The FCC recently announced a program that would task the US carriers with performing drive tests to verify that their coverage maps are accurate, but this week two of the operators came out against that plan.

AT&T and T-Mobile both submitted filings with the FCC this week arguing against the FCC's plan to have carriers confirm their coverage maps with on-the-ground tests. AT&T estimated that it would cost $45 million to drive test 25% of the square kilometers of its 4G LTE network, saying that that money could better spent on deploying 5G (via Ars Technica).

"Requiring that all carriers conduct such nationwide drive tests, especially on a regular basis, is simply too costly especially at a time when investment in 5G deployment is a top national priority," AT&T argued.

T-Mobile made a similar argument in its filing. The magenta carrier said that on-the-ground network testing is "highly complex, time consuming, and expensive" and that that money would be better spent investing in T-Mo's network in rural parts of the US.

"Drive tests and similar procedures are extremely expensive and burdensome to conduct, especially at the scale needed for a statistically significant sample of a nationwide network," said T-Mobile. "A blanket requirement to perform regular on-the-ground testing will force providers to spend millions of dollars each year on tests, resources that would be better spent investing in our network and deployment in rural America."

Late last year, the FCC accused T-Mobile, Verizon, and US Cellular of misrepresenting their coverage maps. T-Mo only provided the minimum download speed predicted by coverage maps 62.3% of the time, the FCC said, and the agency was unable to get a 4G LTE signal in 21.3% of the locations where T-Mobile said it had 4G LTE available.

Now the FCC has submitted a plan as part of the Broadband DATA Act that would foce US carriers to verify the accuracy of their coverage maps using on-the-ground testing, including both mobile and stationary testing while outdoors.

It remains to be seen if the US carriers will actually be forced to perform these drive tests, but the plan is being supported by the California Public Utilities Commission. The CPUC performed its own drive tests in 2019 and found that the carriers' submitted maps overstated their coverage. Below you can see a comparison showing how the CPUC's drive test of one carrier's network differs from the map submitted by that operator.