# What ever happened to the Energy Department's 100 MPG(e) production car? **URL:** \ **Category:** Factual Questions\ **Created:** [July 30, 2015, 8:34pm UTC](https://boards.straightdope.com/t/what-ever-happened-to-the-energy-departments-100-mpg-e-production-car/726606 "2015-07-30T20:34:40Z")\ **Posts on this page:** 2\ **Page:** 2
**Author:** ![Absolute](https://avatars.discourse-cdn.com/v4/letter/a/b2d939/32.png) [@Absolute](https://boards.straightdope.com/u/Absolute)\ **Post date:** [August 4, 2015, 4:07pm UTC](https://boards.straightdope.com/t/what-ever-happened-to-the-energy-departments-100-mpg-e-production-car/726606/21 "2015-08-04T16:07:06Z")
> [@Hari\_Seldon](#): > > Thought experiment. Which is more effective in reducing carbon emissions, raising gas mileage from 20 to 35 mpg or raising it from 35 to 100? > > The first reduces usage by 2.14 gallons/100 miles, while the second by only 1.86. This is why the European usage of liters/100km is a more useful way to measure fuel economy. Well, there’s nothing special about liters or kilometers that makes it more useful. The US would be better off using gallons / 100 miles. ---
**Author:** ![Hari\_Seldon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hari_seldon/32/5173_2.png) [@Hari\_Seldon](https://boards.straightdope.com/u/Hari_Seldon)\ **Post date:** [August 5, 2015, 12:52am UTC](https://boards.straightdope.com/t/what-ever-happened-to-the-energy-departments-100-mpg-e-production-car/726606/22 "2015-08-05T00:52:57Z")
> [@Absolute](#): > > Well, there’s nothing special about liters or kilometers that makes it more useful. The US would be better off using gallons / 100 miles. Of course. I thought that was implicit in what I actually posted. But if they ever go metric… [Previous page](https://boards.straightdope.com/t/what-ever-happened-to-the-energy-departments-100-mpg-e-production-car/726606.md?page=1)