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From: seifert@ihuxl.UUCP (D.A. Seifert)
Newsgroups: net.auto
Subject: Re: RE: farce?
Message-ID: <1195@ihuxl.UUCP>
Date: Tue, 26-Jun-84 09:01:14 EDT
Article-I.D.: ihuxl.1195
Posted: Tue Jun 26 09:01:14 1984
Date-Received: Thu, 28-Jun-84 02:43:30 EDT
References: <2120@ihnss.UUCP>
Organization: AT&T Bell Labs, Naperville, IL
Lines: 64

> "But my car gets better mileage at 70 than 55":  As has been pointed
> 	out before, there is definitely more energy spent per mile in
> 	overcoming friction and drag at the higher speed, since both
> 	have components that grow faster than linearly with the
> 	speed of the car.  Poor tuning or gear ratio selection can
> 	result in anomolous behavior, but I really doubt the claims
> 	that with a normal car and comparable driving you do better.
> 	Right after the 55mph limit was imposed, there was a real
> 	problem with trucks that had been designed with their top
> 	gear appropriate for travel at 70.

There is also the problem that some cars cannot cruise at 55 in top
gear, either.  This forces then to run in a lower gear and use more gas.

How come your friendly neighborhood DC-10 doesn't have to go 55?
I bet it would get better milage at a slower speed too.

> Having seen driving behavior in both the pre and post 55mph era
> (guess that dates me), and behavior in other countries, I have
> another theory about poor mileage and accidents as a result of a
> speed limit decrease:
> 
> 	My guess is that each driver/car has a natural "terminal"
> 	velocity, one at which the pressure of foot on gas pedal is
> 	comfortable and the road noise and the scenery flying past
> 	is not too uncomfortable.  On the autobahns and before the
> 	days of 55mph limits, the natural limit for most people was
> 	at or below the legal limit, thus people drove at a
> 	comfortable pace, driving alertly and at a consistent speed.
> 	
> 	55 mph on a road designed for travel at 70 seems unnaturally
> 	slow to most drivers.  This problem is made worse by the
> 	increasing use of streamlining and airconditioning, which
> 	decrease your sense of speed.  Thus people are constantly in
> 	conflict, relaxing their vigilance and letting the
> 	spedometer creep towards 75, then realizing that they are
> 	suddenly passing a lot of other cars and slacking off (or
> 	even slamming on the brakes) before they get caught.  I have
> 	seen many people who drove with gas and brakes in
> 	alternation at 55.  This kind of oscillation probably hurts
> 	mileage and causes accidents.  It certainly increases the
> 	perception of inefficiency and danger.  Maybe we ought to be
> 	designing cars that make it more apparent how fast you are
> 	really going!

Going 55 on a road good for 70 (or 90, or whatever) not only
*seems* too slow, it IS too slow.  Safe driving demands proper
concentration. put-puting along at 55 on a typical interstate
is very dangerous.

If you're looking for wind-in-your-face, convertibles are coming
back, and I think you can still fold down the windshield on a
Jeep. (though I'm not sure if it's legal to on the road)  There's
always motorcycles.

I'll stick with a 'streamlined' car with air. Gets better mileage that
way. (air uses less gas than the aero loss from open windows or roof)
Safer too, there's a *reason* Jeeps come with roll-bars.
-- 
	_____
       /_____\		Hey, Woodstock, have you seen my sunscreen?
      /_______\	
	|___|			    Snoopy
    ____|___|_____	       ihnp4!ihuxl!seifert