The pm econo caper
 

THE PM ECONO CAPER,Coast to coast for $100? They told us we were crazy.
Popular Mechanics Magazine,August 1991.
The above article is something I've referred to when looking at the T-100/Viking road-test data.
They drove a Geo Metro LSi from San Francisco to New York City,2993-miles,I-80 all the way,at 63-66 mph,never exceeding 75-mph.
They averaged 53.2 mpg for the trip.
The worst tank was 50.0 mpg,climbing from sea level,up over Donner Summit,7,239',down to Fernley,Nevada,at 4,160'.
Their second worst tank was between Fernley and Battle Mountain,Nevada,4,511',at 50.8 mpg,dropping at Lovelock,then climbing to Golconda Summit before dropping into Battle Mountain.
From there on,they never saw below 51 mpg.
Their best tank was between Cheyenne,Wyoming,6,062' and Goehner,Nebraska,1,542', at 56.2 mpg.
Their worst tank was 6.4% lower than the trip average.
Their best tank was 5.63% better than the trip average.
Between best and worst,mpgs demonstrated a 12.4% spread at constant weight,indicating mpg variability due to weather and grades.
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The data scatter emphasizes the care we must take when accounting for variables when attempting to discern mpg changes attributable to drag reduction from mods.:p

Google found a link to the full article:
PM Econo Caper