Showing papers in "Transportation Research Part D-transport and Environment in 2008"

The effects of route choice decisions on vehicle energy consumption and emissions

Abstract: Motorists typically select routes that minimize their travel time or generalized cost. This may entail traveling on longer but faster routes. This raises questions concerning whether traveling along a longer but faster route results in energy and/or air quality improvements. We investigate the impacts of route choice decisions on vehicle energy consumption and emission rates for different vehicle types using microscopic and macroscopic emission estimation tools. The results demonstrate that the faster highway route choice is not always the best from an environmental and energy consumption perspective. Specifically, significant improvements to energy and air quality can be achieved when motorists utilize a slower arterial route although they incur additional travel time. The study also demonstrates that macroscopic emission estimation tools (e.g., MOBILE6) can produce erroneous conclusions given that they ignore transient vehicle behavior along a route. The findings suggest that an emission- and energy-optimized traffic assignment can significantly improve emissions over the standard user equilibrium and system optimum assignment formulations. Finally, the study demonstrates that a small portion of the entire trip involves high engine-load conditions that produce significant increases in emissions; demonstrating that by minimizing high-emitting driving behavior, air quality can be improved significantly.

Characterization of vehicle driving patterns and development of driving cycles in Chinese cities

Abstract: Current driving cycles used in China are not able to accurately assess vehicle emissions due to their inadequate representation of real-world driving. We in this study analyzed the driving characteristics and developed the driving cycles in Chinese cities, then compared them to the European test cycle and the American Federal Test Procedure. Eleven cities were selected, covering different city sizes and geographical locations. Car chasing technique was employed in each city to collect speed-time data on freeways, arterials, and residential roads during traffic peak and non-peak periods. The data collected were adjusted by the traffic adjustment factors to reflect the overall traffic. Eleven driving parameters were used to characterize driving characteristics and develop driving cycles. The results indicate that city size, local road infrastructure, and driving behavior are the most important factors that lead to the significant differences in vehicle driving patterns among the cities. The comparison with the European and US cycles suggests that the emission factors produced from the European or US cycles-based tests could be significantly different than those from the driving cycles in China.

Climate change, enhanced greenhouse gas emissions and passenger transport – What can we do to make a difference?

Abstract: The transportation sector, led by the automobile, has been cited constantly as a major contributor through human intervention to climate change. Short of banning car use, the challenge remains one of understanding better what mix of actions might contribute in non-marginal ways to reducing the growth of greenhouse gas emissions and the absolute amount of CO2 produced by automobiles. This paper evaluates instruments aimed at a number of policy objectives linked to efficiency, sustainability and equity, focusing on social surplus gains in addition to cost effectiveness; but in particular the ability to reduce CO2. TRESIS, an integrated transport, land use and environmental strategy impact simulation program, is used to assess the influence on CO2 of a number of 'at source' and 'mitigation' instruments such as improvements in fuel efficiency, a carbon tax, variable user charges, and improvements in public transit. TRESIS is applied to the Sydney metropolitan area with instruments enacted in 2010 up to 2015.

Modelling of the fuel consumption for passenger cars regarding driving characteristics

Abstract: Road transportation is a major consumer of fuel in China. This paper explores the influence of driving patterns on fuel consumption using a portable emissions measurement system on ten passenger cars. It shows that vehicle fuel consumption per unit distance is optimum at speeds between 50 and 70 km/h, fuel consumption increasing significantly with acceleration. A VSP-based model was developed to calculate vehicle fuel consumption in this study, and produced good results compared to the measured data.

Cycling and walking: Explaining the spatial distribution of healthy modes of transportation in the United States

Abstract: This study analyzes the spatial distribution of healthy modes of transportation (cycling and walking commuting) at the county scale. Geographic information systems, negative binomial, and zero-inflated negative binomial regression techniques are used to test four types of geographic covariates: built, natural, socioeconomic, and civic environments. Descriptive, GIS, and regression results indicate that the expected count of cycling and walking commuters in a county increases significantly with unit changes in population density, natural amenities, education and wealth, and estimates of local civic concern. Expected counts decrease significantly by unit changes in pollution and the average distance traveled to work by a typical commuter.

