

| Subject: | Re: better gas mileage |
| From: | John Bange |
| Date: | Fri, 16 May 2008 11:31:55 -0700 |
> "The Union of Concerned Scientists tells us that dropping from 70 to 60 mph > improves fuel efficiency by an average of 17.2 percent. *Dropping from 75 to > 55 improves fuel efficiency by 30.6 percent*!(3) > > And the time you save by going easy on the accelerator may not add up to as > much as you thought. On a 300-mile trip, driving 65 instead of 70 mph would > cost you only 20 minutes -- but save money and spew less carbon." I'm always amused by how they use BIG speed variations to demonstrate fuel economy, but suddenly switch to a SMALL speed variation to demonstrate change in travel time. Of COURSE 70 to 65 only loses 20 minutes--- it's not a significant drop. Dropping from 70 to 60 adds 45 minutes, turning a 4.25 hour trip into 5 hours. 75 to 55 adds a whopping 1.5 hours, turning a 4 hour trip into 5.5 hours. How about a drive from LA to Yellowstone? 14 yours at 75 vs 19 hours at 55. That's They try to paint it like there's nothing to lose and everything to gain by slowing down, but it's simply not true. Short trips, like my 10 mile commute to work, you gain a pointless THREE MINUTES at 75 vs 55--- THAT'S where people need to slow down. For long trips you really need to calculate your time budget vs your fuel budget to come up with an appropriate speed. If it's purely about conservation, then a brick like the Vanagon probably hits its optimum at 40-45mph! Can you imagine a 26 hour trip to Yellowstone at 40mph? And really, a 30% gain from 75 to 55? I've tried that with every vehicle I own, and whichever vehicle these Concerned Scientists were testing, it wasn't a 94 Honda Civic or a 90 Vanagon! Personally, I LIKE driving slow in my Vanagon. I seldom break 65 on long trips and my wife tries to keep it below 70 -- John Bange '90 Vanagon - "Geldsauger" '90 Vanagon GL - "Wiesel"
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