Articles > Andrew Dzurik

Mass Transit and Sustainable Urban Environments
Andrew Dzurik, Danuta Leszczynska and Angela Brenner National Urban Transport Institute, USA

MASS TRANSIT FOR SUSTAINABLE URBANIZATION
The rapid rate of urbanization in the 20th century has magnified the overall impacts of cities on local and global environments. Closely linked land use and transportation patterns account for much of urban sprawl, especially in the more developed countries where private automobile ownership is common. In the United States, for example, over 160,000 hectares of farm land are taken each year for urban development (Lockwood, 1999). Because of increasing dependence on the automobile throughout the world, transportation has become the fastest-growing major contributor of greenhouse gas emissions and of land conversion to urban uses. Greater reliance on walking and bicycles could help to curb air pollution, greenhouse gases, and land conversion, but significant increases in the use of urban mass transit is a more likely path to sustainable urbanization. By observing the experiences of urban areas in the more developed countries, the developing world can pursue policies and development patterns that will lead to more sustainable urban areas.

Increasing attention has been given to urban sustainability over the past decade, but there is no fully accepted definition of sustainable development or sustainable urbanization. For purposes of this paper, sustainability is defined as protection of working lands and urban communities from adverse development effects with respect to human health and the environment. In particular, this paper focuses on modern technology and its applicability to mass transit systems as major contributors to sustained urbanization in developing countries.

There is no question that urban sprawl is closely linked to the use of the private automobile and to a variety of environmental and social problems. In contrast to sprawl, many people throughout the world have viewed land as a scarce commodity to be protected and used wisely. Increased mass transit use and controlled or decreased automobile use can help to alleviate many of the problems of sprawl, particularly environmental, health and social effects (Kenworthy, 1996). Most developing countries have yet to reach a high level of automobile ownership, although they are experiencing rapid urban growth. As economies develop, however, there is a tendency for more private automobiles. Thus, investment in effective urban mass transit systems can be an important tool in making wise use of the land in the face of increasing urbanization.

There is a need to improve urban transportation infrastructure in both developed and developing countries in order to provide fast and efficient transportation alternatives, and to minimize the potential environmental effects of the automobile. Certain transportation systems, such as subway and light rail, may appear to be an ideal solution, but such systems are costly and tied to fixed routes. Thus, cities should do careful planning and budgeting in order to avoid making the costly mistakes of choosing an inappropriate form of mass transit. Lower-cost solutions, such as buses, may prove to be the best answer for cities in developing countries, especially in the early stages of urbanization.

Of the various options available for public transportation, efficient bus systems can be effective and affordable. Although taking no more roadway space than two cars, buses can carry as many as 80 passengers in peak hours (Asif Faiz, et al., 1990). Nevertheless, many existing bus systems are outdated, noisy, uncomfortable and polluting, so it is important to look at new technologies as cities seek to improve their mass transit systems. Investment in public mass transit has shown to attract new users by making it easy to use and competitive with the automobile (Bolade, 1993). This is especially important in urbanizing, developing countries, where new transit users are likely to be former pedestrians or bicyclists.

Mass transit technologies continue to evolve and improve in many ways. This paper discusses three major categories of technology as contributing factors in mass transit systems that together produce a more user friendly, environmentally friendly, health conscious and less costly means of public transportation. The three categories are communications, energy, and materials, particularly as they apply to bus transit systems.

EMERGING INFORMATION AND COMMUNICATIONS TECHNOLOGY
Information and communications technology can contribute to reliable, efficient and environmentally acceptable mass transit systems that are consistent with sustainable urban development. Options include rapid transit automated vehicles, real time user information, automated fare collection, vehicle tracking and passenger counters.

Automated Vehicles. Some cities are beginning to consider mass transit systems that make use of automated vehicles. For example, the Chicago Transit Authority has discussed rapid transit bus systems with no on board operator. Instead, intelligent optical devices are installed, which act as ‘eyes’ to direct the bus on the right path. (http://www.enn.com...4692.asp). This creates an environment that promotes consistency and reliability. Unlike operator-driven buses, these intelligent optical devices do not need coffee breaks and can’t call in sick. Such automated vehicles will give urban transit users security of knowledge that they can count on the transit system for every trip they make.

