Sustainable Transport Indicators: Energy, Emissions, and Safety in Canada (1990-2000), Study notes of Architecture

Download Sustainable Transport Indicators: Energy, Emissions, and Safety in Canada (1990-2000) and more Study notes Architecture in PDF only on Docsity! Sustainable Transportation Performance Indicators Page 1 Sustainable Transportation Performance Indicators About this document This 18-page document is built around one-page descriptions on Pages 2-15 of each of the initial set of 14 sustainable transportation performance indicators (STPI) developed by the Centre for Sustainable Transportation. Page 16 summarizes the 14 STPI, draws some conclusions, and suggests what the STPI could be used for. Pages 17 and 18 contain a glossary that explains the words and phrases that are italicized and in this colour the first time they appear on a page. Who this document is for This document could help anyone who wants to find out more about sustain- able transportation and about perform- ance indicators. More detailed reports on the STPI work can be found at the Centre’s Web site (see below). Sustainable transportation One of the first things the Centre did when it was founded in 1996 was de- velop a vision and definition of sustain- able transportation. The vision can be found at the Centre’s Web site. The definition of a sustainable transporta- tion system is in the box on Page 18. With slight changes, it has been adopted as a working definition by the Transport Ministers of the 15 countries of the European Union. Indicators Indicators are numbers that tell a story about things of significance. Canada’s unemployment rate is an indicator. Over time it tells something about how well Canadians are doing. Another indicator is the Consumer Price Index, which tells us whether frequently purchased items are becoming more or less expensive. How the STPI were developed Four criteria were used in selecting the numbers that make up each of the 14 STPI. The numbers had to be relevant to the definition, a time series, represent all of Canada, and come from a reliable source. Sometimes available data were used directly as the indicator (e.g., Indi- cator 1). Sometimes an index was cre- ated from several sets of data (e.g., Indi- cator 3). Each indicator has been put in the form of a simple graph showing how it has changed across recent years. When the direction of the graph is downwards, progress has been made towards sus- tainable transportation, and vice versa. Development of this initial set of STPI has been limited by what was possible given available data. As more and better data are collected, improved and new STPI will be developed. The Centre for Sustainable Transportation Le Centre pour un transport durable For more information about the Centre for Sustainable Transportation and about STPI, visit the Centre’s Web site at www.cstctd.org. PHOTO CREDITS: DENNIS SYMK (top); MICHAEL ROSCHLAU; MICHAEL ROSCHLAU; ANITA WASIATA; VWVORTEX.COM (bottom) Sustainable Transportation Performance Indicators Page 2 About this indicator A sustainable transportation system is one that “minimizes consumption of non-renewable re- sources” (see Page 18). A good indicator of progress towards sustainable transportation is thus one that shows consumption of non-renewable resources by transport. When this consumption goes down, there is progress towards sustainable transportation. The main resource used for transport in Canada is the petro- leum from which vehicle fuels such as gasoline, diesel fuel, and kerosene are refined. Other resources are used, including many metals, but in much smaller quantities. The petro- leum products are fossil fuels. They are not renewable. Fuels are used for the energy they provide. Almost 100% of the energy used for transport in Canada comes from burning fossil fuels in internal combustion engines and aircraft jet engines. Indicator 1 shows yearly consumption of energy for transport in Canada from 1990 to 2000 in petajoules. Because almost all this energy comes from fossil fu- els, the indicator reflects the use of non-renewable resources. The indicator could have shown the actual amounts of fuel used. But this would not have taken into ac- count the energy contents of the different fuels. For example, diesel fuel contains more usable energy per litre than gasoline, which is partly why diesel engines use less fuel per kilometre. What this indicator shows Energy use for transport in Canada increased by 21.5% between 1990 and 2000, from 1,878 to 2,282 petajoules. This represents a large increase in the con- sumption of non-renewable resources for transport. It thus indicates movement away from sustainable transportation. Progress towards sustainability would have required a reduction in the consumption of non- renewable resources. There was a reduction in energy use for transport between 1990 and 1991. This change was in the direction of sustainability. Energy use then increased, al- though the 1990 level was not passed until 1994. Additional comments A contributing factor to the in- crease in transport energy use was population growth. Can- ada’s population grew by 11.2% between 1990 and 2000. Thus, if all else had stayed the same, transport energy use would have increased by 11.2%. But Canadians travelled more and moved more freight. Amounts of motorized travel per person in- creased by 3.2%. Amounts of movement of freight per person increased by 23.3%. (See Indicators 5 and 6 for the overall increases in motorized travel and freight movement.) Offsetting these factors were reductions in energy intensity (see Indicator 13). Between 1990 and 2000, energy use per person-kilometre fell by 1.8%. Energy use per tonne-kilometre fell by 2.2%. 