As long as the car can see the sky the GPS should work. Most navigation systems in cars even have the ability to "guess" while you are driving in tunnels based on your last position and speed. Tall buildings or tall trees also affect the signal, but not too badly. The maps are built in to the car, but the phone needs the cell signal to find its maps.

There are on-phone maps available, I use Sygic Navigation.

 

The navigation works anywhere. The maps are in an SD card near the radio. If you are in an extreme remote area you may not get the traffic data but I highly doubt there is any traffic in that situation. My frustration with in car Nav is that they won't let you enter an address except when completely stopped. That's why I've had to use my phone instead when I change where I'm going at 70 mph on a highway.

The best thing to do is save all of your popular addresses and then you can 1 click choose them.

 

What I don't like about the nav on my Touring is you can't name a destination! As someone with lyme brain issues, I look at addresses and they don't mean squat!

 

Most GPS require addresses, so I tend to write down addresses of locations I plan to visit or save it on my phone to type in later.

 

Thanks for all the replies.

I just took the Niro to Mt. Mitchell in western NC for camping and the GPS worked great.

Some GPS quirks I discovered:
- Our leader gave us all GPS coordinates as well as addresses to the destination. The GPS coordinates worked fine, however when I tried to save the GPS coordinates I couldn't pick a title for the shortcut. The title of the shortcut was the GPS coordinates itself which isn't very useful. I couldn't name the shortcut something like "Pisgah Campground". It would be nice to name the GPS coordinates especially since we used like 3+ coordinates for the entire trip.

- Inputting GPS coordinates is fine, but not very fast. The "-" and number keys are on different keyboards.

- I think the biggest advantage the iPhone has over the car GPS is the ability to input a destination while the car is moving. Sometimes decisions are made on the fly and the car GPS is useless if you need to change destinations while on the road.

- I used my iPhone navigation just for testing and sometimes the car's audio would lower the volume of both the music and Siri's voice. So I couldn't rely on audio cues, I had to just look at my screen.

- One thing I love with the car GPS is that directions can be visualized on the center screen behind the steering wheel. I wish Apple Carplay could transmit it's directions there.

- For the car GPS, I switched the color of the icon representing the Niro to red (since that is the car's color). I'm surprised KIA didn't put the color of all their cars in the settings.