Vehicle Tracking Systems. A common complaint with mass transit is the amount of waiting time and the uncertainty of knowing when the next vehicle will arrive. Advanced communications technology makes it possible to track each vehicle en route and then calibrate arrival times at specific stops. This tracking is done by global positioning systems that combine satellite and computer-based tracking systems. In the last four years, vehicle-tracking use has increased by more than 200%. In addition to providing real-time operating information to operators and passengers, tracking systems can determine emergency locations of vehicles, take corrective actions to deviations in service, and use collected data for planning and management. Tracking systems can also improve spacing of vehicles and thus contribute to improved convenience and reliability (http://www.fta...html).

Real Time Passenger Information Systems. Several technologies are available or soon to be available in which passengers can obtain real time information on predicted arrival times, departure times, and delays of various modes of public transportation. An example is San Francisco Bay Area’s “Next Bus Information Systems.” This technology utilizes vehicle-tracking systems discussed previously and incorporates those predicted arrival, departure and delay times with real time passenger information. These predictions are transmitted electronically to signs at bus shelters and can even be accessible on the Internet or on home appliances such as clocks (http://www.enn...4692.asp). Additional ideas developed by the U.S. Federal Transit Administration (FTA) include making this information available via telephone, cable television, kiosks, and message signs located in shopping centers, restaurants, and other convenient locations. In terms of multi-modal transportation, arrival and departure times of other modes of transportation can actually be accessible in vehicles, making connections more reliable. The idea is that passengers have access at any given time and location to information on when these vehicles will arrive or depart. This is especially beneficial to the novice transit user with respect to general routes, shelters and schedules.

Another advancement that improves convenience and reliability of mass transit is automated stop announcement and passenger information within a vehicle. Talking Bus is a company promoting the use of these systems, which relieve operators from having to announce stops. This helps to keep the operator’s attention on the road and the surrounding environment, improving the safety of the passengers. This information system also provides a consistent environment within the vehicle in terms of accuracy and clarity of stops and various other announcements. The Talking Bus system automatically adjusts to varying noise levels within the vehicle (http://www.talkingbus...html). A consistent messaging system with accuracy and clarity provides reliability to passengers of varying ages and abilities.
Automated Fare Collection. An inconvenience that many potential mass transit users are faced with is handling of cash and coins for fares. The FTA is involved with implementing multi-modal fare payment. This idea eliminates cash and coins, and is even more convenient in that it implements use of only one card for many different forms of transportation. A city that has a rapid transit system in addition to other bus routes and transits can implement a one-card system to collect fares for all modes used. This has been made possible through advancements in electronic data processing and storage, magnetic recording technology, microcomputers, and data communication. These automated fare payment systems can also implement more sophisticated pricing with respect to distance traveled and time of day. Additionally, this electronic advancement improves security for passengers.

MATERIALS TECHNOLOGY AND MASS TRANSIT
The lighter, stronger, materials that are becoming available today as alternatives for vehicle structure also provide benefits for mass transit technology. The Chicago Transit Authority forecasts the use of advanced composite alloys for vehicle structure. This material is so light that it simulates a floating movement of the vehicle. These lightweight composite structures require lower power and lower-emission engines without sacrificing performance. Additionally, brake life is extended, tire wear is reduced, and preventative maintenance is reduced due to the inherently corrosion-resistant material. The same durable, lighter-weight material that can be used for the vehicle can also be used for support girders and structures (http://www.enn...6761.asp). The result is aesthetically pleasing structures that take up less space. All of these benefits individually reduce operating costs of mass transit.