1,700 2,000 2,300 1990 1995 2000 T ot al e n er g y us e (P J) Indicator 1 shows a rise in energy use for transport. This represents an increase in the use of non-renewable fossil fuels, and thus movement away from sustainability. S T P I Indicator 1 Energy use for transport PHOTO CREDIT: CALIFORNIA ENERGY COMMISSION Sustainable Transportation Performance Indicators Page 5 About this indicator A sustainable transportation system is one that “allows the basic access needs of individuals to be met safely”. A good indicator of progress towards sustainable transportation is thus one that shows inju- ries and fatalities from transport. When injuries and fatalities decline, there is progress towards sustain- able transportation. Here, the focus is on injuries and fatalities from road transport, which comprise almost 90% of all transport fatalities and almost 100% of all transport injuries. Road injuries and fatalities have changed in different ways over time. Injuries have tracked road-vehicle collisions. The totals for Canada reached a peak in 1987 and have declined steadily since then. Total road fatalities reached a peak in 1973. Because injuries and fatalities have changed in different ways, and be- cause both are important aspects of safety, an index was constructed to show how both changed over time. The index reflects the approximate 70:1 ratio of injuries to fatalities during the 1990s. To create the in- dex, they were weighted so that each fatality was equivalent to 70 injuries. The results were then adjusted so that the 1990 value equalled 100. A value of the index below 100 repre- sents progress towards sustainable transportation. What this indicator shows The index fell more or less steadily throughout the 1990s, with a total decline by 21.8% between 1990 and 2000. The decline in the index represents a decrease in inju- ries and fatalities from road transport. It thus indi- cates progress towards sustainable transportation. Additional comments Note that the term ‘collisions’ is used rather than ‘accidents’. This is done increasingly—for example, in government statements and media traffic reports— to stress the point that such incidents are preventable. The decline in emissions occurred in spite of large increases in the amount of transport activity (see Indicators 5 and 6). Contributing factors to the declines in road injuries and fatalities have been drink-driving laws, seat-belt laws, safety features in vehicles (e.g., airbags and better brakes), and safety features in highway de- sign (e.g., better alignments and signage). Enforcement of speed restrictions and safe-driving re- quirements is an important factor. Inclusion of Indicator 4 in this set of indicators has been controver- sial. Many people argued that matters of safety are immediate concerns and are not relevant to sustain- ability, which is more to do with the medium and long term. It was nevertheless included because an unsafe system is not sustainable. 70 80 90 100 110 1990 1994 1998 In ju rie s an d fa ta lit ie s (1 99 0= 10 0) Indicator 4 shows a decline in injuries and fatalities from road transport, and thus progress towards sustainable transportation. S T P I Indicator 4 Injuries and fatalities PHOTO CREDIT: EUGENE HIRT Sustainable Transportation Performance Indicators Page 6 About this indicator The definition of a sustainable transportation system does not directly address whether more or less movement of people is required for sustainability. On the one hand, there are circum- stances where movement of people can be desirable. For example, travel can help with learning about other people and other places. When movement is non-motorized, e.g., walking or bicycling, it can result in good health. Moreover, when move- ment is in well-occupied, electrically powered urban transit, it can result in low levels of impact on the environ- ment. On the other hand, most of the movement of Canadians today is in motorized vehicles, particularly in various kinds of personal vehicle. As this movement increases, the unsus- tainable effects of transport tend to increase. Indicators 5-8 have been included in the present set to reflect different aspects of transport activity. Indicator 5 shows the total motorized movement of people within Canada in person-kilometres. In 2000, 74.3% of