How come we get better mileage on the highway than the city?

Question

I'm just curious, since I don't know why.

Answer 1

The answers already here are pretty good answers.

It mostly has to do with accelerating and decelerating. You have to stop for lights, stop signs, small dogs, children, bouncing balls, disoriented bums with squeegees, etc. Every time you do this, you have to bleed off speed by using your brakes. You bleed off your momentum, which you bought by burning fuel by wastefully converting it to heat in your brakes. After the bum has finished negligently wiping your windshield, you have to re-accelerate by burning more fuel.

Consider also this extreme example of gas mileage. When you're stopped, idling at the stop light, your mileage, at that point in time is effectively 0MPG. You are getting NO miles per gallon because you are burning fuel, but not moving. 0MPG tends to pull your overall average down, pretty severely.

Another factor is that freeways tend to be as smooth as we can make them, reducing tire friction, while surface roads tend to be course, bumpy, full of patches and chuckholes.

There are probably other minor causes, but that about covers the major ones.

Answer 2

It depends on how you drive on the highway. Generally speaking, optimal gas mileage is on the highway, going a steady 50 to 55mph, while keeping the rpms relatively steady.

An engine burns more fuel in the lower gears while it is trying to accelerate. Think about a wheelbarrow: It requires a significant amount of force to get it rolling, but once it's rolling you don't have to put as much effort into maintaining the movement. The stop and go traffic of city mileage puts more exertion on the engine.

Also, a car with high mileage due to highway travelling is more desireable than a car with high mileage due to city travelling.

Answer 3

Well city driving is one stop light or sign to the next and a lot of stop and go.
The highway you go say 60 and just go no stop and go.
Since that stop and go is what eats up the gas it is better and more fuel effective to drive on the highway.
This is also why car makers rate there cars milage as city and highway miles..

Answer 4

Well in the city your doing a lot of stoping and going and your in a lower gear on the highway your staying more a constant speed and your in the highest gear reduing your rpms and using less fuel but in the same note after you shift in the high gear the faster you after that will also use more fuel so if you car hifts in to high gear at 50 every thing about it would use more fuel

Answer 5

On the highway you maintain a more or less constant speed with a relatively light load.

In the city you are constantly accelerating/decelerating/stop/start/changing speeds...all of this increases load, and therefore increases fuel consumption..

Answer 6

In a city you stop and go traffic and your speeds vary. Highway is constant speed and (most of the time) not stop and go traffic. This saves gas.

***Use cruise control to save more gas

Answer 7

Because you are running in a higher gear. Physics says that mass in motion tends to stay in motion. So it takes less power to maintain a speed than it does to get up to speed. So since it takes less energy, we use less gas.

Answer 8

cause most hwy u travel without having to stop and go so much like in the city.

Answer 9

No stop and go.