Washington ? With the exploding popularity of smartphones, wireless laptops and, if Steve Jobs has his way, tablet computers, it’s fast becoming a wireless world. But the breakneck growth of all things wireless is threatening to cause a traffic jam — of the airwaves that deliver calls, Web searches and video to those data-hungry devices.

Left unchecked, it could eventually mean more dropped calls, slower service and a lot of frustrated customers. Recent complaints of dropped calls and slow connections by iPhone users on AT&T’s networks in San Francisco and New York foreshadow a potentially widespread problem.

Now federal regulators are working to head off what they call a “looming spectrum crisis” — a severe shortage of the wireless frequencies that deliver data and allow smartphones to perform all the tasks people expect. A proposal from the Federal Communications Commission is expected next month.

The electromagnetic spectrum that carries these transmissions is highly valuable and allocated by the government to businesses that often pay for their slice. That complicates any effort to shift it from one use — such as over-the-air TV broadcasts or satellite TV — to wireless providers.

The problem is one of basic supply and demand. More and more Americans are buying smartphones and using them not only to make calls but also to watch YouTube videos, share pictures, surf the Web and download books, among a litany of other applications on the horizon. But the bandwidth to deliver data for all those functions is limited.

At the end of 2008, 34 million mobile subscribers in the United States accessed the Internet using their cell phone, according to Forrester Research, a technology market research firm. That number is projected to grow to 106 million by 2014.