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Path: utzoo!watmath!watnot!watmum!tjsmedley
From: tjsmedley@watmum.UUCP (Trevor J. Smedley)
Newsgroups: net.auto
Subject: Re: Obnoxious driver awards
Message-ID: <437@watmum.UUCP>
Date: Wed, 12-Mar-86 11:13:15 EST
Article-I.D.: watmum.437
Posted: Wed Mar 12 11:13:15 1986
Date-Received: Thu, 13-Mar-86 06:58:05 EST
References: <200@copper.UUCP> <224@gc49.UUCP> <478@codas.ATT.UUCP> <951@felix.UUCP>
Reply-To: tjsmedley@watmum.UUCP (Trevor J. Smedley)
Distribution: na
Organization: U of Waterloo, Ontario
Lines: 34
Summary: 

>> One car length for each "60" mph???  I defy anyone out there to stop
>> a cycle going 60 mph in one car length (of course unless you run into
>> the back of the car, that should stop you rather suddenly!)
>
>Actually, that works out pretty well, as long as you can brake equally
>or better then the guy in front of you 

And provided you can go from having you foot on the gas pedal going 60
mph to your foot on the brake pedal at full force in less than 1/6 of
a second. It takes about that amount of time to travel 1 car length
(estimated at 15 feet) doing 60 mph, so that's how long you have to
get your braking force up to the same force as he had when you started
to react (actually you have a little bit longer when you take into 
account that you may actually get your foot off the gas pedal within 
the 1/6 sec., so you start to slow down a little).

A better estimate for the time required for this would be about 2 sec.
and that's how far behind the car you should follow (longer for cars
which have superior braking power or for motorcycles). If you were
following one car length behind me doing 60, and for some reason I 
slammed on my brakes without warning, and perhaps my brake lights
didn't work, then you would almost undoubtedly be in my back seat
before you had time to get your foot poised over the brake.

Didn't anyone else learn the 2-second rule?

Trevor J. Smedley                    University of Waterloo

{decvax,allegra,ihnp4,utzoo}!watmum!tjsmedley

Disclaimer: I will be the first to admit that the 2-second rule is not
always appropriate, but it's a much better guideline than one car
length per 60 mph. BTW, someone here says that it should actually be
one car length per 10 mph. This makes a little more sense to me.