Measuring Efficiency

[superchow]

I have been looking at different ways to measure efficiency compared to MPGs. The goal overall to reduce emissions and save the planet while still getting around is noble. However, IMHO most people consider their wallets before considering the environment.

I have also been tracking MPGs with premium fuel vs regular fuel for a long time. Yes, with my car and with my real-world situations I have seen about 10% more MPGs with premium over regular. However, as my lovely wife has pointed out, does that increase in efficiency offset the additional cost of the fuel? When fuel was over $3.50/gal the additional 20-30 cents/gallon didn't make much difference, but now that we are in the $2.50 range it's more noticeable.

So - we started to track cost per mile ($/mi) rather than miles per gallon (MPG). Because really, isn't that what people want? Low cost per mile? No matter how they get it? Regular, premium, diesel, electric, etc. It all costs money, and that is the unifying factor for us all.

Our Ford is now at around $0.12/mile and the Honda at $0.08/mi. That informs me better on how to justify driving a 22 MPG "monster" compared to my "frugal" 35+mpg Civic. It let's me weigh the additonal cost of $0.04/mi for the additional comfort and practicality, especially now that we have to do diaper changes and breast feedings while on the road.

My question is this: How do you measure efficiency/consumption/expense/etc. when it comes to transportation? Is MPG good enough? Thoughts? Comments?

[NoD~]

I put together a spreadsheet for my Neon at one point. Column of items, such as tires, fluid, filters, battery, suspension, belts, plugs, bulbs, etc. Next column was cost for each one of these, then a column for replacement miles. Finally, I divided the miles by the cost and added it all together. It came out to be $0.08688/mile (at 46MPG, $2.00 a gallon). This does not include insurance and registration. Updated to 2.50 a gallon, it's about $0.09805/mile.

Just did my Insight... sadly, it's not as low as I'd hoped. $0.09598/mile. Though, this is considering IMA replacement every 100,000 miles at $2,100 a pop. Don't include that and you are looking at $0.07498/mile.

[oil pan 4]

Yeah same here, the finicky VW 1.8L turbo gets much better fuel mileage with premium usually around +7mpg.

[Gasoline Fumes]

I mostly pay attention to MPG, but my cost per mile of 3¢ isn't bad.

[oldtamiyaphile]

You won't really know your cost per mile until your car dies of old age or you sell it on. Just sayin'

[freebeard]

Rather than focusing on other consumables, I prefer to consider miles per gallon of anti-freeze, which is poisonous to puppies and kittens. My VW Beetle, and it's eventual electric replacement will remain at infinity divided by zero.

Considering electricity, I pay 5¢ per kilowatt-hour. If I were to drive across the bridge into the next burg over, the cost of a recharge would double. If I were to venture outside the PNW, it would triple. And more coal miners would die.

[NoD~]

5c per KW/h?! Where do you live?!

Annual Electricity Price Comparison by State

Low fluid count is easily one of my favorite reasons to go electric (...which I have yet to do. I do have a 70's VW beetle that's been a contender, though. Just need the green to fund the green. BTW the beetle is green.)

[redpoint5]

I use the vehicle cost of ownership calculator spreadsheet that is linked in my signature to estimate total cost of ownership and cost per mile. Many assumptions have to be made to get an approximate cost, but it is useful when comparing vehicles since you can hold certain variables constant and see how different fuel or electricity consumption rates affect the cost.

[freebeard]

NoD~ -- I checked, it's 5.27¢. I don't want to give up too much more than 'nortwest of normal' but that next burg over is Bluegene, OR.

Possibly Elm green? My last car was same make year and model in Elm green. The EV conversion I'm fitting to a '58 Baja Bug may get transplanted into the Superbeetle at some point.