Living in Rochester, I invested in a capacitor type dash cam. This requires power from your car, but the benefit is that it holds up much better to extreme hot and cold temperature versus battery powered dash cams.

Im currently running a low end BlackVue dash cam and its great. It is well worth the $150 for the piece of mind, hides well behind the rear view mirror, and it has parking monitoring.

The more expensive ones have wifi so you dont have to remove the SD card to unload footage, and they sell a two-channel option if you wanna watch your rear too.

If you want to go the dash cam route, i dont recommend cheaping out, especially in LA.

Edit: quick google search. I got a 64Gb version of this. https://www.amazon.com/gp/aw/d/B01HFFQIHG/ref=mp_s_a_1_1?ie=UTF8&qid=1519133772&sr=8-1&pi=AC_SX236_SY340_FMwebp_QL65&keywords=blackvue+dr450&dpPl=1&dpID=31ngYvGsE5L&ref=plSrch

Sorry for the formatting, ignorant and on mobile.