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156 � Transportation Statistics Annual Report 1996
BOX 7-3 (CONT’D): DREDGING OF SEDIMENTS IN PORTS AND HARBORS
Disposal in most freshwater areas and wetlands, estuaries, and coastal waters is regulated under the CWA.
Regulations setting quantitative sediment quality criteria have been debated for a decade and were finally proposed
in 1994.
Recognizing a need for improvements in the dredging review process, Secretary of Transportation Federico
Peña convened an Interagency Working Group on the Dredging Process in October 1993. 2 The Group’s Action
Plan for Improvement, submitted in December 1994, resulted in the establishment of an interagency National
Dredging Team and regional teams. The teams are helping to implement the action plan’s comprehensive recommendations.
The aim is to establish a more timely, efficient, and predictable dredging process.
2 U.S. Department of Transportation, Maritime Administration, Report to the Secretary of Transportation, The Dredging Process in the United States:
An Action Plan for Improvement (Washington, DC: December 1994).
� Highway Vehicle Scrappage
Dismantlers have long collected junk cars and
spare parts for resale, reconditioning, or recycling.
With the introduction of shredding in the
1960s, it has became more cost-effective to recycle
vehicles. By 1995, 94 percent of retired
vehicles were recycled, and 90 percent were
scrapped at shredders. (Curlee et al 1995; AAMA
1995, 55; Holt 1993)
According to Oak Ridge National Laboratory,
approximately 12.8 million tons of material were
generated from retired automobiles from June
1993 to June 1994. About 73 percent of this material
(9.4 million tons) was recycled. The remaining
3.5 million tons was placed in landfills.
The increase in highway vehicle recycling
over the last few decades has reduced the volume
of waste that would otherwise be placed in
landfills. Recent trends in the composition of
passenger vehicles, however, have begun to
make current recycling practices less viable economically,
thereby forcing vehicle manufacturers,
recyclers, and other organizations to find
new technologies and procedures for recycling
highway vehicles.
To improve fuel efficiency, manufacturers
reduced the weight of vehicles. Since 1976, the
weight of the typical family vehicle decreased
from 3,761 pounds to 3,169 pounds, an average
decrease of 592 pounds (see table 7-8). Much of
this reduction came through less use of steel,
TABLE 7-8: COMPOSITION OF A TYPICAL PASSENGER VEHICLE, 1976–94 (POUNDS OF MATERIAL)
Year Ferrous Aluminum Other nonferrous Thermoplastics Thermosets Other materials Total
1976 2,785.0 85.5 101.0 87.6 74.9 626.5 3,760.5
1980 2,423.5 130.0 71.0 97.3 97.7 543.5 3,363.0
1985 2,269.0 138.0 62.0 128.3 83.2 506.5 3,187.0
1990 1,985.0 158.5 65.0 128.3 93.7 465.0 2,895.5
1994 2,145.0 182.0 58.0 152.4 92.6 539.0 3,169.0
SOURCE: Ward's Automotive, annual editions, 1976–1994.