The current amount of fuel consumption is essential to a discussion on natural resource consumption. For example, data suggest that the world’s oil supply is in both physical and political risk. The world’s conventional oil peak is estimated to occur between 2007 and 2012 and then production is anticipated to decline at roughly 3% per year; yet this date estimate is based on nominal knowledge of Middle Eastern reserves (Bentley, 2002). It is quite conceivable that the world has been in a state of peak oil in recent years or decades.
When considering fuel consumption specifically in the United States, the need for transportation sustainability becomes apparent. Studies indicate that 55% of the oil currently consumed in the U.S. is imported, and by 2025 this figure is expected to reach 68%, according to the Office of Energy Efficiency and Renewable Energy in the U.S. Department of Energy (2004). Two-thirds of the 20 million barrels of oil used each day in the United States are used for transportation.
Increased consumption of oil brings increased emissions from vehicles. According to the Transportation Research Board (1997), motor vehicles release approximately one pound of carbon dioxide per mile traveled. The Energy Information Administration (2005) estimates that carbon dioxide emissions for the transportation branch account for 33 percent of the United States’ total energy-related carbon dioxide emissions. This makes transportation the leading contributor to end-use total carbon dioxide emissions in the United States.
Figure 4 shows that in 2000 most (71%) of the transportation-related greenhouse gas emissions were from cars and trucks; buses and rail accounted for only 3% of these emissions (Pew Center, 2000). Furthermore, 98 percent of these transportation emissions stem from petroleum product consumption; the largest consumption group for petroleum, at 60 percent, is motor gasoline (Energy Information Administration, 2005).
Figure 4. Greenhouse gas emissions by transportation mode (Pew Center, 2000).
In the United States, when this gasoline is taxed, the funds incurred are redirected to surface transportation programs as dictated by the Federal Highway Trust Fund; this Fund splits the funds across two accounts: highway and mass transit (Metschies, 2004). Essentially, highway users are taxed to pay for highway projects. Fuel tax rates approach 10 cents per Litre in the United States; half of this amount is dispatched to the federal government and half is added to state-specific road and highway financing (Metschies, 2004). Only 2 cents per Litre, or one fifth of the total amount incurred, are diverted towards solutions for urban congestion problems.
The emissions from gasoline contribute to air pollution and related effects, such as global warming, ozone depletion, and respiratory health problems. For example, Santiago in Chile and Los Angeles in California both experience smog that persists for extended periods and with Chile adding 7% more vehicles on roads annually, the air pollution problems will not disappear (Brown, 1998). Additionally, students in schools close to major highways have elevated occurrences of respiratory distress; data show that people living within 300 meters of major highways are more likely to have asthma, leukemia, and cardiovascular disease (Bullard, 2005). Congestion on roadways also brings an increase in accidents, noise, and sprawl. Yet even before congestion occurs, roadway construction results in regional environmental effects. These include erosion, degraded stormwater quality, and increased chemicals, salts, noise, and hazardous materials; as traffic increases, vehicle noise may impact adjacent animal communities in a region (NCHRP, 2002).
Another impact from building a roadway may be a change in regional landscape patterns that results in the fragmentation of surrounding wildlife habitats (NCHRP, 2002). Fragmentation’s impact is twofold; it includes diminished species biodiversity due to reductions in available habitat and additional disturbances from the increased access for hunting, timber harvesting, and development that road building provides (World Resources Institute, 2000).
Уважаемый посетитель!
Чтобы распечатать файл, скачайте его (в формате Word).
Ссылка на скачивание - внизу страницы.