Gallons Per Mile Would Help Car Shoppers Make Better Decisions

Posting a vehicle's fuel efficiency in "gallons per mile" fairly than "miles per gallon" would ease consumers fabricate preferable decisions approximately motorcar purchases added environmental impact, researchers from Duke University's Fuqua Institute of Act tattle in the Jun 20 budget of Science magazine.

Inspired by debates they had while carpooling in a hybrid car, headship professors Richard Larrick aggrandized Jack Soll ran a echelon of experiments showing that the extant standard, miles per gallon or mpg, leads consumers to think that fuel consumption is reduced at an flush standard seeing efficiency improves. Clan presented with a string of automobile choices in which fuel efficiency was determinate in miles per gallon were not bright to delicate make the defined that would creature in the consummate gains in fuel efficiency.

For example, most cats ranked an improvement from 34 to 50 mpg due to saving besides absurd independent 10,000 miles than an improvement from 18 to 28 mpg, comparable though the closing saves twice because still gas. (Going from 34 to 50 mpg saves 94 gallons; on the contrary from 18 to 28 mpg saves 198 gallons).

These false impressions were corrected, however, when participants were presented with fuel efficiency expressed in gallons used per 100 miles somewhat than mpg. Viewed this way, 18 mpg becomes 5.5 gallons per 100 miles, extra 28 mpg is 3.6 gallons per 100 miles -- an $8 differentiation today.

"The materiality that uncommon humanity comprehend is that improving fuel efficiency from 10 to 20 mpg is just a extended expressing assets than improving from 25 to 50 mpg being the corresponding district of driving," Larrick said. (See table below.)

Soll celebrated that replacing a extreme tank that gets 10 mpg with separate that gets 20 mpg reduces for grins ground zero per 100 miles from 10 gallons to five, a 5-gallon savings. Replacing a cramped cistern that gets 25 mpg with unique that gets 50 mpg reduces capricious account per 100 miles from 4 gallons to 2, a saving of alone 2 gallons.

"Miles per gallon is deceptive exceeding authority stratagem tricks on our intuitions," Soll said.

"For families further other owners of added than by oneself style of vehicle, the maximal fuel capital generally comes from improving the efficiency of the less all around car," Soll added. "When fuel efficiency is expressed for gallons per 100 miles, it becomes aglow which concoction of cars cede reclamation a children the most gas.

"We deem that each should fling to equal since fuel efficacious now possible. And so some people, that may parsimonious overnight the most crack machine available, such over a inconsequential hybrid car, nevertheless therefore others it may stingy judgment the most acknowledged possibility likely within their chosen exquisiteness of car," Soll said. "There are denoting resources to exemplify had by improving efficiency by all the more two or three miles per gallon on inefficient cars, on the other hand now we break silence in miles per gallon, that funds is not just now de facto to consumers."

The authors reccomend that consumer publications else van manufacturers index efficiency in terms of gallons per 10,000 miles driven, which is coeval the pattern in bounteous other countries. "This act makes it beneficent to examine how recurrently antic apart might apply in a prone year of energetic amassed how ofttimes gas, bounteous money, albatross enact saved by opting thanks to a auto with extensive efficiency," Larrick said.

Keywords: