Motor Vehicle Fleet Research Articles

Urban mobility worldwide?how does it look today?

When Traffic in Towns1 was published in 1963, the UK motor-vehicle fleet was probably as large a proportion of the world fleet as it has ever been or has been since. While motorisation had proceeded apace in North America in the 1930s, it had not really taken off elsewhere. The UK was one of the first countries outside the US to see a rapid burgeoning in motor-vehicle ownership after the Second World War, with the number of cars growing by 280% and road traffic by 190% between 1938 and 1963. In 1963, the UK road-vehicle fleet comprised almost 7% of the world total. Today it is a little over 4%. It is not surprising, therefore, that we saw the urban traffic-congestion problem as something that was characteristically British. Today, urban traffic-congestion from motor vehicles is to be found in many countries and, severe as our problems can be, it is in cities such as Bangkok, Mexico City, Cairo and Delhi where the largest incidences of urban traffic-congestion are to be found. This paper looks at urban travel in different parts of the world to see how the problems of actual and incipient mass-motorisation considered in Traffic in Towns1 are manifesting themselves. It leans heavily on the work done in compiling the report Mobility 2001: World Mobility at the End of the Twentieth Century and its Sustainability2 for the World Business Council for Sustainable Development, produced by a team from the Massachusetts Institute of Technology (to which the author was the senior transport consultant) and Charles River Associates, but the arguments and conclusions here are the responsibility of the author alone.

Technical and policy options for reducing emissions from 2-stroke engine vehicles in Asia

Two-stroke engine vehicles constitute a major share of the motor vehicle fleet in Asian countries. In South Asia, these vehicles account for about 60% of the motor vehicle fleet and contribute significantly to air pollution, resulting in adverse health effects, particularly for urban dwellers. They are a major contributor to particulate matter (PM) and hydrocarbon emissions, besides visible smoke. PM emissions from a typical 2-stroke engine used in South Asia are an order of magnitude higher compared to a 4-stroke engine of equivalent size. Poor vehicle maintenance, misuse of lubricants, and adulteration of gasoline exacerbate emissions from these vehicles. Emissions from existing 2-stroke gasoline engines can be reduced by using the correct type and quantity of lubricant, improving vehicle maintenance, and improving the quality of gasoline. For new vehicles, emissions can be reduced by redesigning 2-stroke engines to decrease scavenging losses, and installing catalytic converters to reduce tailpipe emissions. Some of these measures can be achieved through regulation, while others require mass education of drivers, vehicle owners, regulators, and the public at large. Other technical options include replacing the 2-stroke engine by 4-stroke gasoline engine and switching to cleaner alternative fuels such as liquefied petroleum gas, compressed natural gas, and electricity. This paper discusses various technical and supporting policy options for reducing emissions from 2-stroke engines.

AN INTERNATIONAL COMPARATIVE PERSPECTIVE ON MOTORISATION IN URBAN CHINA: Problems and Prospects

During a period of economic reform, the People's Republic of China has emerged as an important market for multinational automobile manufacturers and a source of concern for “sustainable transport” advocates worried about the long-term sustainability of systems based on private automobiles and fossil fuels. Much of the growth in China's motor vehicle fleet and the negative consequences of that growth has been concentrated in China's large, economically dynamic coastal cities. Based on a large standardised 1995 database on urban transport, this paper compares characteristics of three of China's largest cities with cities around the world. This international comparative perspective suggests that in 1995, Chinese cities still had exceptionally high use of non-motorised and public transport modes. However, some characteristics of these cities indicated a high potential for extensive and rapid growth in private motor vehicles which could generate significant problems in the future. In particular, the relatively high population density and lack of reserved public transport routes suggested that the potential for highly concentrated negative impacts were in place, while the means of moving large numbers of people with lesser polluting modes of transport than the private motor vehicle were not in place. Finally, data on investment in public transport and freeways indicated that in the early 1990s the conditions were being created for rapid and continued motorisation. While in 1995 China's cities in some ways approximated a “sustainable transport” ideal, this is likely to have already changed substantially.