this travel was by personal vehi- cle, 17.1% was by air, 3.9% was by urban transit, 2.7% was by school bus, 1.8% was by inter-city bus, and 0.3% was by inter-city rail. What this indicator shows Motorized movement of people increased by 14.7% between 1990 and 2000, from 509 to 583 billion person- kilometres. Because of the pat- tern of travel—mostly by auto- mobiles and air—such an in- crease in transport activity ad- versely affects the environment. It thus indicates movement away from sustainable transportation. Progress towards sustainability would have required a reduction in the amount of movement of people. There was a reduction in the amount of movement of people between 1990 and 1991, al- though the 1990 level was passed in 1992. There was little growth in travel after 1998. Additional comments The main contributing factor to the increase in the movement of people has been the increase in Canada’s population, which grew by 11.2% between 1990 and 2000. There was also a small increase (3.1%) in the amount of travel per person. The decline in travel in 1991 may have been the result of the economic recession in that year. The levelling off from 1998- 2000 has no easy explanation. 480 520 560 600 1990 1995 2000 B ill io ns o f p er so n -k ilo m et re s Indicator 5 mostly shows increased movement of people. Present transport patterns mean this represents movement away from sustainability. S T P I Indicator 5 Movement of people PHOTO CREDITS: CHRIS LAWRENCE (top); DANNY HILL; JASON SHRON; MARTIN PARSONS (bottom) Sustainable Transportation Performance Indicators Page 7 environment, and could also represent increased costs to business. It indicates movement away from sus- tainable transportation. Progress towards sustainabil- ity would have required a reduction in the amount of movement of freight. There was a reduction in the amount of movement of freight between 1990 and 1992, although the 1990 level was then passed in 1994. Additional comments The main contributing factor was the growth in road freight, by 94.3% be- tween 1990 and 2000. Contributing to this increase were growth in the econ- omy and growth in the use of ‘just-in- time’ methods. Adding together the tonne-kilometres of freight movement by different modes, as has been done for this indi- cator, is sometimes criticized because the modes are often not interchange- able. Trucks can reach many more lo- cations than the other modes. Indeed, freight journeys by the other modes usually involve some movement by truck. The average value of the goods carried varies greatly among the different modes. Air freight typically has more than 50 times the value per tonne of road freight, which in turn has more than three and five times the value of freight carried by rail and wa- ter. Air freight also uses much more energy than the other modes, followed by road, water, and rail. About this indicator The definition of a sustainable transportation system does not directly address whether more or less move- ment of freight is required for sustain- ability. On the one hand, when businesses are more active there is more freight trans- port (e.g., goods moving from factories to warehouses to stores). When goods can be moved easily, businesses can do better. On the other hand, the movement of freight—like the movement of people, uses energy and causes globally acting and locally acting emissions. As well, freight transport is a cost to business. It’s good for businesses to try and re- duce their need for freight transport, as long as this can be done without reduc- ing the efficiency with which they oper- ate. Thus, on balance, reductions in the movement of goods represent progress towards sustainable transportation. Indicator 6 shows the total motorized movement of freight within Canada in tonne-kilometres. In 2000, 43.9% of this movement was by rail, 28.7% was by water, and 27.4% was by road. A very small amount, less than 0.1%, was by air. What this indicator shows Movement of all freight increased by 37.1% between 1990 and 2000, from 541 to 741 billion tonne- kilometres. Such a large increase represents consider- able growth in the adverse effects of transport on the 500 625 750 1990 1995 2000 B ill io n s of to n ne -k ilo m et re s Indicator 6 shows substantial growth in the movement of freight. Because of freight’s impacts and costs, this represents movement away from sustainable transportation. S T P I Indicator 6 Movement of freight PHOTO CREDITS: ROB EULL (top); JAY PIBOONTUM (bottom) Sustainable Transportation Performance Indicators Page 10 Per-person measures are not often used when sustain- ability is a consideration because the environment responds to actual rather than relative impacts. How- ever, an exception is made here because the key fac- tor may be whether the geographic growth of an ur- ban region occurs at a higher rate than population growth. Also, land used per person is the inverse of residential density, often used to describe urban re- gions. What this indicator shows