Google Maps should tell me where to get gas
(And, yes, I'm aware that the answer is "at a gas station." Thanks.)
Our vehicle has a trip computer that tells us how many more kilometres we can go on our tank of gas. It's very handy. And Google Maps can tell me how many more kilometres it is until the next town. Of course, that's helpful, too.
Linking those together in advance of hitting the road would be great. I'm thinking Google's smart enough to figure out that if I input the kind of car I'm driving and the speed of the highway (and I'd bet that Google already knows highway speeds), it can calculate my approximate gas mileage and compare that against my Google Maps route and tell me the most ideal place(s) to fill up with gas along that route to ensure the smoothest possible ride to our final destination without running out of gas.
For instance, if I'm driving from Edmonton to Seattle, and I enter that route into Google Maps and then select "find me gas" (or whatever we would call this option), it would ask for my vehicle make/model (again, something I would assume we could pre-program into the app), and then spit out something that would say, "You will want to get gas in Hinton, AB, and then again in Town Here, BC, and finally in This Place In Washington State."
And, voila! I now know I only need to make three gas stop on the trip and I'll be fine.
This idea is totally free for Google or Apple to steal for their mapping applications.