I believe the reverse is true.  I believe the SI Brochure has embraced the idea 
that certain commercial situations and everyday life are so committed to some 
special units that it is senseless to attempt change.  These include the liter, 
metric ton, hectare, minute, hour, and day (they did kiss the stere goodbye).
 
We should not change for change's sake, we should change to solve problems. So, 
before we can discuss change, can we define the "problem" of people using km/h 
in everyday life?  It seems like it is  . . . ., Well, what is it?  I don't 
know.
 
Engineers need to know they need pure base units for calculation, but they 
already know this.  In everyday life, few people do such calculations.  Mostly, 
they want an estimate of how long it will take to get somewhere.  While they 
could probably convert the kilometers to meters, they frankly don't want the 
answer in seconds (except possibly in a race).
 
Cars haven't been around the whole time, but in over 200 years, metric 
countries seem to have gravitated universally towards kilometers per hour for 
boats, trains, cars, planes, and no country sets m/s speed limits or marks 
speedometers thusly.  In countries not already metric, such a proposal would 
simply add to any existing "the metric system is inconvenient" sentiment.  I 
don't think it would be well-received in metric countries either.  Why rock the 
boat?

--- On Tue, 7/14/09, Pat Naughtin <[email protected]> wrote:


From: Pat Naughtin <[email protected]>
Subject: [USMA:45365] Speed in metres per second
To: "U.S. Metric Association" <[email protected]>
Date: Tuesday, July 14, 2009, 8:47 PM











I wonder if we will ever be ready to embrace the idea of using the SI unit, 
metres per second, for speed in everyday conversations.

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