Why does Google say that the driving distance between O'Hare International Airport (ORD) and Downtown Chicago is 20.5 mi and 1 hour 17 minutes?
It doesn't make sense that a 20-mile drive will take me an hour 17 minutes. Am I missing something?
Because that's about how long it takes at this time of day during the week.
On that route, in addition to the almost-always very heavy traffic (shown by the red areas on the Google Maps route) there's also frequent construction zones, which are often lane reductions to boot.
Too, this moment on Friday is right in the middle of "rush hour" (a phrase that hasn't been accurate in perhaps half a century). Adjust the Google choices to show a departure tomorrow (Saturday) at the same time, or in the middle of the night on a Tuesday, for instance, and the driving time reduces.
Heavy traffic in busy cities is normal. It would be similar if you were trying to get in and out of NYC or Boston or San Francisco at this hour. Is this news?
The smarter way is a perfectly nice train that runs from O'Hare to downtown Chicago straight shot: $5. It'll let you off blocks from anywhere in the Loop, or you can get an Uber at that point.
When you're in a city like this, a car is a huge impediment, an albatross around your neck. Paying hundreds of dollars to rent a car, plotz in hellscape traffic, pay to store it in a downtown parking garage, risk parking tickets if you're not savvy about parking in cities, etc. -- that's a lot of money and time sunk. At least evaluate transit.
I always use transit in NYC, Philly, DC, Chicago and Toronto. Never driven in any of them, never expect to. I'm also fond of staying in hotels right next to suburban train stations for 1/2 to 1/3 the nightly cost of a downtown hotel.
You may also have "Avoid Tolls" selected in your Google Maps settings, as that route is using surface roads (River, Harlem) instead of the expressways for the first half of the trip. But, given the time of day and typical delays/accidents on either expressway routes (I90, I294/290) it's possible that was the fastest option.