From Mark Sullivan … 3G/4G Performance Map: Data Speeds for AT&T, Sprint, T-Mobile, and Verizon:
Click the map for our neighborhood-by-neighborhood speed test results, as well as Web page and video load times, at each of our 127 testing locations in 13 cities.
How to Use the Map: We tested wireless service in 13 cities, and in each city we tested in ten locations. The map below displays our test results for each location.
To zoom in on a city, use the navigation controls at the upper left of the map, or click repeatedly on or near the group of map pins.
Click the blue pins to display the results. You'll find download and upload speeds (in megabits per second), network latency (in milliseconds), and Web page download and video stream times (in seconds) for both the 3G and 4G services of the four national wireless carriers.
View 3G/4G Wireless Tests in a larger map