Cross road and mobile tunable infrared laser measurements of nitrous oxide emissions from motor vehicles

Context Abstract: Nitrous oxide (NO2) is a potent greenhouse gas whose atmospheric budget is poorly constrained. One known atmospheric source is the formation of N2O on three-way motor vehicle catalytic converters followed by emission with the exhaust. Previous estimates of the magnitude of this N2O source have varied widely. Two methods employing tunable infrared lasers to measure N2O/CO2 ratios from a large number of on-road motor vehicles have been developed. Both methods add support to lower estimates of N2O emissions from the US motor vehicle fleet, although significant uncertainty remains.Main Abstract: Two tunable infrared laser differential absorption spectroscopy (TILDAS) techniques have been used to measure the N2O emission levels of on-road motor vehicle exhausts. Cross road, open path laser measurements were used to assess N2O emissions from 1361 California catalyst equipped vehicles in November, 1996 yielding an emission ratio of (8.8±2.8)×10−5 N2O/CO2. A van mounted TILDAS sampling system making on-road N2O measurements in mixed traffic in June, 1998 in Manchester, New Hampshire yielded a mean N2O/CO2 ratio of (12.8±0.3)×10−5, based on correlated N2O and CO2 concentration peaks attributed to motor vehicle exhaust plumes. The correlation of N2O emissions with vehicle type, model year and NO emissions are presented for the California data set. It is found that the N2O emission distribution is highly skewed, with more than 50% of the emissions being contributed by 10% of the vehicles. Comparison of our results with those from four European tunnel studies reveals a wide range of derived N2O emission indices, with the most recent studies (including this study) finding lower values.

Motor Vehicle Fleet Emissions by OP-FTIR

Using open-path Fourier transform infrared spectroscopy (OP-FTIR) we have measured the variations in ambient concentrations of carbon monoxide (CO), carbon dioxide (CO2), and nitrous oxide (N2O) caused by emissions from motor vehicles at a high traffic site in the Denver metropolitan area. Comparison of the OP-FTIR data to average emissions results obtained from on-road exhaust analysis using individual vehicle remote sensing revealed reasonable agreement, with a CO emission ratio (CO/CO2) of 0.050 ± 0.004 (100 ± 8 g CO/kg fuel) from OP-FTIR and 0.059 (118 g CO/kg fuel) from the on-road measurements. We also report a N2O emission ratio of (1.87 ± 0.13) × 10-4 (0.59 ± 0.04 g N2O/kg fuel) from OP-FTIR and outline the potential of OP-FTIR for on-road measurements of several important exhaust components.

A statistical model for estimating oxides of nitrogen emissions from light duty motor vehicles

Motor vehicle emission rate models for predicting oxides of nitrogen (NO x) emissions are insensitive to vehicle modes of operation such as cruise, acceleration, deceleration, and idle, because they are based on average trip speed. Research has shown that NO x emissions are sensitive to engine load; hence, load-based variables need to be included in emissions models. Ongoing studies attempting to incorporate these `modal' variables have experienced difficulties with: (1) incomplete and/or non-representative data sets of emissions test data vis-a-vis the modal operating profiles of the tested vehicles; (2) lack of information for predicting on-road operating parameters of vehicles; and (3) non-representative vehicles recruited for emissions tests. The objective of this research was to develop a statistical model for predicting NO x emissions from light-duty gasoline motor vehicles. The primary end use of this model is forecasting, rather than explanation of the factors that affect NO x emissions, which brings to bear different requirements from the statistical model. The three challenges noted above are addressed by: (1) analyzing a data set of more than 13 000 hot-stabilized laboratory treadmill tests on 19 driving cycles (specific speed versus time testing conditions), and 114 variables describing vehicle, engine and test cycle characteristics; (2) making the models compatible with empirical data on how vehicles are being operated in-use; and (3) developing statistical weights to account for the differences in model year distributions between the emissions testing database and the current national on-road fleets. The NO x emissions model is estimated using ordinary least-squares regression techniques, with transformed response variable and regression weights. Tree regression is employed as a tool for mining relationships among variables in the data, with particular focus on identifying useful interactions among discrete variables. Details of the model development process are presented, as well as results for the final model showing the predicted emissions algorithm for the current motor vehicle fleet in Atlanta, GA metropolitan region.