Between 1971 and 1996, the amount of developed land per urban resident increased by 28.9%, from 971 to 1,251 square metres. Almost none of the increase occurred between 1971 and 1981. The highest rate of growth occurred between 1991 and 1996. Because of the strong links be- tween increased land use and increased transport activity, this growth indicates move- ment away from sustainable transportation. Progress to- wards sustainability would have required a reduction in land used per person. Additional comments The total amount of land used for urban purposes in- creased by 55.7% between 1981 and 1996, from 18,015 to 28,045 square kilometres. The increase cor- responds to about 1.4% of Canada’s agricultural land. Urban sprawl is often thought of in terms of residen- tial development. But low-density commercial and industrial development may be just as responsible for the extravagant use of land. About this indicator A sustainable transportation system is one that “minimizes the use of land”. Transport uses land di- rectly, as shown by Indicator 10. Of greater impor- tance may be how transport allows the development of urban areas at increasingly low residential densi- ties, a process often known as urban sprawl. Widespread ownership of personal vehicles makes development possible at densities too low to justify bus services. People who live in such development need to use their cars for almost all the journeys they make. This leads to more car ownership and use and more sprawl. The result is growth in the use of land for urban purposes (homes, busi- nesses, institutions, etc.) be- yond the rate of population growth. In addition, low- density development can make rural areas less accessible to urban residents, causing them to travel farther for recreation. Excessive use of land for urban purposes can displace agricul- tural activity, requiring food to be shipped from greater distances. Use of land for urban purposes has several adverse impacts. It alters drainage patterns, changes surface reflectivity, destroys ecosystems, and generally inter- feres with other species’ use of the land. Thus, a good indicator of progress towards sustain- able transportation is the amount of land used for ur- ban purposes. When this declines, there is progress towards sustainable transportation. Indicator 9 shows urban land used per urban resident. 900 1,100 1,300 1971 1981 1991 P er -c ap ita la n d us e (m 2 / re si d en t) Indicator 9 shows an increase in the amount of urban land used per person. This can result in more transport activity and thus movement away from sustainability. S T P I Indicator 9 Urban land use Sustainable Transportation Performance Indicators Page 11 more land taken for transport, and more traffic, this increase indicates movement away from sustainabil- ity. Additional comments More than other indicators in this set, this indicator should be used with caution. There are only four data points, and there is some question as to whether the data for these four points were col- lected in a uniform manner. The indica- tor is included, nevertheless, because of the importance of the topic and the need to represent some aspect of trans- port infrastructure. Data about roads are now being col- lected using aerial photography in con- junction with Geographical Informa- tion Systems that result in precise meas- urements of road length and width. Use of these data will mean that there can be greater confidence in the indicator. Paved roads comprised only about a third of all road capacity in Canada in 1995. The total was just over 900,000 two-lane-kilometre equivalents. How- ever, almost all traffic is on paved roads. The amount of unpaved road- way—mostly with gravel surfaces— has been declining, so that the total of all road capac- ity has remained almost constant. More than half of Canada’s unpaved road capacity is found in Alberta and Saskatchewan. Considering paved roads alone, the growth in road capacity between 1985 and 1995 (23.6%) was just a little more than the growth in the number of regis- tered road vehicles (20.8%). About this indicator A sustainable transportation system is one that “minimizes consumption of non-renewable re- sources” and “minimizes the use of land”. This indi- cator—length of paved roads in Canada—touches on both of these requirements. Road construction and maintenance require energy, which comes mostly from non-renewable fossil fuels (also see Indicator 1). Roads also use land, already addressed in part by Indicator 9. Another feature of roads is that they can generate traffic. In a large urban area, more roads mean more traffic be- cause limited road space helps limit the amount of traffic. Where road capacity does not limit traffic, adding road space would result in inefficient use of infra- structure. It would be contrary to an- other part of the definition, which says that a sustainable transportation system “operates efficiently”. Thus, in several ways, additional road capacity in Canada generally represents