CTIA and CostQuest Associates recently teamed up to find out how comprehensive mobile broadband coverage is in the United States. In a 3-month survey, CostQuest’s study concluded that roughly 23.2 million Americans live in areas without access to mobile broadband access and that the investment to bring it to all Americans will be substantial. The company estimates it will cost roughly $22 billion.

In the study, CostQuest measured the current deployment of EV-DO and HSDPA and determined the geographic and population gaps in full coverage. The research company then estimated the infrastructure enhancements and new construction necessary to extend both broadband mobile service technologies to those geographic areas and populations lacking coverage, as well as the costs of making those investments.

The study also concluded that 42% of U.S. road miles don’t have access to any 3G mobile broadband service. In order to achieve full 3G mobile broadband coverage with both technologies, the study estimated that carriers must build approximately 16,000 new towers and enhance approximately 55,000 existing towers with HSDPA and EV-DO equipment.

The data and analysis in the study provide a baseline for policy discussion, and CTIA submitted the data to the FCC last month.