This data comes from EV drivers who use PlugShare, a mobile and web application developed by Xatori, a technology company focused on building innovative software for connected cars. PlugShare has grown its nationwide charging network to more than 100,000 users and 11,000 charging stations across the U.S. When it started up, there were only 500 charging stations in the app.
The mobile app assists drivers in finding the best charging options nearby and also collects information on EV behavior, hence the user/driver patterns and top EV-ready cities previously mentioned. A new app, GreenCharge, is an iOS app that simplifies the driver experience and can connect with a Nissan Leaf, Chevy Volt or Toyota Prius Plug-In.
Ironically enough, the San Francisco Bay Area and Seattle are behind Dallas and Nashville at numbers four and five, respectively. Los Angeles doesn't even crack the top 10. The article doesn't define the methodology for what city makes the EV-ready city cut, or what it actually means. As for Portland, that's got to be the city in Oregon and not the one in Maine.