movement away from sustainable transportation. This may not be true everywhere, even in Canada. Certainly in some poorer countries, adding proper roads can produce improve- ments in the movement of people and freight that offset the roads’ negative impacts. What this indicator shows Length of paved roads in Canada increased by 23.6% between 1985 and 1995, from 243,800 to 301,300 two-lane-kilometre equivalents. Because added road capacity can mean more energy use for construction, 230 270 310 1985 1990 1995 T ho us an ds o f 2 -la n e ki lo m et re s Indicator 10 shows an increase in paved road capacity. This represents more land and energy use, and can stimulate traffic, indicating movement away from sustainability. S T P I Indicator 10 Length of paved roads Sustainable Transportation Performance Indicators Page 12 2000. The increase involved two steep rises: between 1982 and 1986, and between 1998 and 2000. Transport consumed more of household income and probably became less affordable over this period. Given that affordability is one of the requirements of a sustainable transportation system, this trend would appear to be movement away from sustainability. Additional comments Closer analysis of the household spending data shows that what increased the most were the costs of car purchase and other fixed costs, e.g., insur- ance. Real spending on fixed costs—mostly car purchase— increased by 69.2% between 1982 and 2000, with most of the increase occurring between 1982 and 1986 and between 1996 and 2000. Real spending on operat- ing costs, mostly fuel, declined by 0.8% between 1982 and 2000. In 2000, average household spending on personal vehicles totalled $6,906 ($4,430 on fixed costs, $2,476 on operating costs). Average spending on ur- ban transit was $216, and spend- ing on other purchased transport, mostly by air, was $454. On average, just over 90 minutes of each day’s em- ployment is dedicated to paying for the costs of own- ership and operation of personal vehicles. Canadians’ average commuting time is just over 60 minutes (i.e., about 30 minutes each way). About this indicator A sustainable transportation system is by definition “affordable”. Thus, other things being equal, a good indicator of progress towards sustainable transporta- tion is one that shows household spending on trans- port in relation to available income. There is a problem here. If transport is too cheap, too much of it could be used. With present patterns of transport activity, this would not represent progress towards sustainability. On the other hand, another feature of a sustainable transpor- tation system is that it “allows the basic access needs of indi- viduals to be met”. If transport is expensive, poorer people may have inadequate access. More- over, if half of the average household’s after-tax spending went towards transport, little would remain to meet other im- portant needs. Indicator 11 shows the share of households’ after-tax spending going to transport. This share does not necessarily represent the affordability of transport. If it goes up, it could mean that more transport is being consumed rather than transport is less af- fordable. However, we know from other indicators that the changes in transport activity in relation to population growth have been small (see Indicators 5 and 8) except for freight movement (see Indicator 6). What this indicator shows The share of household spending on transport in- creased from 16.1% to 19.2% between 1982 and 16 17 18 19 20 1980 1985 1990 1995 2000 P er c en t o f a ll sp en di ng o n tr an sp or t Indicator 11 shows an increase in the share of household after-tax spending going to transport, which thus became less affordable and less sustainable. S T P I Indicator 11 Household spending CARTOON BY ANDY SINGER Sustainable Transportation Performance Indicators Page 15 formance of road vehicles and progress towards sus- tainable transportation. Additional comments As noted in the discussion of Indicator 3, the reduc- tion in emissions intensity resulted in an overall re- duction in locally acting emissions during the first half of the decade. During the second half of the dec- ade, the technological improvement shown by Indica- tor 14 was largely offset by increases in transport activity. This meant that although each vehicle produced less pollution, there was as much pollution because there were more vehicles on the road. Also as noted in connection with Indi- cator 3, the main technological im- provement was the penetration of the three-way catalytic converter through- out the gasoline-fuelled vehicle fleet. Other improvements to engines and emissions control devices helped re- duce emissions from gasoline and die- sel fuelled vehicles. The picture of the truck is misleading in that Indicator 14 does not represent emissions of particulates, which in- clude the soot that blackens the ex- haust. The reason for this omission is noted in the discussion of Indicator 3. (The picture is also mis- leading in that most