Scaling of Infrared Remote Sensor Hydrocarbon Measurements for Motor Vehicle Emission Inventory Calculations

Infrared (IR) remote sensors calibrated with propane understate volatile organic compound (VOC) concentrations in vehicle exhaust by 30−70% when compared to flame ionization detectors (FID). The difference depends on VOC composition and arises because many organic compounds in vehicle exhaust absorb less IR radiation than propane on a per-carbon basis. This study demonstrates an approach for scaling infrared measurements to reflect more accurately total exhaust VOC emissions from on-road motor vehicle fleets. Infrared versus flame ionization detector response to individual VOC was measured in the laboratory for methyl tert-butyl ether and a range of alkanes, alkenes, and aromatics that are prominent in vehicle exhaust. Overall IR/FID response to real exhaust mixtures was calculated by summing the response contributions of all individual VOC constituents. Average IR/FID response factors were calculated for typical on-road vehicle fleets based on VOC speciation profiles measured in several U.S. roadway tunnels. Results indicate that hydrocarbon concentrations measured by remote sensors with 3.4 μm filters should be multiplied by a factor of 2.0 ± 0.1 for light-duty vehicles using either California or federal reformulated gasoline blends and by 2.2 ± 0.1 when conventional gasoline is used.

Activities implemented jointly and the use of fuel alcohol in Brazil for abating CO 2 emissions

A sustained economic growth with low environmental hazards is a major challenge for modern society. Abating CO 2 gas emissions together with the rational uses of energy from clean sources is recognized as a priority worldwide. In this connection, this paper focuses on the possibilities for stimulating and expanding the production of fuel alcohol from sugarcane and the generation of thermoelectricity from bagasse, in the context of Activities Implemented Jointly. A methodology for calculating the CO 2 abatement costs in different scenarios for the use of fuel alcohol and bagasse is presented. The base scenario is constructed starting from an estimate of the motor vehicle fleet run on gasoline and on fuel alcohol. It is assumed the decreasing of alcohol vehicle fleet, as it happens now, and a blend of gasoline with only 10% of anhydrous alcohol. So, it is calculated the consumption of gasoline and alcohol up to the time horizon at the year 2010, as well as the total fuel costs using different hypothesis for the oil price. The alcohol cost is taken as constant in dollars of 1994 and equal to its value just before the overvalorization of the exchange rate between the Brazilian currency (Real-R$) and the US$. It is assumed that this exchange rate will probably be changed in the next years. It is considered in the base scenario alternatives of electricity expansion using coal, fuel oil and natural gas. The carbon emissions and thermoelectricity generation are obtained in two scenarios for abating CO 2 emissions by alcohol vehicle fleet besides the use of a blend of gasoline and 22% alcohol, as well as by implementing electricity generation with sugar cane bagasse. It is calculated the planted area with sugar cane to meet the alcohol and bagasse demand in each scenario. The abatement costs in the different scenarios, taking as reference the base scenario, is calculated. The main conclusion is that the abatement cost decreases along the time and with the increase of CO 2 abatement, reaching a value lower than US$ 10 t −1 CO 2 in the year 2010.

