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S U S TA I N A B L E T R A N S P O RT: D E F I N I T I O N S A N D R E S P O N S E S 37 There have been several other proposals for the identifi- what sustainable transport is. Some of the definitions cation of indicators of sustainable transport, often in the are narrow, some are broad, and some seek to use indi- absence of a clear definition of what sustainable transport cators of the phenomenon, probably with the view of is. One of the leading efforts in this regard was outlined for moving toward measurement at some point. the National Science and Technology Council Transporta- tion R&D Committee by Heanue (1997). At the time the indicators under consideration included the following: NONSUSTAINABLE COMPONENTS OF TRANSPORT 1. Market penetration of alternatives to petroleum- It may make sense to identify some of the phenomena based fuels; that are generally accepted as leading the transport sys- 2. Transport sector emissions of greenhouse gases; tem away from sustainability. We have done this to an 3. Water quality, number of species endangered, soil extent, but for those unfamiliar with this area further protection, and so forth; discussion may be useful. 4. Acres of revitalized urban area and reclaimed brownfield sites; 5. Trip making and miles traveled (by mode); Diminishing Petroleum Reserves 6. Reliance on single-occupant vehicles; 7. Access to jobs and services for the transport-dis- It is generally recognized that in the 100 or so years of advantaged; and motor vehicles using gasoline as a fuel, the world has 8. Population in areas that attain national atmo- consumed approximately 1 trillion barrels of petroleum spheric air quality standards. for this and other purposes--all of this at a time when only a small proportion of the population of that world The list includes several variables relating to behav- had access to such vehicles or other uses for petroleum ioral aspects of travel and transport, perhaps with the energy. The major question at this point is, what is the idea that voluntary action by drivers may be critical in future demand for this fuel and will the Earth be able to making the transport system more sustainable. It is not supply it? Given that the developing world is expected clear how far this effort went, but it involved several to increase its demand for energy in transport and other agencies of the federal government at the time. sectors, which has already begun, global demand will Litman (n.d.) proposed a different set of sustainable increase significantly. transport indicators that is based more on personal or What can be said of supplies? The optimist would household travel characteristics. The following are say that there are about 2 trillion barrels of recoverable included in his list of indicators: conventional petroleum reserves out there. In general, production keeps pace with demand, but if the latter 1. Average portion of household expenditures increases significantly, it is likely that additional pro- devoted to transport; duction will have to take place. At present consump- 2. Average amount of residents' time devoted to tion exceeds new discoveries by more than a 3:1 ratio. nonrecreational travel; Some scholars believe we have found all of the major 3. Per capita automobile mileage; fields in the world. The discovery of more major fields 4. Ability of nondrivers to reach employment cen- (perhaps in the South China Sea) will probably only ters or services; enable the world to fight a delaying action (Deffeyes 5. Per capita land area paved for roads and parking; 2001). Others would say that the conventional sources 6. Quality of pedestrian and bicycle facilities; will not last beyond 2020 and that there is significantly 7. Quality of public transit (frequency, speed, safety, more petroleum out there, but it is found in unconven- and so forth); tional sources (Greene et al. 2003). Such sources would 8. Special transit services and fares relative to low include shale oil, oil sands, and tar sands. Estimates are income; that shale oil is substantially more expensive to pro- 9. Transit coverage, residents within 0.5 kilometer; duce and deliver, while the others have costs that are 10. Motor vehicle accident fatalities; comparable with those of conventional sources. 11. Per capita transport energy consumption; Depending on what the actual costs are, we will see the 12. Medical costs attributable to transport; slower or faster development of alternative fuels. In the 13. Publicly financed transport costs; and final analysis our current transport systems are nonsus- 14. Residents' role in transport and land use decisions. tainable because at least at present they use a fuel that is finite and nonrenewable. This is true whether we are Broadly speaking, these are representative of the talking about conventional or unconventional sources approaches that have been taken to define or indicate of petroleum.

