Why does a car get better mileage on the highway compared to the street?

Question

Driving at high speeds decreases mileage, but so does constant acceleration and braking.... so how does driving at higher speeds on the highway give you better mileage according to EPA mileage info?

Answer 1

I don't really know about all these but i do have the same curious as your. And i think that its must be something involves with the stopping when you driving in the city.

Answer 2

It takes less fuel to keep your car going at a constant velocity than it does to get it moving from a stop.  All the stop and go you do in city driving uses more fuel than a constant speed on the highway.  Idling and accelerating are the two biggest drains on fuel economy, and you do them often in city traffic.  By keeping the throttle relatively still and not flucuating  much on the highway, you are delivering a constant even fuel supply to the engine, instead of large amounts of fuel in bursts during stop and go traffic.  Now, just because you get better mileage on the highway does not mean the faster you go the better economy you get.  There is a point of diminishing returns where the vehicle's aerodynamics will start to bring down fuel economy.  But, driving at a constant speed is what gives you the fuel economy advantage over city driving.  Hope this helps.

Answer 3

Because you are not stepping on and off the gas. Use cruise control and you'll use even less gas on the highway

Answer 4

Numbers given are examples only........It could take a long version but i'll try to be brief...... Say it takes a 3000 lb car all of its 275 HP to accelrate and then you slow down and then accel. and the car can use  5 lb of gas per min to produce that, city driving you are accel almost always. with the highway driving it still takes 275 HP to accel but then you may only need 175 to maintain speed, less accelrator pedal and you may only be using 3 lbs fuel per min for 175 Hp