Chicago can be really bad.. like 3 hours to drive 20 miles down I-90 from ohare on a friday afternoon at 3:30 pm.
However, I was in downtown LA a couple weeks ago and it could take easily 20 minutes just to grab an uber that's sitting a couple blocks away during rush hour. Also even though I was only there 4 days, sure enough during rush hour there was a high speed police chase and it shut down multiple blocks, which made our hotel shuttle buses sit for 20 minutes before they could scoot over to the curb where they could let us off to walk if we chose to.
Also let's talk about parking in LA. In Chicago, sure you could pay about $25-30 to park for the day if you drive in. In LA, you pay $45 to park at the hotel YOU'RE STAYING AT, then another $20 to park at the conference center, plus whatever other parking garage you might have to park if you explore the city (plus whatever the rental car is).
It's no wonder why people uber. We were able to nearly anywhere (group of 3) for $3-$5 ($30 to bring all of us from downtown LA to the airport).