One of the most insightful questions of the 2013 campaign season came two weeks ago, when WNYC’s Brian Lehrer asked Bill de Blasio if he considered transportation policy “one of his tools to fight inequality.”

De Blasio, who overwhelmed his opponents this election cycle by appealing to New Yorkers’ sense of economic fairness, gave this response:

Transportation determines opportunity, livability, business climate. For many people, the absence of affordable transportation, in outer-borough locations especially, constrains their opportunities.

Those two sentences are an excellent distillation of why de Blasio is viewed with a mixture of hope and trepidation by New Yorkers who care about livable streets.

You can tell the mayor-elect has a command of the issues. He gets that access to transit is linked to economic opportunity. Maybe he’s even taken a good long look at the Pratt Center’s maps showing the lengthy commutes that low-income New Yorkers grind through every workday.

And yet, he didn’t actually say “transit.” Intentionally or not, sticking to the neutral phrase “transportation” signaled an absence of commitment. In two sentences, de Blasio showed off his policy chops while managing to avoid the appearance of taking sides.

De Blasio’s policy book laid out ambitious goals for streets and transit, including pledges to adopt a zero tolerance stance toward traffic deaths and to allocate more street space to transit by implementing at least 20 BRT routes. By and large, though, these promises have stayed buried in campaign documents. While de Blasio stated his support for bike lanes and pedestrian plazas in interviews, it all seemed to carry less weight after the candidate said during a televised debate that “the jury’s out” on the major Midtown street reclamations.

Safe streets and quality transit never did make it into his stump speech. But once de Blasio begins governing the city, the management of New York’s streets will be one of the few areas in which he can make a noticeable mark on his signature issues — inequality and affordability.

The de Blasio campaign’s top policy proposal — raising income taxes on wealthy New Yorkers to fund universal pre-K — depends on Albany. If he pulls it off, the change could be profound, but it will take a generation for the effects to fully play out.

New York City’s streets, meanwhile, can be made more equitable while de Blasio is still mayor. Most households in New York (54 percent) don’t own cars, and households that do own cars earn more than twice as much, on average, as households that do not. Our streets, however, are designed to favor the privileged: A few well-off people in space-hogging SUVs can delay hundreds of less affluent people riding the bus. This is one thing that the mayor of New York has the power to change, if he wants to.

It takes a lot of vision and willpower, not a lot of money, to turn traffic lanes into transitways. Protected bike lanes cost a pittance and can be built in a matter of days. Every step the mayor takes to make these modes of travel more viable not only helps less affluent New Yorkers who already don’t have cars, it lets more New Yorkers shed the tremendous cost of owning, fueling, insuring, and maintaining a motor vehicle.

Another powerful reform Mayor de Blasio could make on the affordability front would be to end the city’s minimum parking requirements. This misguided policy foists the costs of parking onto developers whether they want it or not, inhibiting the supply of housing and driving up the cost of living in NYC. Re-orienting NYC’s zoning code to prioritize the housing of people, not cars, is within the mayor’s control. It would be a tough fight that challenges car owners’ perception that plentiful off-street parking helps them land coveted, free curbside parking — the Bloomberg administration barely touched the issue in 12 years.

Some of the world’s great progressive mayors made their names by using transportation policy as a lever to reduce inequality. It was “Red” Ken Livingstone who enacted London’s congestion charge in 2003, creating immediate and lasting improvements to the city’s bus system. Bogota’s world-class BRT network and extensive bikeways arose from Mayor Enrique Penalosa’s conviction that the allocation of streets and public space is deeply enmeshed with issues of social equity. In his words, “A bikeway is a symbol that shows that a citizen on a $30 bicycle is equally important as a citizen in a $30,000 car.”

Both faced intense skepticism and opposition to their ideas before they were vindicated by demonstrable success. And today that’s what has to be gnawing at New Yorkers who want to reform the status quo on our streets: Will Mayor de Blasio withstand the skeptics and opponents who’ll inevitably line up against the transportation proposals in his policy book? How will he react when merchants object to the loss of parking to make room for a busway? Will his emphasis on process yield real improvements to New York’s community board system, which is structured to favor stasis and the car-owning class, or will it become an excuse to shelve ambitious street redesigns that encounter resistance?

There’s more on the line than the streets of the nation’s largest city. Michael Bloomberg may not be known as a progressive, but his DOT, led by Janette Sadik-Khan, has sparked a wave of innovation in other American cities. More than any other public agency, NYC DOT is responsible for popularizing a multi-modal, complete streets approach to urban transportation — the same ideals espoused by the Obama administration. De Blasio’s dominant victory is being hailed as a sign of things to come, nationally, for the liberal wing of the Democratic Party. But on transportation, it’s an open question whether New York will remain a beacon for progressive policy under de Blasio. It wasn’t that long ago, after all, that he called Sadik-Khan a “radical.”

One cause for optimism is that de Blasio will be working with a City Council that seems increasingly aligned with the local livable streets movement. Veterans including Melissa Mark-Viverito and Brad Lander — who championed street redesigns in their districts — are de Blasio allies and may assume powerful leadership positions (Mark-Viverito is rumored to be de Blasio’s preferred speaker candidate), while newcomers like Carlos Menchaca, Antonio Reynoso, Vanessa Gibson, Ritchie Torres, and Mark Levine have shown more enthusiasm for overhauling their districts’ streets than the council members they replaced.

With an engaged advocacy community pressing for change, the pieces should be in place to keep making progress toward more humane and equitable streets. The candidate with the best livable streets platform won. New Yorkers can’t let Mayor de Blasio forget those promises.