One specific composite material becoming available on the market for mass transit is glass-fiber reinforced vinyl-ester resin laminate. This is produced using SCRIMP (Seeman Composite Resin Infusion Molding Process) technology. SCRIMP is a patented resin-transfer technique performed under high vacuum in which the product is a completely compacted fiber with undetectable void content according to testing by the American Society for Testing Materials (ASTM). This technology enables the production of large, one-piece composite structures with extremely high fiber content and high consistency resulting in exceptional tensile and impact properties and high strength-to-weight ratios (http://www.transit...htm). The benefits of these types of composites include extreme weight reduction, simplicity of repair, and complete resistance to corrosion, all of which dramatically reduce cost, and lead to increased passenger use.

The FTA suggests high strength steels, carbon fiber (graphite) composites, aluminum, and various metallic and non-metallic honey comb sandwiches as vehicle structure materials. These materials also provide equivalent strength but have less weight, giving them a desirably high strength-to-weight ratio. The use of these lighter weight materials will result in an increase in fuel economy, a decrease in power and size of propulsion plants, and a decrease in exhaust emissions. In conserving power and fuel, the cost of travel drastically decreases, making mass transit more desirable. In decreasing fuel emissions, mass transit provides a more environmentally friendly approach to transportation.

ALTERNATIVE ENERGY SOURCES
Perhaps the most significant change in mass transit, as with other forms of ground transportation, is coming from the rapid improvement in alternative forms of energy as we continue to find improvements to and substitutes for petroleum-based energy. Among the more promising alternatives for are electricity, natural gas, fuel cells, biodiesel and alcohols.

Electricity. A zero-emission alternative to petroleum that has been available for many years is electricity, the common energy source for subways and light rail systems, and an option currently used in many cities with electric-cable buses. Recent technology, however, uses electricity independently of a fixed electric cable by using fuel cells or battery storage. The big appeal of electricity is having a clean and quiet operating system. Some cities and countries have begun to use electric buses, but their future is uncertain. Whereas electric batteries may be feasible for privately owned cars, their near-term use in developing countries is unlikely because of the high costs.

Natural gas. Natural gas is a mixture of hydrocarbons, mainly methane (CH 4 ), produced either from gas wells or together with crude oil production. Interest for natural gas as an alternative fuel arises from its clean burning qualities, its wide resource base, and its commercial availability to users. It must be stored on board vehicles as either compressed natural gas (CNG) or liquefied natural gas (LNG). Natural gas is widely distributed throughout the United States and other countries through extensive pipeline systems that consist of long-distance transmission systems, followed by local distribution systems. Natural gas has numerous benefits in terms of economics, pollutants, greenhouse gases, safety, and general abundance.

Natural gas costs an average of 15 to 40 percent less than gasoline and diesel on an equivalent basis. It is the cleanest-burning alternative fuel and it reduces vehicle maintenance. Emissions of carbon monoxide are approximately 70 percent lower, non-methane organic gas emissions are 89 percent lower, and nitrogen oxide emissions are 87 percent lower. Per unit of energy, natural gas produces lower CO2 emissions per vehicle mile traveled. Although natural gas vehicles emit methane, another principal greenhouse gas, any slight increase in methane emissions would be more than offset by a substantial reduction in CO2 emissions. Natural gas vehicles are as safe as vehicles operating on traditional fuels such as gasoline. Many school transportation managers choose natural gas for their school buses because compressed natural gas dissipates into the atmosphere in the case of an accident.

Natural gas vehicles have an excellent safety record for two basic reasons — the structural integrity of the NGV fuel system and the physical qualities of natural gas as a fuel. The fuel on-board storage cylinders are much stronger than gasoline fuel tanks and are subjected to a number of stringent tests, such as heat and pressure extremes, gunfire, collisions and fires. Furthermore, the fuel systems are “sealed,” thereby preventing spills or evaporative losses.

Fuel Cells. While batteries store electricity that is generated from an outside source, fuel cells actually generate electricity on board the vehicle in a compact assembly. Fuel cells generate electricity for powering the vehicle from an electrochemical reaction between hydrogen and oxygen in controlled conditions. The only waste generated in this process is water vapor (Cannon, 1998). Oxygen is readily available in the atmosphere. Hydrogen, on the other hand, must be provided as fuel for the vehicle.

