table of contents - Research and Innovative Technology ...

Million short tons
120
��
��
��
�� 100
80
60
40
20
0
ON-ROAD VEHICLE EMISSIONS
��
Nitrogen oxides
�� �Volatile organic
compounds
Carbon monoxide
vmt
��
��
��
1970 1974 1978 1982 1986 1990 1994
SOURCE: See chapter 7, figure 7-1; and U.S. Department
of Transportation, Federal Highway Administration.
unpredictable timing of major tanker spills.
Water pollution also arises when oil, fuel, and
other chemicals leak from vehicles and run off
highways into bodies of water. Improper disposal
by vehicle owners who change their oil at
home is a pervasive, but unreported problem.
Millions of people who live or work near major
highways, airports, and railyards are exposed to
annoying levels of transportation noise. Transportation
noise rarely leads to hearing impairment,
but can lead to sleep loss and related health
problems. Policy measures are primarily aimed at
reducing noise at the source and shielding or
removing the receptor from the source. The localized
nature of noise makes it hard to characterize
its impacts at a national level.
Transportation vehicles and infrastructure
are major sources of solid waste. Recycling and
reuse of highway pavement is extensive, and
over 90 percent of retired cars are partly recycled.
Over the past two decades, cars have
become much lighter as manufacturers increas-
3
2
1
0
Highway vehicle-miles traveled–vmt (trillion)
ingly replace steel and other metals that are
more cost-effective to recycle with plastic and
composite materials that are less so. These
materials are often shredded and delivered to
landfills. As the materials used in cars continue
to change, new challenges are created for recycling
and reuse. Recovery for obsolete components
or parts of cars vary. Well over 90 percent
of obsolete car batteries are recycled; for tires,
however, the proportion was probably in the
range of 20 percent in 1990, although data are
limited.
The direct and indirect effects of transportation
on biodiversity and wildlife habitat are
poorly understood at the aggregate national level.
This is an area for research that will become
more important as land for wildlife habitats
becomes more scarce. The interrelationships
between transportation and land use, and their
implications for the geography of development,
are also important. Transportation improvements
often lead to urban sprawl, which increases
the amount of developed land and also the
demand for transportation.
Transportation and Air Quality:
A Metropolitan Perspective
Most travel, particularly by automobile, is
completed within metropolitan areas. Despite
the improvement in national air quality trends,
the Environmental Protection Agency (EPA)
currently lists 182 metropolitan areas as nonattainment
for at least one of the six criteria air
pollutants.
While urban highway travel has doubled in
less than 20 years, advances in automotive technology
have reduced pollutant emissions in metropolitan
areas and improved air quality. BTS
analysis of data collected by EPA for 13 major
metropolitan statistical areas shows decreases
between 1985 and 1994 in all criteria pollutant
emissions, with the exception of two areas
showing NOx increases. For instance, Los
xxiii