(Telecompaper) T-Mobile US has come top among US mobile operators in speeds tests by Open Signal and Ookla's Speedtest in the first half of 2018. The mobile operator averaged 21.6 Mbps in the Open Signal 4G tests in Q2, up 2 Mbps from six months earlier, and reached a score of 27.86 over the first half on Speedtest. Verizon came second in the tests, with average speeds of respectively 20.6 Mbps and 26.02. AT&T was third with an average 15.1 Mbps on Open Signal and 22.17 on Speedtest. Sprint reached respectively 14.5 Mbps and 20.38.