America’s fast-growing cities are experiencing housing shortages. It’s a topic I’ve covered in my last two columns, focusing mainly on the emerging YIMBY (“yes in my backyard”) movement and how NIMBYs, or the “not in my backyard” contingent, have impeded efforts to build new construction that promotes density. And while both sides agree that more construction is needed, NIMBYs tend to ask an essential follow-up question: What about traffic?

This question, while alluding to roads, often taps into a broader sentiment that the local services -- schools, hospitals and sewer pipelines, among other things -- are already overburdened in many cities. And the people who think this way have a point.

Take San Francisco, where I’m currently living. More than 864,000 residents live within 47 square miles, making it extremely dense by U.S. standards. Another 230,000 people commute into the city for work. If housing were built to accommodate everyone who wanted to live here, the population could exceed 1 million.

But San Francisco is already struggling to house its current population. The Bay Area has added more than 600,000 new jobs since 2010 but created only about 60,000 new housing units. If another quarter million moved here, it would bring serious challenges. The roads are already jammed, especially around downtown. Buses and trains are packed to the brim. And libraries, parks and other services are strained. Most urbanists agree that adding more density would actually help matters. “Theoretically,” says Rachel Quednau, an analyst for Strong Towns, which advocates for fiscal solvency in cities, “if a bunch of new people are coming in and you’re building new housing, then they should be contributing a tax base that will support those new services.”

That’s not always the case, though. Los Angeles, for example, is the nation’s most densely populated urbanized area and yet has the nation’s largest homeless population, the worst congestion and numerous other service failures. NIMBYs have a point when they ask why a city such as Los Angeles should pack in more people when previous decades of population and revenue growth apparently worsened these problems -- and might yet worsen them more.

Of course, cities aren’t going to stop growing, and we wouldn’t want them to. Urban density is both culturally and economically enrichening. But the strategy for managing density could use improvement. At the administrative level, cities need more flexibility. Tight regulations squelch both private- and public-sector innovations that would enhance dense urban living, such as ride-sharing, congestion pricing, transit construction, housing for the homeless and much more.

To their credit, NIMBYs want to ensure that change doesn’t bring chaos. Density advocates thus need to think long and hard about which practical infrastructure improvements should go alongside their grand housing visions, so that mobility and services aren’t compromised. That is the only way political support will emerge for adding the housing that cities so desperately need.