A system dynamics model of CO2 mitigation in China's inter-city passenger transport

Abstract: Mitigation of greenhouse gas emissions from transportation has become increasingly important and challenging especially for developing countries. This paper takes the inter-city passenger transport in China as a case, and develops a system dynamics model for policy assessment and CO 2 mitigation potential analysis. It is found that the future demand for China’s inter-city passenger transport is expected to be large, with the turnover volume growing at a rate of 9% per annum and amounting to 6600 billion p-km in 2020. Major emissions reduction potential exists in inter-city passenger transport. In 2020, comparing to the case without any specific policies stressing mitigation, the reduction of CO 2 emissions ranges from 26% to 32% under those scenarios with policy controls. Sensitivity analysis reveals that the CO 2 mitigation will be best achieved by accelerating the development of railway network, together with slowing down the extension of highway network and imposing fuel taxes.

Source apportionment of VOCs at the petrol pumps in Kolkata, India; exposure of workers and assessment of associated health risk

Abstract: Ambient air quality at five busy petrol pumps in Kolkata, India is monitored for mono-aromatic hydrocarbons and carbonyls. Among the measured volatile organic compounds, toluene and formaldehyde were the most abundant. Source apportionment using chemical mass balance identified exhaust from roadway and refueling as the major sources. Monitoring of the service station workers revealed that the average exposure level for benzene and toluene were 3.9 and 5.5 fold higher than the ambient air. The integrated lifetime cancer risks due to benzene, ethylbenzene, formaldehyde and acetaldehyde and the overall hazard index due to chronic exposure to some hazardous volatile organic compounds are 1.48E−04 and 2.3 indicating the probability of cancer as well as chronic health effect on the workers exposed.

Quantifying the external costs of vehicle use: Evidence from America's top-selling light-duty models

Abstract: Vehicle externality costs include emissions of greenhouse and other gases (affecting global warming and human health), crash costs (imposed on crash partners), roadway congestion, and space consumption, among others. These five sources of external costs by vehicle make and model were estimated for the top-selling passenger cars and light-duty trucks in the US. Among these external costs, those associated with crashes and congestion are estimated to be the most practically significant. When crash costs are included, the worst offenders (in terms of highest external costs) were found to be pickups. If crash costs are removed from the comparisons, the worst offenders tend to be four pickups and a very large SUV: the Ford F-350 and F-250, Chevrolet Silverado 3500, Dodge Ram 3500, and Hummer H2, respectively. Regardless of how the costs are estimated, they are considerable in magnitude, and nearly on par with vehicle purchase prices.

Impacts of freeway high-occupancy vehicle lane configuration on vehicle emissions

Abstract: In California, high-occupancy vehicle (HOV) lanes on freeways have been implemented with two different configurations - continuous access HOV lanes, primarily used in Northern California, and limited access HOV lanes, primarily used in Southern California. Using a new emissions modeling methodology that integrates a microscopic traffic simulation model (PARAMICS) with a modal emissions model (CMEM), this study estimates and compares vehicle emissions contributed from these two types of HOV lane configurations. Under various scenarios with different levels of vehicle demand and percentage of HOVs in the traffic mix, it is found that the freeway with continuous access HOV lane consistently produce lower levels of pollutant emissions compared to the freeway with limited access HOV lane. This is primarily due to the highly concentrated weaving maneuvers that take place on the dedicated ingress/egress sections on the freeway with limited access HOV lane, which cause relatively higher frequency and magnitude of acceleration/deceleration events, resulting in higher emissions on these sections of the freeway.

Improving computerized routing and scheduling and vehicle telematics : A qualitative survey

Abstract: Previous work has shown that computerized routing and scheduling and vehicle telematics can play an important role in reducing fuel consumption and CO2 emissions of trucking companies. Here we use expert surveys to look at how these systems could be improved to positively impact on the CO2 efficiency and the utilization of trucks. The broad range of options was filtered on the basis of CO2 emissions mitigation targets as part of the decoupling of transport growth from energy use.

Locating battery exchange stations to serve tourism transport: A note

Abstract: Electric scooters can contribute to reducing the environmental impacts of tourism transport but they have only a limited range and their use is influenced by the location of recharging facilities. This study uses integer programming to optimize the location and number of battery exchange stations. Sensitivity analyses are performed on the service capacity on each site.

Better performance or lower fuel consumption: Technological development in the Swedish new car fleet 1975-2002

Abstract: Technology development may play a role in fuel reductions in transport, especially regarding automobiles. But these developments may be off-set by diverting technology gains into non-fuel saving vehicle features – ‘‘service attributes”. This paper estimates to what extent technological development, in the Swedish new car fleet, has resulted in lower fuel consumption or has improved service attributes. Changes between 1975 and 2002 are mapped through statistical analysis and modeling of a combination of sales statistics and vehicle attributes. About 35% of the effects of enhanced technology and design resulted in a net reduction in fuel consumption. The remaining 65% served to meet consumer demands for such things as increased passenger space and improved acceleration.