Researchers are currently evaluating two different ways of obtaining the hydrogen needed for fuel cell powered vehicles to create electricity. Hydrogen and methanol are both produced from natural gas. Hydrogen fuel cell vehicles seem to be simpler and more cost-efficient in the sense that the fuel is in its required form on board the vehicle, not requiring the vehicle to have on board the excess reforming factory. Whether used as a compressed gas or as a liquid, however, hydrogen’s energy density is very low compared to methanol’s and especially compared to gasoline’s. This low density requires very large, heavy tanks on board the vehicle - a feature not desirable for a compact, lightweight vehicle. Additionally, for hydrogen to be the fuel of choice for fuel cell powered automobiles, it would be necessary to create a whole new infrastructure for refueling stations (http://pubs.acs...html). Many researchers do agree, however, that using hydrogen as a fuel for mass transit applications such as large buses would be advantageous for two reasons: the necessity for a large fuel tank would be feasible in a large vehicle and there are benefits of refueling at a central location. Fuel cell buses are currently being tried in Chicago and in Ontario, Canada.

Methanol provides another option for generating hydrogen for fuel celled vehicles in which the hydrogen is extracted from methanol via on-board reformers. Methane is converted into methanol, a liquid fuel, and is pumped in a similar way to how gasoline is pumped. Methanol-powered vehicles carry on board a small chemical reforming factory that splits away four atoms of hydrogen from a single atom of carbon. The hydrogen can then be used in the fuel cell to generate electricity. The downfall is that converting the methane forms about 80-85% as much carbon dioxide as gasoline during combustion (Weisbrod, 1999). This is not a zero-emission vehicle, but it releases pollutants at lower levels than the internal combustion engine and, therefore, has smaller environmental impacts than existing vehicles. The major advantage of methanol over hydrogen fuel is that the infrastructure is already built to accommodate methane, and methanol’s higher density allows for a smaller, on-board storage tank. The chemical-reforming factory, however, involves a great deal of weight for a small vehicle. Again, this alternative fuel would not pose as many problems and would work best with mass transit vehicles.
Biodiesel (mono alkyl esters). This cleaner-burning diesel fuel is made from natural sources such as vegetable oils and animal fats. It operates as a substitute for petroleum diesel in combustion-ignition engines with no engine modifications required. Emission properties are better than for conventional diesel. Biodiesel in a conventional diesel engine gives a substantial reduction of unburned hydrocarbons, carbon monoxide, and particulate matter. It decreases the solid carbon fraction of particulate matter and eliminates the sulfate fraction, while the soluble fraction stays the same or is increased. Much of the current interest in biodiesel production comes from soybean producers faced with an excess of production capacity, product surpluses, and declining prices. Methyl soyate, or SoyDiesel, made by reacting methanol with soybean oil, is the main form of biodiesel in the United States. With Government incentives, biodiesel could probably be used as a fuel in bus fleets and heavy-duty trucks (primarily in blends with fossil diesel at the 20 percent level).

Ethanol and Methanol. These clear, colorless liquids are alcohols made primarily from natural gas, but they can also be made from wood, coal, petroleum and biomass. Ethanol and methanol would most likely be shipped from import terminals or production facilities by barge, rail, or truck. Although the alcohols are liquids at ambient temperatures and atmospheric pressures, they are not easily moved through the existing petroleum network. Two higher blends of ethanol, E-85 and E-95 are being explored as alternative fuels in demonstration programs. Ethanol is already being used in gasohol, but ethanol used in gasohol is not considered an alternative fuel. Since E-85 is not widely used, and E-95 is only used in demonstration projects, outlets for these alternative fuels are not available. Methanol can be made into an ether, MTBE, which can be blended with gasoline to enhance octane and to create oxygenated gasoline at a user cost not much different from diesel fuel. If ethanol and methanol become usable as an alternative fuel, they will reduce vehicle emissions of pollutants and greenhouse gases.

