If you are looking for the best mobile phone performance among U.S. cities, the winner of the category for the first half of 2017 may surprise you: It's Lansing, Mich.

And while you may have assumed that big cities would have the best mobile phone performance overall because they have plenty of cell towers and equipment, you'd be wrong. Instead, because large cities have larger populations, there are higher demands on their networks, often causing them to be slower despite the extra equipment in use.

Those are among the many interesting results of the latest Metro Rankings Report for the first half of 2017 from independent mobile analytics firm RootMetrics.

The top five cities for mobile service are:

Lansing, Mich., which ranks 117th in population Indianapolis, which ranks 32nd in population Modesto, Calif., which ranks 104th in population Chicago, which ranks 3rd in population rank Port St. Lucie, Fla., which ranks 100th in population rank

Lansing's placement was even more impressive because it jumped from the 20th spot in the previous rankings from the second half of 2016, according to RootMetrics.

The rankings for the 10 most populated U.S. cities varied, the study reported:

New York City–Current rank: 74 (Previous rank: 66) Los Angeles–Current rank: 77 (Previous rank: 49) Chicago–Current rank: 4 (Previous rank: 8) Miami–Current rank: 68 (Previous rank: 89) Philadelphia–Current rank: 59 (Previous rank: 32) Dallas–Current rank: 23 (Previous rank: 26) Houston—Current rank: 70 (Previous rank: 18) Washington D.C.—Current rank: 39 (Previous rank: 40) Atlanta—Current rank: 14 (Previous rank: 23) Boston—Current rank: 55 (Previous rank: 97)

So, what's it all mean?

Well, the first myth to be exposed is that big cities have the best mobile performance due to all of their infrastructure. The problem with that theory, says Annette Hamilton, a spokeswoman for RootMetrics, is that the extra mobile users in larger cities typically tax the networks, contributing to slowdowns compared to places like Lansing, she said.

"Think about being at a major sports venue where there are lots of people and things slow down," said Hamilton. It's the same kind of congestion in larger cities.

"If you look at cities like New York City, it's a special case because a lot of buildings there are older" and are built from materials where it is harder to get a mobile connection, she said. "Signals don't go through those older buildings as well."

Chicago, though, the nation's third-largest city by population, came in fourth in the latest RootMetrics rankings, most likely due to improvements in the area's mobile infrastructure, said Hamilton.

"We will sometimes see cities light up year over year" and climb the rankings. "That was something we saw in Chicago a of couple years ago as well. What we came to discover at the time in news articles is there were some heavy investments in new technology, almost being piloted there. Chicago is almost a rock star in performance."

In the future, similar trends are expected, she said, as other cities begin to see rollouts of 5G network infrastructure pilots, which will bring more speed boosts in specific cities.

"You'll start seeing little pockets," said Hamilton.

Also seen in the rankings are drops for cities like Austin, Texas, where mobile performance has fallen from 25 in the last survey to 72 this time, due largely to an increase in population without similar upgrades in the networks so far, she said.

"What that tells me is that's probably a congestion problem," said Hamilton. "They will fix it, but they just haven't yet. If you get a bunch of people moving in sometimes that takes a bit to catch up."

RootMetrics has been conducting its mobile performance rankings for the last several years. The rankings are based on an average of the RootMetrics scores of all four major U.S. networks—AT&T, Sprint, T-Mobile and Verizon—in specific metro areas, weighted by the estimated national percentage of subscribers for each network. This means performance scores from networks that have more customers are weighted heavier than scores from networks with fewer subscribers.

The scores are based on overall performance testing, which includes a combination of reliability and speed results from data, call and text testing, as well as network reliability testing, which looks at reliability performance across data, call and text testing. Also included is network speed testing, data reliability testing, call testing and text testing.