trucks do not produce soot in this way.) About this indicator This indicator is concerned with the technical per- formance of road vehicles, specifically their locally acting emissions per unit of transport activity. It pro- vides detail about an aspect of Indicator 3, which concerns locally acting emissions from all road vehi- cles. Indicator 14 also concerns all road vehicles. To allow for many differences among these vehicles—which range from motorcycles and ‘economy’ cars to buses and large trucks—locally acting emissions were related to the vehicles’ energy use. An example would be the amount of ni- trogen oxides emitted per megajoule of energy consumption. This is known as the emissions intensity for this pol- lutant. Rating the various road vehi- cles in this way makes it possible to create a weighted average for all the types of vehicle. There was also the problem of com- bining the results for the different kinds of pollutant. This was solved in the manner used for Indicator 3, by further weighting so that that the re- sulting index fairly reflects changes in each one of the four pollutants. Finally, the index was set at 100 for 1990. Values of the index below 100 represent progress towards sus- tainable transportation. What this indicator shows The index fell by 25.7% between 1990 and 2000. This represents a substantial improvement in the per- 70 80 90 100 110 1990 1995 2000 E m is si on s p er u n it of en er gy u se (1 99 0= 10 0) Indicator 14 shows a decline in the overall emissions intensity of road vehicles, and thus progress towards sustainable transportation. S T P I Indicator 14 Emissions intensity ILLUSTRATION CREDITS: UNION OF CONCERNED SCIENTISTS (top); NEW BRUSWICK ENVIRONMENTAL NETWORK (bottom) Sustainable Transportation Performance Indicators Page 16 INDICATOR Progress? Indicator 1 shows a rise in energy use for transport. This represents an increase in the use of non-renewable fossil fuels, and thus movement away from sustainability. Indicator 2 shows an increase in greenhouse gas emissions from transport. This represents movement away from sustainable transportation. Indicator 3 shows a decline in locally acting emissions—and thus progress towards sustainable transportation—although mostly in the early 1990s. Indicator 4 shows a decline in injuries and fatalities from road transport, and thus progress towards sustainable transportation. Indicator 5 mostly shows increased movement of people. Present transport patterns mean this represents movement away from sustainability. Indicator 6 shows substantial growth in the movement of freight. Because of freight’s impacts and costs, this represents movement away from sustainable transportation. Indicator 7 shows the share of all movement of people by more polluting as opposed to less polluting modes. There has been no clear trend in this share. Indicator 8 mostly shows growth in the movement of personal vehicles. Present transport patterns mean this represents movement away from sustainability. Indicator 9 shows an increase in the amount of urban land used per person. This can result in more transport activity and thus movement away from sustainability. Indicator 10 shows an increase in paved road capacity. This represents more land and energy use, and can stimulate traffic, indicating movement away from sustainability. Indicator 11 shows an increase in the share of household after-tax spending going to trans- port, which thus became less affordable and less sustainable. Indicator 12 shows an increase and then a decrease in relative transit costs, indicating move- ment away from then towards sustainable transportation. Indicator 13 shows initial increases in the energy intensity of cars and trucks, representing movement away from sustainable transportation. Indicator 14 shows a decline in the overall emissions intensity of road vehicles, and thus progress towards sustainable transportation. Conclusions from the initial set of STPI The above table pulls together the summaries for the indicators at the bottom of Pages 2-15. In the summa- ries, ☺ shows progress towards sustainable transpor- tation, shows the opposite, and shows some- thing in between. The many sad faces—for Indicators 1, 2, 5, 6, 8, 9, 10, 11, and 13—suggests that trans- portation in Canada has been mostly moving away from sustainability, although very recent trends in a few of these (5, 8, 13) indicate improvement. Some indicators (3, 4, 14) show that progress has been made towards sustainable transportation. What the STPI can be used for The primary reason for developing the STPI was to provide a means of tracking whether transport in Canada is becoming more like the definition on Page 1. The STPI can be used from year to year to figure out whether this is happening. They can also tell us about the effects of government policies, by looking at how specific STPI change after the policies are implemented. As well, they can help shape new poli- cies, by showing the kinds of change that the policies should