EXPERIENCES WITH ALTERNATIVE FUELS FOR MASS TRANSIT
A comprehensive literature review on alternative fuels for mass transit shows a variety of approaches to new energy technologies for buses (Lynch, et al. 1999). An array of examples gives evidence of increasing attention to urban transportation and efforts toward more sustainable cities. In Curitiba, Brazil transportation and land use plans have been coordinated in support of efficient public bus systems. Two out of three trips within Curitiba are by bus although there is one car for every three people (http://www.enn. com/enn-news-archive, 1999). In the United states, a change of transportation technology in Chattanooga, Tennessee has helped to change the city from one of America’s most polluted to one of its most livable cities in less than 30 years. This was partly accomplished by a transit switch that included 15 battery-electric buses (Dugan, 1994).

Perhaps the most important source of information on the development of alternative fuels can be found in the U.S. Department of Energy’s Alternative Fuels Data Center (AFDC) which maintains an “Alternative Fuels Data Base” (http://www.afdc.doe.gov/amfa). This website provides a comprehensive source of information on alternative fuels. The AFDC collects operating information from vehicles running on alternative fuels, analyzes the data, and makes them available to the public. Of particular interest to this review is the Alternative Fuels Transit Bus Program, which was designed to provide a comprehensive study of alternative fuels that are being used by the American transit bus industry. The study looked at the reliability, fuel economy, capital and operating costs, and emissions of vehicles running on the various alternative fuels. Alternative fuels used in the program include methanol, ethanol-plus, liquid natural gas (LNG), and compressed natural gas (CNG). The comparative results of the operating characteristics are available from AFDC.

Another important source of Internet information on alternative fuels is Calstart (http://www.calstart. org) which has extensive information and links to other sources of information for the transportation industry (Calstart, 1996). Calstart claims to be “your best information source for advanced transportation technologies.” Much of Calstart’s information is technology-based. The only transit system reviewed is a four-year study of the Santa Barbara Metropolitan Transit District’s use of battery-electric transit vehicles. These vehicles have proven to be quite successful, with a ten-fold increase in ridership during its first year of operation and an increase in the fleet of battery-electric vehicles.

Insight into operation of alternative fuel buses is provided in a report of alternative fuels used by buses (CUTR, 1995). The report analyzed air quality data and identified the most pressing air quality problems that could be addressed by an alternative fuels program in Tampa, Florida. It also analyzed alternative fuel vehicles in transit and evaluated advantages and disadvantages of each of eight fuel types:

• Reformulated gasoline and diesel fuel (RFG, RFD)
• Propane - the main ingredient in liquefied petroleum gas (LPG)
• Compressed natural gas (CNG)
• Liquefied natural gas
• Ethanol
• Methanol
• Biodiesel
• Electric vehicles (including EVs with solar recharging stations)

A general assessment and detailed analysis was performed for each of these fuels in all types of vehicles in the bus fleet, particularly full-size buses. Two of the liquid/gas fuels, CNG and LNG, showed the highest potential for successful conversion. The recommended “alternative fuels implementation plan” identifies CNG as the primary fuel, with electricity and diesel as the secondary fuel for routes with short range and low load factors, or that require a spare CNG bus to resume operations during refueling. The report provides many tables and figures with information from the study.
The first American urban bus fleet to convert 100 percent to CNG fuel is the 40-bus fleet of Thousand Palms, California’s Sunline Transit Agency, which rolled into service in May 1994. A report by Daly and Cromwell (1997) reviews the CNG fleet performance, including cost savings, environmental impact, safety record, and economic impact. The city’s decision to switch to CNG started with a visit to the Toronto transit agency, which had purchased 35 CNG buses. Sunline’s initial research showed CNG to be the most viable fuel because it is abundantly available, politically stable and CNG technology is available and working.

