Convert xml to json and format [duplicate]

This question already has an answer here:

• XML <-> JSON conversion in Javascript 4 answers

I am using the CTA API (http://ift.tt/1sNdvQI) and the responses are xml. I'd like to convert to json after my fetch in a backbone collection. The response looks like this:

<?xml version="1.0"?>
<bustime-response>
<route>
    <rt>1</rt>
    <rtnm>Bronzeville/Union Station</rtnm>
    <rtclr>#336633</rtclr>
</route>        
<route>
    <rt>2</rt>
    <rtnm>Hyde Park Express</rtnm>
    <rtclr>#993366</rtclr>
</route>        
</bustime-response>

I'd like it to look like this:

[
  {
    "rt": "1",
    "rtnm": "Bronzeville/Union Station",
    "rtclr": "#336633"
  },
  {
    "rt": "2",
    "rtnm": "Hyde Park Express",
    "rtclr": "#993366"
  }
]

What's the best way to do this?