"They're sprouting up like Texas wildflowers," Vivian Ho, a health economist at Rice University in Houston, told Modern Healthcare last year. "Everywhere you drive in upper-middle-income Houston, you're seeing emergency rooms on every block."  

Emergency care is particularly important in the Lone Star State, which has the dubious distinction of having the highest uninsured rate in the country. More than 20 percent of state residents lack insurance, meaning they are more likely to show up at the ER for basic medical care.   

Dr. Jane Bolin, a professor of public health at Texas A&M, told KBTX that standalone emergency rooms are particularly useful in rural areas.   

"It costs more to run a hospital in a rural area, but to have a freestanding emergency department, then I think it would provide emergency care out in those areas where they perhaps need it more than others," she said.  

However, critics contend that the facilities often purposefully avoid serving areas that are most in need of ER care.  

"They're very good at targeting areas with people with higher incomes, with good insurance," Ho told Modern Healthcare. 

This isn't the first time Texas has experimented with a model of medical care shunned by others.   

The state also has many more doctor-owned hospitals than other states, largely due to their embrace by former Gov. Rick Perry, whose own sister was a lobbyist for doctor-owned facilities.