The choice of battery-electric buses has met with some favor as reported in a study of the feasibility of electric bus operations in Austin, Texas (Fowler and Euritt, 1995). Their study attempted to determine the technical and economic feasibility of electric bus operations using Austin’s Capital Metropolitan Transportation Authority as a case study. Their findings indicate that battery-electric buses are feasible in low-mileage circulator routes in the central business district, but they have a limited range and a substantially higher capital cost than other types of alternative fuel buses.
“AFDC Update” (1997), a newsletter published by the Alternative Fuels Data Center, states that alternative fuels bus data is available from a study by the National Renewable Energy Lab and Battelle Columbus Lab for eight American cities. Data were gathered on operations, maintenance, emissions, safety incidents, and bus duty cycle for the following fuels:

• Liquefied natural gas (LNG)
• Compressed natural gas (CNG)
• Ethanol (E93: 93%ethanol, 5% methanol, 2% kerosene)
• Propane
• Biodiesel (20% blend)

A report from the Battelle study, “Final Alternative Fuel Transit Bus Evaluation Results” (Chandler, et al., 1996) provides more detail. Under a program sponsored by the U.S. Department of Energy, Battelle served as the interface between West Virginia University, the University of Missouri - Columbia, the National Renewable Energy Laboratory (NREL), and the following eight participating transit agencies:
Houston Metro
Houston 15 buses*
Tri-Met  Portland, OR 13
Metro-Dade Transit Authority Miami 30
Pierce Transit Tacoma, WA 10
GP Transit Peoria, IL 8
Metropolitan Council Transit Operations Minneapolis/St. Paul 15
Triboro Coach Company New York 10
Bi-State Development Agency St. Louis 10
Includes both alternative diesel buses

The individual reports as well as the final evaluation report can be found on the Internet at http://www.afdc.doe.gov
Program results were grouped into reliability, fuel economy, bus operating costs, capital costs, and emissions testing. A number of tables and charts show the results in these categories. Among the more interesting conclusions and lessons reported:

Transit buses represent one of the best potential applications for alternative fuels because most transit buses are run from a central location (and fueling location) and the federal government contributes a significant portion of the cost of capital purchases (vehicles and facilities).... The results of this program show that alternative fuels are competing well with diesels in many areas.
• The Tacoma site has clearly shown that the reliability of alternative fuels was equal to diesel...
• Operating costs of the buses consisted mostly of costs for fuel (not including costs for driver labor)
• Operating costs were lowest for the CNG buses and highest for alcohol and biodiesel blend buses.
• Capital costs (including facility conversions) were inverse to operating costs.... At the present time, no alternative fuel combines low operating cost with a low up-front capital cost.
• Emission testing results of natural gas and alcohol buses show that alternative fuel technologies have the potential to significantly lower PM and NOx emissions as compared with diesel. With natural gas, PM emissions were virtually eliminated....”

SUMMARY AND CONCLUSIONS
As urban mass transit technology continues to improve, more vehicles will be powered by alternative means in the search for more efficient energy use, cleaner air, and quieter operations. They will use materials that are more advanced and have telecommunication and operating systems that will make them more appealing to urban users.

Urban mass transit in the developing world offers opportunities for ensuring the use of sustainable urbanization patterns. One of the essential elements is providing an urban transportation system that satisfies the needs of the public and stems the desire for private automobiles. Modern technology applied to mass transit provides endless possibilities for systems that are more user-friendly and environmentally friendly. All of mass transit technology’s possibilities have not been presented in the limited scope of this paper. Instead, the more popular and accepted ideas have been mentioned and analyzed. In terms of improved communications technology, individual vehicles may now be tracked via satellite, providing real-time arrival and departure information for passengers through public messaging boards and the Internet. Additionally, automated systems for vehicles and fare collection may be implemented for more consistent, simplistic service. The alternatives for fueling vehicles are also improving and growing rapidly, suggesting eventual abandonment of the emission-abundant internal combustion engine. Moreover, considering the emerging alternatives for vehicle composite materials, the amount of fuel needed to move these high strength-to-weight ratio vehicles will be further reduced. Working together, these technologies will provide preferred mass transit systems both to passengers and to the environment. By accounting for human health and the environment, mass transit design is leaning toward increasingly sustainable urban development.

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