I’ve known forever that city mileage for cars is worse than highway mileage, but I never knew why. But it’s a bit like riding a bike.
When you ride a bike, you have to put in a lot of work at the beginning, getting up to speed. And after that, you can mostly coast. Assuming you’re on flat ground, you have to pedal a bit because friction is slowing you down, but it’s nowhere near how hard you had to work getting up to speed.
And then you stop at a red light, and you throw away all the energy you had, so that when the light turns green, you have to put in another burst of work getting up to speed. And, of course, in the city you’re stopping like this all the time. Every few blocks, you throw away all your accumulated energy, and have to start over. This applies to cars the same way as to bikes, except that on your bike, you immediately sense this in your legs, not at the end of the week when the tank is empty.
So it’s not that highways somehow enhance your mileage. Rather, it’s cities that make for wasteful driving. It’s a bit embarrassing that it took me this long to figure it out, but better late than never.