There are a couple of things to consider when choosing a navigation route: Which one will be the fastest? Which one is the fewest miles? Google Maps can also show you which route will save the most gas.
Google Maps factors in things like road incline and traffic congestion to figure out which routes are the most fuel-efficient. It's not as simple as just choosing the route with the fewest miles. By default, Google Maps will prefer these eco-friendly routes if the estimated time to arrival (ETA) is about the same as the fastest route. You can manually choose these routes yourself, too.
At the time of writing in October 2021, fuel-efficient routes are only available through the Google Maps mobile apps on iPhone, iPad, and Android. It's not available on the desktop.
To get started, open Google Maps on your iPhone, iPad, or Android device. Search for the location you'd like to visit and tap "Directions."
You will now see a few possible routes you can take. If Google Maps has already selected the most fuel-efficient route, you'll see a leaf icon on the blue highlighted route.
If the fuel-efficient route isn't already selected, simply tap it to make it your route.
With the desired route selected, tap "Start" to begin turn-by-turn navigation. You're on your way!
It's unfortunate that Google isn't making this feature available in the desktop version of Google Maps. Sure, it's a navigation feature, which means you're most likely to be using it on your phone in a car. But it would be nice to be able to use the desktop for planning, and it is possible to send directions from the desktop to your phone.
Regardless, whether you're trying to be environmentally friendly or you just want to save some money on your next road trip, this is a handle little tip to know. Google Maps has a lot of tools to make road trips better.