in leadership. Neither Governor Andrew Cuomo nor incoming MTA Chair Joe Lhota have articulated much vision beyond performing triage on a hemorrhaging budget. Even Jay Walder, the previous MTA chair who made some crucial progress at the agency, articulated his policy vision in a document entitled “Making Every Dollar Count.”

Both the MTA and the DOT are enormous agencies. Some would liken them to cruise ships. It takes strong, consistent leadership and a clearly articulated vision to steer these ships and to keep them — and the staff who comprise them — on course. Politics will always be challenging, and it seems like budgets will be tight for a long time to come. How do we avoid the failure that Ward talks about? The government executives and transportation leaders who can create a strategic vision for getting things done even in trying economic times are the ones who will not just finish the race, but win it.

Dani Simons has worked as communications director for the Institute for Transportation and Development Policy and Transportation Alternatives, and is the former director of strategic communications for NYC DOT.