Duke professors challenge term "miles per gallon"

The News & Observer (NC) ^ | June 19, 2008 | Eric Ferreri

[Publius6961]

I trump all other suggestions on this thread.

I got a blank stare when I told an "average" detroit iron doofus that at cruising speed on the the freeway, not speeding, he was burning 25c a minute, and at 80 mph, it was probably 50c...

Easiest measure to understand.

The average driver would respond that, if he drives 200mph, he would burn just 15 minute's worth on a 50 mile trip...

[sionnsar]

Hmmm, so two college professors want to turn a well-known number upside down.

The Europeans (at least the Germans) use that system. I see nothing wrong with it -- except that we are accustomed to our system and I see no particular advantage in changing, except to two professors who seem to want some attention.

[supercat]

I only have cash on hand for 5 gallons. How far will that get me?

That's one case where M/G is better than G/100M. How much gas will it take me to drive 300 miles to visit my aunt?

If the car takes 3.1G/100M, then it would be 9.3 gallons.

\What is the relative cost of driving to a store 25 miles away, versus the one 10 miles away?

An extra 15 miles. At 3.1G/100M, ten miles would be about 0.31G. Since 15 miles is half again that, about 0.46G.

The situations in which I have to deal with multiples of 1000 miles are rare.

The question is whether it's more convenient to multiply or divide. Generally, multiplication is easier, though a lot depends upon the exact numbers involved.

[supercat]

In the second place, nobody comparison shopping cars is looking at vehicles with 18-28 mpg range and vehicles with 36-50 mpg range.

The misses and I are looking to get vehicles. We need to have a vehicle that can haul some heavy cargo, but we'll both be driving about the same amount. We have a certain budget for both vehicles.

Improving the fuel efficiency for either vehicle will cost money. Given a choice between spending an extra $3500 on the SUV to improve it from 20 to 25mpg, or between spending the same amount to improve the commuter car from 40 to 60mpg, which makes more sense?

Flip the units, and a change from 5 to 4 G/100M is easily seen to be larger than a change from 2.5 to 1.66G/100M.