Car and Driver: Mileage? No, it's Your Gallonage that Really Counts

There is another illusion. I see folks on PriusChat finding longer routes that yield better MPG, without noticing that they are consuming more gasoline. You do not really wish to maximize MPG (that is just easy for the car to measure) you actually wish to minimize gallons used. Which may be a shorter route that yields less MPG.

 

"My Prius gets twice the MPG than your car; I make up for that by driving twice as much."

JeffD

 

People actually do that? Are they daft?

 

Fortunately, for the next year or so of EPA fuel economy stickers, they will be including 'gallons per 100 miles' figures at least in small print.

I suppose most people don't think of the non-linear curve of 'gal / mile vs. MPG's. When you get down into the lower registers of fuel economy (i.e. under 20), the gallons start adding up fast. 15 MPG ...OUCH!

On flip side, curve flattens out on higher end. Not too much difference in gas used between 50 and 100 MPG. Only 4 gallons difference after 400 miles.

 

Canada has been posting the MPG in UK and L/100km for a while. I like the L/100km specifically on the prius because its bar graph shows you how well you conserve fuel for 0-2.5 where on the MPG prius the graph won't tell you if you did any better than 99.9mpg.

On the flip side when you are trying to convince people to pay out of pocket to buy a more fuel efficient vehicle it's hard to tell someone to buy the Prius at $27800cdn that gets 4.7l/100 (2.0gal/100miles) vs say a kia rio that gets 6.9l/100 (2.9gal/100miles) at $10,000 less. That's ten grand to save just over 2L (.9gal). When you look at it in MPG you see 50 vs 34 and suddenly your ten grand is getting you a difference of 16.

 

Yep, I also really like that we get L/100 km here in Canada.

I much prefer that unit because it actually gives you a mesure of your fuel consumption instead of a distance you can travel. Much more direct and useful, since we pretty much like to save fuel with our Prii.

 

To me it's 6 of one half dozen of the other. Different ways to represent the same thing, as math often allows.

 

... this sounds well and good, until I remember the level of average American math skills.

 

i agree with scoorb, plus, people who drive trucks that get 9mpg instead of 10 could care less. people who drive cars that get 50mpg care about every last bloody drop!

 

When I bought my Prius in January of 2004, in North Dakota, with temperatures down to 30 below at night and sometimes staying below zero (F.) in the daytime, and a three mile (ten minute) commute, I was getting the lowest mpg on Prius Chat, yet burning fewer gallons of gasoline than anyone else here. I was happy with that. I remarked at the time that the mpg game is counter-productive if you are taking longer routes in order to show larger mpg numbers.

 

how about personal gallons per lifetime?

 

How about a different spin on miles driven?

I retired a few years ago, and was conscious of wasted gas to the point that I was forgoing pleasure trips.

Having a Prius lets me drive 50% more, using 50% less than my old sedan; so it has enriched my life and saved gas at the same time.

But another word on whether drivers are trying to save gas or get a pretty number. If one is truly trying to save fuel, it helps to consider the usage of those around you. If you force a truck to slow down you are wasting fuel; if you fail to allow a car to turn, this holding up a line of cars coming towards you, you are wasting fuel.

 

There was a promotional drive of a new vehicle (Hyundai) over at CleanMPG: they drove the vehicle around the continental US (the contiguous states), to promote fuel efficiency.

 

I bought my Prius about three weeks ago and I've fallen into this thought trap. I'm wondering when my driving will taper off. Right now, I'm just enjoying the car so much that I'm looking for excuses to drive it.

One of my major reasons for getting the C was to reduce the amount of gas used. I have a Harley Nightster that was my only gas burning vehicle for the past three years. It gets in the high thirties in the city and 45 on the highway if I am easy on the throttle.

I live in a city with average to middling public transportation. It takes double or triple the amount of time for a cross-town trip using public transport vs driving. So having a car for me has opened up more possibilities of things to do.

To offset this, I bought a bicycle and made a rule that the car is for any trip over two miles and the bike is for short errands and random short hops.

Anyway, your comment was thought-provoking (and just plain provoking...LOL).

Thanks

 

Very good points. When I was new to my C, I was very gentle on the throttle from stoplights/signs. Then I thought about the spaces between the lights and the amount of cars that could fit into the space. It was pretty obvious that saving gas via light acceleration has a greater aggregate effect for those around me.

So I generally keep up with traffic using moderate acceleration and remain within 5-7 mph of the speed limit in the city and 7-10 mph on the highway.

On a mildly similar note, I'm constantly amazed at tailgaters. In my C, i generally cruise towards the right (slow or second to slow). with the cruise control on. In a clear field, other drivers climb right up on my bumper and linger there for several miles before going around me. I just don't understand the thought process behind that if there even is one...

 

^^ This is why I de-badged my C. I have had 0 tailgaters since.

 

Great series of posts with thought provoking ways of looking at mileage.

I didn't buy my Prius to save the world, I bought it because I'm a geek and I love technology and treasure efficiency. I calculated a 7 year break even point at $3.10 / gallon. That break even point will move closer if gas prices go up of course, but you can't save more than you would have spent on fuel. Let me say that again: You can't save more than you would have spent on fuel. You probably won't save more than half of it, moving from 25 MPG to 50 MPG for example. I didn't even do that well as I sold a perfectly good Corolla (only 122K miles on it) to buy my Prius C. You have to drive a lot before fuel becomes a significant portion of your total costs. If you have a 3 mile commute and you stay home on weekends, any extra you paid for your hybrid was pure toy money. Just be honest with yourself and get back to enjoying your toy. I now relax at red lights where my idling engine used to annoy me. I no longer hate applying the brakes quite as much as I did in a conventional car, as long as I can pull a decent regen. Either you get it or you don't. My wife doesn't, to her it's a nice but slightly under powered way to get from point A to point B. Nothing special. She cant tell 1080p from 720p either.

 

I've always had an issue with tailgaters before I bought my Prius. I do the speed limit and I don't speed. I refuse to. If someone wants to tailgate me, fine. If I end up slamming on the brakes the A-hole behind me is at fault and their insurance will have to pay. I'm not going to speed because some jerk wants to ride my butt. Most of the roads I drive on have 2 - 4 lanes in each direction. If they don't like my speed move to another lane! I'm not breaking a law because someone wants to feel like a bully in the road.