produce. The STPI can also guide the private sector, by showing what is needed for sustainability. Sustainable Transportation Performance Indicators Page 17 access: People need access to other people, services, and goods. Travel is usually a means to access. Sustainability means good access with less travel. affordable: A person finds something affordable if it can be paid for without limiting expenditure on (other) essen- tial items such as food and accommodation. after-tax spending: What a household spends, not counting federal and provincial income-tax and associated payments. air pollution: Substances in the air at concentrations that are harmful to living things. carbon dioxide: The main greenhouse gas from human activity, produced whenever a substance containing carbon burns completely in the air. carbon monoxide: A poisonous gas resulting from the incomplete combustion of a substance containing carbon. contributing factor: A better term than ‘cause’ when discussing complex matters such as transport because sim- ple ‘cause-and-effect’ relationships are often not evident. ecosystem: A group of interacting, often interdependent living organisms, as small as the underside of a leaf and as large as the Earth. energy: This fundamental concept in physics refers to the capacity to do work, i.e., to move an object through space, or raise temperature. fixed costs: These include the costs a car owner pays no matter how much the car is used. Examples are car loan payments, annual licence fee, and insurance. fossil fuels: Hydrocarbon fuels derived from the remains of animal or vegetable life in past geological ages. They include oil, natural gas, and coal. The term ‘petroleum’ is used to refer to the first and sometimes the first two of these. Geographical Information System: One of a variety of methods involving digital referencing of information in ways that allow computers to display and exploit spatial relationships. globally acting emissions: These are substances put into the air that affect the whole planet. The two main examples are greenhouse gases, which can change the Earth’s cli- mate, and ozone-depleting substances, which destroy the shield of ozone in the upper atmosphere that protects living things from the sun’s ultraviolet rays. They are distin- guished from locally acting emissions. greenhouse gases (GHGs): A gas such as carbon diox- ide that raises the temperature of the Earth’s surface by trapping its thermal radiation. ground-level ozone: Ozone is a highly reactive form of oxygen. Ozone is unwanted near the surface of the Earth— where it is the main constituent of smog—because it harms living things. It is wanted high up in the atmosphere, where it absorbs harmful ultra-violet radiation. Ground-level ozone is not a vehicle exhaust gas but a product of the ac- tion of sunlight on these gases. index: A measure that combines data from several sources to provide an overall picture of how they are changing. The Consumer Price Index (CPI) is an example. It shows how the price of a ‘basket’ of goods varies, selected so as to represent what consumers buy. Often, as with the CPI, the index is constructed so that the value for a particular year is 100. This makes it easy to compare changes across years. infrastructure: Transport infrastructure comprises the physical things other than vehicles that make transport possible, including roads, rail tracks, and airports. ‘just-in-time’ methods: These require producers of components to deliver them exactly when they are required for use in manufacturing a product. The manufacturer does not have to keep stocks of the components, but more fre- quent deliveries are required and thus more transport activ- ity. locally acting emissions: These have effects over a lim- ited geographic area. They include the components of air pollution. megatonnes of CO2 equivalent: A way of expressing emissions of several kinds of GHG in terms of the most common GHG, namely carbon dioxide. (This is actually an index.) nitrogen oxides: Several harmful gaseous compounds of nitrogen and oxygen produced whenever anything is burned in air, as is the fuel in an internal combustion en- gine. non-renewable resources: These can be noticeably diminished by human activity because the amounts on the Earth are fixed and relatively small (e.g., copper), or be- cause the amounts are relatively small and renewed much more slowly than the rate at which they are used (e.g. fossil fuels). By contrast, the use of renewable resources, e.g., wind, does not affect their future availability. operating costs: These vary with the amount of use and, for automobiles, include gasoline, oil, parking, and mainte- nance. particulates: Specks of carbon produced when fossil fuels are burned, often small enough to penetrate deep into the lungs. They can be harmful in themselves and have harmful substances attached to them. person-kilometre: One person moving through one kilo- metre. Thus, the movement of ten persons through five /continued overleaf GLOSSARY