For the two toll lanes on freeways in Los Angeles County, you need FastTrak. Hertz does not provide ANY vehicles at LAX with FastTrak.
https://www.hertz.com/rentacar/produ...Splatepass.jsp
There are VERY few toll highways or lanes west of the Rockies and most can be easily avoided (I have never paid a toll in California other than 2 bridges in SF). In California, toll bridges in the San Francisco Bay area would be your biggest concern.