"Verizon has done well with the quick deployment of their AWS network," RootMetrics President Bill Moore said in an interview. "A year ago AT&T was speeding up, while Verizon was slowing down. There's always an ebb and flow as new networks eventually carry more load."
In the first and second halves of last year, Verizon was behind AT&T in network speed, according to RootMetrics's previous studies. In the first six months of 2014, Dallas-based AT&T placed second in all six categories tested by the researcher, bar text messaging.
While T-Mobile, the fourth-largest U.S. wireless provider, finished last or second-to-last in all the categories measured by RootMetrics, the carrier overtook AT&T to place second- fastest behind Verizon in city locations.
The improvements in speed suggest AT&T and Verizon, the two dominant carriers in the U.S., will have to work harder to prevent consumers moving over to the smaller carrier.
"T-Mobile has gotten a lot of attention with their marketing and they came out second to Verizon in metro speeds," Moore said.
The Bellevue, Wash.-based carrier has been recruiting subscribers with cheaper plans and phone financing. T-Mobile added more customers than analysts estimated in the second quarter and raised its forecast for subscriber growth, projecting it will add as many as 3.5 million postpaid subscribers this year.
Its wireless performance was superior to that of Sprint, the third-largest carrier, according to RootMetrics. Sprint, based in Overland Park, Kan., finished last in four of the six categories, ahead of T-Mobile only in reliability and text performance.
SoftBank Corp., majority owner of Sprint, withdrew from a plan this month to boost the struggling carrier by merging it with T-Mobile. Instead, Sprint Chairman Masayoshi Son brought in Marcelo Claure, founder of Brightstar, a phone distributor, to replace Dan Hesse as CEO, in an effort to stop customers leaving and revitalize the business.
Sprint Monday said it will double the amount of data available for its shared plans. Customers who switch to the carrier can have as many as 10 mobile-phone lines share 20 gigabytes of data for $100 a month. That compares with an offering from T-Mobile that provides four lines with 10 gigabytes of data for the same price.
"We aren't counting out Sprint," Moore said. "It's an ever-changing game."
For its research, which it conducts biannually, RootMetrics, based in Bellevue, Washington, collected more than 5.6 million test samples in all 50 states of the U.S.