Congress has finally passed a long-term extension of the highway bill, ending what had been a protracted, partisan struggle. In the end, there was little debate about the need to approve the bill — the country is in dire need of infrastructure repairs that will only become more costly if they are delayed, as both Democrats and Republicans have recognized, and a fully funded bill that is in place for the next two years will preserve and create millions of jobs.

But there should be plenty of discussion about how to ensure that transportation spending in the coming years also encourages innovations that will help overcome the one-person, one-car policy — which assumes every American wants to drive a car — at the heart of the highway legislation. Instead of focusing on just driving, we need to concentrate on mobility and creating better ways for people to navigate metropolitan centers.

As things stand now, the assumption that transportation policy and highway policy are essentially the same distorts the picture in favor of simply facilitating more and more driving, which carries enormous financial and environmental costs and takes a particular toll on the ability of our major cities to remain vibrant economic centers.

According to a Texas A&M University study last year, the delay endured by the average commuter has been steadily rising, up to 34 hours a year in 2011 from 14 hours in 1982. The study estimated the cost of congestion at $100 billion a year, nearly $750 for every commuter. By 2015, the cost of gridlock will rise to $133 billion, more than $900 for every commuter, and the amount of wasted fuel will jump from 1.9 billion gallons to 2.5 billion gallons.

Congestion is also becoming a bigger problem outside of rush hour, with about 40 percent of traffic delays occurring during midday and overnight hours, creating an increasingly serious problem for businesses that rely on efficient production and deliveries. All this is a high price to pay considering that cars are parked and idle about 95 percent of the time. Yet our federal transportation policy implicitly assumes the number of cars on the road will continue to grow each year.

There is plenty of evidence to challenge such assumptions. While millions of Americans may still be stuck in traffic, the transportation habits of the rising millennial generation of 18- to 34-year-olds are fast on the move. They are increasingly forgoing car ownership, and because they have come of age in a world of social and digital media that allows them to stay connected to friends and family they drive much less than past generations.

Zipcar’s annual survey of driving habits confirms these trends: Millennials are much more likely than other age groups to reduce their driving for economic as well as environmental reasons. Where other generations once saw cars as symbols of freedom, a stunning 80 percent of millennials now see them as a financial burden. Given the volatility of gasoline prices and the fact that the average price of a new car now exceeds half of a typical family’s income, it’s not hard to see why. Some two-thirds of millennials now say they would use public transit if it was available. There is no reliable public transportation in many parts of the country, however, and merely extending highway policies that emphasize driving as the sole form of transportation won’t change that.

Congress needs to think in terms of a balanced, long-term transportation policy that reflects changing priorities rather than reinforcing antiquated thinking and the unsustainable proposition that we can pave our way out of our transportation problems. But the new transportation bill actually cuts funding for bike and pedestrian infrastructure. (It’s doubtful many members of Congress took note that Washington, D.C. ranked fourth in a May survey of the top 50 bike-friendly cities by Bicycling Magazine, the result of establishing bike-sharing programs and adding 11 miles of bicycle lanes in recent years.)

A new policy that sets mobility and livability as explicit goals — as forward-thinking cities like Chicago and San Francisco are discovering — will help rebuild communities, reduce pollution, improve quality of life and allow cites to do what cities do best: spark innovation.

But whatever the new policies or payoffs may be, this much is clear: Every time Congress extends the old highway bill into the future, it merely puts our country further into the past. National policy ought to transport us toward tomorrow instead.