Driving over mountains vs City/Highway miles

I have often heard about the difference between driving in the city vs on highways and how they effect both gas mileage and the wear and tear on the car. I was driving to Burlington,VT from Portland, ME and back this week for a college interview and driving over the White Mountains seemed much different then either normal city or highway driving. Driving over the mountains does seem like it would be harder on the car, but by how much?

It’s definitely harder on the brakes, particularly the steeper the slope gets. It’s also harder on transmissions. Climbing steep slopes will also negatively impact gas mileage but I’m unsure if it gets completely “made up” when coasting down the slope on the other side.

I think it also depends on how much power the car has. My 4-cylinder SUV definitely struggles going up into the mountains, and mileage suffers greatly. I imagine a car with more HP would not find going uphill as hard, and may be easier on the mileage.

My new (to me) car can display either the instantaneous or average gas consumption. Driving uphill, the instantaneous mileage is downright scary. Coming downhill, you just wish you got that mileage all the time!

Today it was something like 9 MPG uphill, 67 MPG downhill, 22.8 average. Took my foot off the gas heading down the off ramp, and hit 200 MPG!

The biggest thing with highway versus city miles is that it takes a whole lot less time and fewer engine revolutions to rack up a given number of miles on the highway than in the city. It’s not that the city miles are “harder” on the car necessarily, it’s just that a car with a certain number of miles racked up in city driving has seen a lot more use than a car that’s done the same number of miles on the highway. Particularly since for most privately-owned cars (as opposed to taxis and such) city driving means shorter trips and more cold starts.

So, in that sense, so long as you’re still driving a long distance and going more-or-less at highway speeds, hilly highway miles should be pretty comparable to flat highway miles.