Thread: hwy speeds
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Old 08-08-2008, 01:51 PM   #14 (permalink)
aerohead
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speed/mpg

Quote:
Originally Posted by Binger View Post
I did a search but did not find what I wanted.

There is a long, flat state hwy that I will soon be driving on a daily basis. (approx 30 miles one way) The speed limit is 65 but I always go 55...there are signs that say that the minimum speed limit is 45mph. My commute will be during off hours when I usualy see one car if any.

My question is this...I know that driving 55 vs 65 saves alot... but will driving the minimum 45 make that much of a difference on this long of a commute?
Hi Binger! Once I drove my CRX from Lubbock,Texas,to the Dallas,TX area at a constant 45-mph.The trip was about 310 miles,one-way for the route I chose.The car returned 12mpg better mileage than at 55 mph(64 vs 52 mpg)I have 345,000 miles of data on the car and am confident with these numbers.The other motorists were pretty pissed at me,even though I moved to the shoulder far in advance of them( highly illegal in Texas!).I also drove the T-100 from Lindsay,TX to Electra,TX,roundtrip at 45 mph.The truck pulled 39-mpg.I've never tested the truck at 55 mph,however from its "map",which shows a very linear relationship between mpg and speed,it appears that the T-100 would get 35-mpg at 55 mph.That's all I have.I would caution you to presume nothing about your particular car.The reason I mention that is because my Dodge truck gets better mpg at 65mph,than it does at 55.Every car has it's own "sweet-spot."
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