While looking up the best way to describe the aboriginal pronunciation of Uluru (/uluɻu/), I stumbled across retroflex approximants. The linked Wikipedia page states:
The retroflex approximant occurs in American English, Mandarin Chinese, Pashto, a few Brazilian Portuguese dialects ...
It then proceeds to state that red is pronounced as /ɻʷɛd/ in certain American dialects. Going by the audio sample provided on the page, I find this a little hard to imagine. The article links to another wiki on English phonology which confirms that:
Depending on dialect, /r/ may be an alveolar approximant [ɹ], postalveolar approximant, retroflex approximant [ɻ], or labiodental approximant [ʋ].
So, who in the US pronounces red as /ɻʷɛd/? How did this come about?

