The full study , part of the FCC’s efforts to beef up wireless subsidies ahead of fifth-generation (5G) deployments, states that FCC engineers measured real-world network performance across 12 states. Staffers conducted a total of 24,649 tests while driving more than 10,000 miles.

But just how bad is the disconnect? A new FCC study released this week suggests that wireless carriers may be lying about mobile coverage 40 percent of the time or more.

If you head to any major wireless carrier website, you’ll be inundated with claims of coast to coast, uniform availability of wireless broadband. But, as countless studies have shown , these claims usually have only a tenuous relation to reality, something you’ve likely noticed if you’ve ever driving across the country or stopped by mobile carrier forums .

A new FCC study confirms what most people already knew: when it comes to wireless coverage maps, your mobile carrier is often lying to you.

“Only 62.3% of staff drive tests achieved at least the minimum download speed predicted by the coverage maps—with U.S. Cellular achieving that speed in only 45.0% of such tests, T-Mobile in 63.2% of tests, and Verizon in 64.3% of tests,” the FCC said.

And while carriers have historically claimed they offer faster 4G LTE service to the vast majority of the country, the FCC found that wasn’t actually true either.

“Staff was unable to obtain any 4G LTE signal for 38% of drive tests on U.S. Cellular’s network, 21.3% of drive tests on T-Mobile’s network, and 16.2% of drive tests on Verizon’s network, despite each provider reporting coverage in the relevant area,” the agency said.

Despite claims to the contrary, the US has never really had a solid grasp on where broadband—be it wireless or fixed—actually exists. The FCC historically hasn’t done a good job confirming telecom speed or coverage claims, something reflected by the FCC’s $350 million broadband map, which critics say all but hallucinates broadband availability and speed.

Big telecom has also lobbied to prevent efforts to improve broadband mapping, wary that more accurate maps will only highlight the lack of competition and coverage in many areas. Industry has also fought tooth and nail against efforts to include pricing in said maps.

So why is the Ajit Pai FCC—with a history of cozying up to the whims of major carriers—suddenly changing its tune? As states vie for their slice of billions in looming rural wireless deployment subsidies, Senators have started to get irritated by the fact we don’t actually know where wireless is, making it hard to know which areas need the most help.

At an FCC oversight hearing last year, Montana Senator Jon Tester said the FCC’s broadband maps “stink,” adding that "we've got to kick somebody's ass" and fix the problem.

In short the backlash to the government and industry’s dysfunction has become so obvious, even the industry-friendly FCC has acknowledged that something needs to be done about it if taxpayers are going to keep footing the bill.

“Inaccurate data jeopardize the ability of the Commission to focus our limited universal service funds on the unserved areas that need the most support,” the FCC said, noting it would try harder to ensure subsidies are based on real world data.

Unfortunately data suggests that telecom subsidies can only do so much. The government historically hasn’t done a great job ensuring these funds are spent in a way that benefits US consumers, who pay some of the highest prices for mobile data in the developed world thanks to revolving door regulators, relentless consolidation, and a lack of sector competition.