The Influence of Weight

1
The Influence of Weight

• Freight-ton miles per heavy-duty diesel truck
• Average model weight of light-duty gas vehicles
  and trucks
• By Natalie Zaczek

2
Freight-Ton Miles

• Amount of freight being transported has
  increased steadily every year
• There is an increasing demand for freight
  transportation
• The plateau in total freight, but increase in
  freight-miles means that less freight per haul.
  (There is a steady increase of length of haul, so
  there is not a decrease in the distance freight
  travels)

3
Freight/Person
Freight/Vehicle

• There was a rapid decrease until 1980 (when the
  freight/person was flat)
• Peak mid-1990s
• Decreases from mid-1990s-2001

• There was a dramatic increase from 1980-mid1990s
• Peak in mid-1990s
• Decreases from mid-1990s-2001

4
Light-Duty Gas Weight Trends for the Model Year

• 1975-1980 a rapid increase in fuel economy and a
  rapid decline in weight
• 1980-2002 a slight decrease in fuel economy and a
  large increase in weight

• -Vehicles and trucks weighed the same in 1975
• -Rapid decline in weight from 1975-1980
• -Weights constant from 1980-1990s
• -Weight increase from the 1990s to current

5
Weight Increase and Decrease

• Influence on weight decrease (1975-late 1980s)
• CAFÉ
• Govt. policy to increase fuel efficiency in 1975
• FMVSS
• no safety changes from 1974 -1986
• Influence on weight increase (late 1980s 2004)
• FMVSS
• Increase in weight of safety equipment
• Technology
• Used to increase weight and acceleration

6
FMVSSFederal Motor Vehicle Safety Standards

• Federal Motor Vehicle Safety Standards (FMVSS)
• Reverse engineering to find out how much weight
  was going towards safety
• Safety includes avoiding crashes, fires, and
  other hazards, and regulating crashes.
• Weight in passenger cars changed little from
  1974-1986 because no new FMVSS changes
• Many safety technologies in cars later than in
  light trucks
• There is an increase in safety weight from
  1990-2000 and there is also an increase in the
  average weight per model year during the same time

7
Technology Improvement Weight Gain

• Technology goes to increase weight and
  acceleration, not fuel economy
• Weight increased 21
• Horsepower increased 79

8
Ton-mpg

• Ton-MPG is the miles per gallon times the weight
  in tons (fuel economy)
• Tells ability to move weight
• Also tells about the power train and drive-line
  efficiency

9
Why did the ton-mpg increase while the weight
increased?

• There are many factors that affect fuel economy
• Weight
• Technology

If the 2000 model year light vehicle had the same
performance and weight as the 1981 model year,
there would have been a 25 higher fuel
efficiency.
10
Conclusions on Weight

• Weight affects fuel economy
• More freight is being circulated via trucks in
  2002 compared to 1975. This means that more
  weight is being transported.
• Weight declined, but then start to increase again
  all while the fuel economy also increased. This
  indicates that there are other factors involved
  in the fuel efficiency such as technology.
• Once technology has reached a plateau, changes in
  weight may affect changes in fuel economy more.