Path: utzoo!utgpu!jarvis.csri.toronto.edu!me!ecf!hiraki
From: hiraki@ecf.toronto.edu (Lester Hiraki)
Newsgroups: ont.general
Subject: Re: Highway Driving Rules
Keywords: speed limits = wasted gas, wasted time
Message-ID: <852@mv03.ecf.toronto.edu>
Date: 6 May 89 02:12:52 GMT
Organization: Engineering Computing Facility, University of Toronto
Lines: 24

In article <1693@dciem.dciem.dnd.ca> tim@dretor.dciem.dnd.ca (Tim Pointing) writes:
>Alas, this argument falls down when you look at the math of the situation.
>The cars mileage (kilometreage?) goes up as you slow down from 70 to 55.
>Since the distance you are travelling has not changed, you will will
>actually use less gas running your car for longer.
>
>	distance / mileage(mpg) = gas_used
>	  CONST  /    INCR      =>  DECR
>

Yes, the math of the situation......
What everyone so far has failed to realize is that air resistance
increases as the *SQUARE* of the speed.  Travelling at 115km/h instead
of 90km/h takes approximately 25% more fuel.  In Olympic cycling,
a racer expends 90% of his/her energy just spreading the air in front.
The moral of the story is this:  at high speeds air resistance 
dominates over frictional rolling resistance.  I am not advocating
driving faster or slower.  Each will have to decide the value of their
time relative to the square of their speed.

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