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
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)
Freight/Person Freight/Vehicle • There was a rapid decrease until 1980 (when the freight/person was flat) • Peak mid-1990s • Decreases from mid-1990’s-2001 • There was a dramatic increase from 1980-mid1990s • Peak in mid-1990’s • Decreases from mid-1990’s-2001
Light-Duty Gas Weight Trends for the Model Year -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 • 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
Weight Increase and Decrease • Influence on weight decrease(1975-late 1980’s) • CAFÉ • Govt. policy to increase fuel efficiency in 1975 • FMVSS • no safety changes from 1974 -1986 • Influence on weight increase(late 1980’s – 2004) • FMVSS • Increase in weight of safety equipment • Technology • Used to increase weight and acceleration
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
Technology Change = Weight Gain Technology goes to increase weight and acceleration, not fuel economy Weight increased 21% Horsepower increased 79%
Ton-Gallons per Mile • Ton-Gallons is the gallons per mile times the weight in tons (fuel economy) • Tells ability to move weight • Graph shows an initial sharp decrease, then a plateau from about 1980 to 2002
Why did the ton-gallons per mile plateau 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.
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.