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38 I N T E G R AT I N G S U S TA I N A B I L I T Y I N T O T H E T R A N S P O RTAT I O N P L A N N I N G P R O C E S S Global Atmospheric Impacts micrometers in diameter) and 31 percent of PM2.5], and 33 percent of volatile organic compounds. A sub- Some researchers believe that humans are placing emis- stantial portion of the production of urban ozone also sions into the atmosphere that will eventually have has its origin in mobile sources. The various pollutants impacts on the global climate. Others believe these must be viewed as contributors to nonsustainability, and impacts have already begun with increasing global tem- they are viewed as such in Europe and by the Organisa- peratures and a rise in sea level. The emissions, some- tion for Economic Co-operation and Development times called greenhouse gases, may lead to a forcing or (1998). They have not always been viewed as part of the an enhancement of the greenhouse effect. This is the sustainability problem in the United States, but this may effect that under normal conditions enables the planet be because these problems were and are being to sustain enough heat to make it amenable to life. More addressed. This attitude seems to have changed in recent specifically, the burning of fossil fuels has released sub- years. stantial amounts of carbon dioxide, a greenhouse gas, The negative health impacts of these emissions, pri- into the atmosphere, and this will lead to a forcing or an marily on the human respiratory system, must be viewed increase in the global average temperature. As of 2001 as a significant problem that cannot be allowed to con- carbon dioxide concentrations have increased 31 per- tinue. The United States has made substantial progress cent over levels in 1750. These levels are now higher in reducing the significance of these emissions, and some than they have been in the past 420,000 years (Inter- believe they will cease to be a significant problem in the governmental Panel on Climate Change 2001). Trans- foreseeable future. Nevertheless, at this time these emis- portation and the use of petroleum-based fuels are sions are one of the factors making transport systems responsible for just over 20 percent of these emissions as nonsustainable. of 2003. This is nonsustainable according to the 2004 World Energy Outlook of the International Energy Agency. Fatalities and Injuries One might reasonably ask whether the warming will create major problems or will be only a minor inconve- It should be an accepted premise that a transport system nience. We really don't know the answer, but the con- that kills off its users is not sustainable. However, many sensus is that the negative impacts of only a minor policy makers do not want to include fatalities and change in temperature could be substantial. There is a injuries in the calculus of nonsustainability factors. Indi- tendency among many sectors to want to ignore the cations are that the world's motor vehicle fleet is respon- impacts on the planet. This may be possible for some sible for nearly 1 million fatalities each year and sectors, but it is not so easy for transport. The flooding probably 70 million or more injuries (World Health of transit tunnels due to a rise in sea level, the failure of Organization 2001 as cited by Evans 2003). Global airplanes to take off due to high temperatures, the buck- forecasts of fatalities for the next 10 years are almost ling of highways and railroad track due to heat, the beyond comprehension. flooding of coastal highways and railways, and the sub- Fatalities per vehicle mile are dropping in the United mersion of dock facilities are not problems that can be States, but that is probably due primarily to increases in dismissed easily. Even more important is the potential vehicle miles driven. Until recently total fatalities were shift in agricultural production to new areas with mod- also dropping, but the latter appear to be increasing erate climates and away from areas that are too hot or now or at least leveling off. We are no longer sure what too dry, which would result in the need to relocate trans- is happening with injuries. port infrastructure in such areas (Black 1990). Congestion Local Air Quality Impacts Policy makers in general do not view congestion as a The contribution of motor vehicle emissions to the major barrier to transport sustainability. Even this con- problem of poor air quality is significant. This must also ference is giving it rather short shrift. The reason is not be seen as something that makes current transport sys- at all clear, although it may be attributable to the indi- tems nonsustainable. As of 2000, according to the rect nature of the impacts generated. Congestion Bureau of Transport Statistics, mobile sources decreases the speed of vehicles and results in lower fuel accounted for 7 percent of sulfur dioxide emissions, 43 efficiency. It increases emissions that are detrimental to percent of nitrogen oxide emissions, 51 percent of car- both the global and the local environments. It increases bon monoxide emissions, approximately 9 percent of motor vehicle incidents, while it decreases fatalities. Per- particulates [2 percent of PM10 (particles up to 10 haps it was viewed as a manifestation of all the other