In my .bib archive I have the next reference:
@misc{Quora,
title = {In optimization, why is Newton's method much faster than gradient descent?},
howpublished = {\url{https://www.quora.com/In-optimization-why-is-Newtons-method-much-faster-than-gradient-descent/}},
note = {Accessed: 2015-06-07},
author = {Carlin Eng}
}
and the result in the pdf is

I suppose that is for the long url "In-optimization-why-is-Newtons-method-much-faster-than-gradient-descent/" without any slashes.
I'm using \bibliographystyle{ieeetr}

-as a allowable linebreak point. See, for example, the answer at http://tex.stackexchange.com/questions/102673/manually-url-linebreak-with-biblatex and the macros\UrlBreaksand\UrlBigBreaks– Steven B. Segletes Jun 23 '15 at 19:32\documentclass{...}and ending with\end{document}. – egreg Jun 23 '15 at 19:59