The taxi driver taking me from Chicago’s Midway Airport to Hyde Park was unequivocal about what he thought of all the bike lanes Mayor Rahm Emanuel was installing across the city. He named an intersection and said, with his voice rising as he took a hand off the wheel and gestured outside, “I could stand all day on the corner there and not see someone on a bike.”

That may or may not be the case, but the cabbie had put his finger on at least part of the truth. Cities and towns all over the country, ranging in size from Chicago and New York to the small town I visited recently in Minnesota, are striping streets for bikes at an astonishing rate. It’s part of a sea change in how we view our streets and what they’re used for.

Long the afterthought of transportation policy, bike lanes and bicyclists are now front and center. Mayors, council members and transportation department chiefs are routinely subtracting lanes that have been dedicated to Americans’ supposedly beloved cars and giving them to people on bikes. “We’re definitely in something of a revolution here,” says Randy Neufeld, director of the SRAM Cycling Fund and a longtime cycling advocate in Chicago.

But amid these changes, few have stopped to ask whether bike lanes even work, and by what standards we can tell if they do. Street space is perhaps a city’s or town’s most valuable asset. When adding bike lanes, there are a number of goals -- sometimes conflicting ones -- that policymakers must pick and choose from, such as how many cyclists should be using the lanes, whether traffic congestion is impacted (for both cars and bikes), the amount of economic development spurred and even general population health effects.

So with that in mind, I suggest that localities jumping on the bike-lane bandwagon do the following:

First, count how many people use bike lanes, both on individual streets and citywide. Set numerical targets for cycling use. If after a number of years targets aren’t met, be ready to make serious adjustments, including sometimes removing bike lanes. Which isn’t to say that all bike lanes need to be used equally. As with streets, highways and train lines, a system of bike lanes is a network, and so the parts, even those less used, contribute to the utility of the whole. Still, there needs to be some sort of evaluation on an ongoing basis about how useful a bike lane really is.

Second, count other things beside just the people on bikes. Moving toward a more bicycle-oriented city should be part of a number of goals, including reducing obesity, increasing walking, achieving cleaner air, producing business corridor development and lowering car ownership. All these goals can and should have metrics attached to them.

Third, move toward “protected bike lanes,” which physically separate cyclists -- via a row of parked cars or plastic barriers, for example -- from dangerous car traffic. According to the advocacy group PeopleForBikes, the number of protected lanes nationwide now stands at 292, more than five times the number in 2010. Cyclists love these, but they also represent the most significant investment of street space. Cities should adopt these at a reasonable pace, recognizing that moving too fast can provoke a backlash.

Fourth, pursue legal changes, typically at the state level, that will put more responsibility for accidents, and thus for safety, on people driving cars. Countries renowned for the quantity and quality of their biking, such as Denmark and Holland, do have lots of bike paths and lanes. But cyclists there also freely mix with car traffic with a self-assurance that is startling to an American. The reason the bicyclists are so bold is that those countries and much of the rest of Europe initially place the blame for an accident between a motorist and a bicyclist or pedestrian on the motorist. It’s a standard sometimes known as “default liability.”

“Here in the U.S.A., there is still this notion that all users are equally responsible,” says Paul White, executive director of Transportation Alternatives, a cycling advocacy group in New York City. “This is a false equivalency. In Europe, they start with the premise that if you’re driving a multiton vehicle, you have more responsibility than someone who’s not because you have more capacity to inflict harm.”

To my knowledge, no American state has made this change. But reworking these legal lines is ultimately as important as painting new lines on streets. This sort of change will discourage bike lanes from becoming a kind of ghetto for cyclists. I have had drivers in Brooklyn, where I live, politely (well, not always) tell me to “get in the bike lane” when I have unavoidably had to venture out into regular traffic.

And finally, don’t forget public bike-share programs. In denser cities, bike programs have the potential to ease the clutter of privately owned bikes around lampposts, street signs and bike racks. Instead of sitting on the street for hours or days unused, a public bike is ridden several times a day. But these programs have to be cheap for the user, even if that means subsidizing them with city funding.

All in all, the move to more bike lanes and more bicycling is a great thing. Judging from its treatment in ads, television and movies, the once-humble bicycle is clearly in -- even chic. But every revolution needs some means of moderation and evaluation.