Characteristics of Air Pollution Condition in Dhaka City

This paper attempts to make clear the characteristics of the magnitude and scope of automotive and factory pollutant emissions in Dhaka city-which are creating an environmental problem in the city. About 451 factories in this city discharge and dump hazardous waste with no regard for the resulting surface and ground water or air-pollution. Most of these factories are bereft of adequate emission treatment. In addition, the increasing traffic, inadequate urban transport infrastructure and services, and an aging and obsolete motor vehicle fleet are giving rise to high air pollution levels. About 86% of the total motor vehicles in this city emit black smoke above the International Standard of 65 HSU. Changing meteorological conditions, such as average wind velocities, wind direction and frequency of showers have influenced the pollutant concentration in the city's air. Without effective measures to control pollutant emissions, the city dwellers will be exposed to unhealthy and dangerous levels of air pollution from automobiles and factories.

Air pollution from motor vehicles: issues and options for Latin American countries

Latin America is among the most urbanized regions of the world with relatively high motorization levels compared with the rest of the developing world. The automotive air pollution problem in Latin America is essentially a metropolitan problem, resulting from rapid and uncontrolled urban growth, increasing traffic congestion, inadequate urban transport infrastructure and services, and an aging and obsolete motor vehicle fleet. The problem is exacerbated by the vulnerable and sensitive physical location of the urban centers in the region. The paper discusses the size of the population in Latin America at risk, the magnitude of health costs associated with elevated levels of air pollution and the contribution of motor vehicles to the problem. The regional motorization characteristics and trends are analyzed, including certain similarities with industrialized countries. As some Latin American countries directed attention towards automotive air pollution long before other developing countries, there is a large body of practical and innovative pollution control experience in Brazil, Chile and Mexico from which other countries in the region could benefit.

“Passing the Test” – Human Behavior and California’s Smog Check Program

We have analyzed data obtained from more than 11,000 vehicles inspected in California's random roadside surveys to assess the realworld characteristics of the in-use motor vehicle fleet and to test the effectiveness of California's inspection and maintenance (I/M) program. The low-idle emissions data from these surveys show that 10 percent of the fleet are responsible for about 60 percent of the exhaust hydrocarbons and also that 10 percent of the fleet (not necessarily the same vehicles) are responsible for about 60 percent of the carbon monoxide emissions. We also show that high emitters appear among all model years, and not just among old vehicles, as previously assumed. Old vehicles, on average, have higher idle emissions than new vehicles, but they contribute relatively little to the total idle emissions because there are so few on the road. We compare roadside survey results at I/M and non-l/M locations in California, and observe identical tampering and overall failure rates at the two types of loca...

The Southern Company Uses a Probability Model for Cost Justification of Oil Sample Analysis

One of the difficult decisions facing managers responsible for maintaining motor vehicle and construction equipment fleets is whether or not to implement oil analysis programs. We developed a simple probability model for the Southern Company which enables their maintenance managers to evaluate various maintenance strategies including options that incorporate oil sampling programs. The model has been used to determine optimum policies for five classes of equipment and to assess the sensitivity of these results to various changes in the model parameters.

The Role of Fleet Leasing in Motor Vehicle Fleet Plans of Business Firms

The Role of Fleet Leasing in Motor Vehicle Fleet Plans of Business Firms

The Military Looks at Traffic Safety

The Department of Defense faces a two-fold traffic safety problem. First, it is the owner of one of the world's largest motor vehicle fleets, with aggregate annual mileages totalling in the billions; second, it is the employer of millions of young men, 2,000 of whom die every year in traffic accidents. Vigorous safety campaigning on the part of the Department has resulted in an impressive reduction in the num ber of accidents involving government-owned vehicles. The campaign to reduce the number of off-duty accidents to service men, however, faces many obstacles. The armed forces are composed largely of young men in the age group most prone to accidents; the chances are increased still further by the fact that servicemen, usually located somewhere away from their homes, are very likely to want to drive long distances on holiday and week-end leaves. The ability of the services to combat acci dents is limited by their lack of control over the serviceman and his car when neither is on military property. Many tech niques, however, are used. A close liaison with the states per mits education of offenders; tests to weed the bad drivers from the good allow education for the poor risks even before they have become violators. Inspection of cars located on base, lectures, driving rodeos, and movies are all aspects of the cam paign which has earned high praise for the safety efforts of the Department.