http://healthcare.dmagazine.com/2016/05/18/are-freestanding-emergency-rooms-driving-up-costs/

In most affluent corners of North Texas, these centers have become as ubiquitous as Starbucks. They’ve sprouted near households whose families are insured through private insurance plans and sold as a boon to a community in need of emergency services. (A Texas Tribune study found that these neighborhoods have incomes 49 percent higher than the state’s average). In 2010, there were about 20 freestanding ERs in Texas. Now, just six years later, there are north of 215, galvanized by a 2009 state law that allowed them to become licensed emergency rooms.