Assessment of private car stock and its environmental impacts in China from 2000 to 2020

Abstract: Economic growth and the rising demand for mobility in developing countries are leading to increased car ownership, with associated environmental problems. To develop appropriate policies to cope with this situation, reliable forecasts are needed of the stock of vehicles and its environmental impacts. This paper looks at the potential for car ownership increase in China’s 31 provinces and considers its likely effect on atmospheric pollution (notably, CO2, CH4, CO, NMVOC, NOx and SO2) up to 2020. The effects will continue to be spatially variable with a heavy concentration of car use and pollution in urban areas. At the meso level, the South and North Coast regions will have the highest levels of vehicle ownership and will be the most adversely affected by environmental damage.

A comparison of carbon dioxide emissions associated with motorised transport modes and cycling in Ireland

Abstract: Cycling is widely viewed as a transport mode with marginal environmental impacts. However, such a view fails to take account of such factors as the increase in carbon dioxide exhaled as a result of increased physical activity or the emission embodied in the manufacture of the bicycle. This paper presents estimates of emission factors for various forms of commuter transport in Ireland that allow comparison against emissions from cycling. When indirect energy is taken into account, the results presented here indicate that a cyclist commuting an equivalent distance to work releases an almost equal amount of carbon dioxide as that attributed to a passenger of an electrically propelled train at full occupancy during peak service times. Travel by bicycle is much less carbon intensive when compared to passengers travelling at off-peak times. Transport by car and sports utility vehicle is the most carbon intensive of the commuter modes of transport studied, however, travelling in a fully occupied car has an emission factor approaching that of off-peak bus transport.

Commuters’ Exposure to Particulate Matter and Carbon Monoxide in Hanoi, Vietnam

Abstract: This study provides estimates of personal exposures to particulate matter and carbon monoxide while traveling on four major roads in Hanoi, Vietnam. The effect of factors such as mode of transport (mobikes, buses, cars and walking), route, rush-hour, and air-conditioning on the exposure levels are examined. The mean value of particulate matter concentrations was found to be 455 μg m−3, with mobike riders being the most exposed and bus passengers being the least. The mean value of carbon monoxide concentrations was 15.7 ppm, with mobike riders being most exposed and pedestrians being the least exposed. Rush-hour levels for particulate matter and carbon monoxide are higher than during non-rush-hour periods.

The potential for premium-intermodal services to reduce freight CO2 emissions in the Quebec City–Windsor Corridor

Abstract: The Quebec City-Windsor corridor (the Corridor) is the busiest and most important trade and transportation corridor in Canada. The transportation sector is the second largest greenhouse gas (GHG) emission category in the country. This paper develops estimates of the potential for CO2 emission reductions in the freight transportation sector by estimating demand for premium-intermodal services between the main Corridor destinations. CO2 reductions are estimated on the basis of a stated-preference carrier-choice survey of shippers in the Corridor. Survey data were used to develop mode share models for five different categories of shipments between eighteen city-pairs. A railyard-catchment approach was taken to arrive at estimates of contestable intercity truck traffic using a subset of the Ontario Ministry of Transportations Commercial Vehicle Survey. CO2 emissions were based on current truck traffic estimates, and emissions factors obtained from MOBILE6.2C. The results show that premium-intermodal service has the potential to capture a significant share of traffic between the main Corridor destinations with potential CO2 emissions reductions in the range of 0.058 to 0.484 Mt a year.

Use of ecological footprinting to explore alternative transport policy scenarios in an Irish city-region

Abstract: The objective of this paper is to compare the ecological footprint for travel-commuting patterns for the residents of an Irish city-region, that is Limerick city-region, in 1996 and 2002. Scenario building, based on ecological footprint analysis, is used to estimate the impact of different policy choices for 2010. The optimal policy mix for sustainable travel is proposed and consists of a mix of reduced demand through travel demand measures, better spatial planning and technological improvements in fuel economy.

Transportation versus perishability in life cycle energy consumption: A case study of the temperature-controlled food product supply chain

Abstract: Moving goods from the point of production to markets involves energy use and can have adverse environmental effects. But from the supply chain management perspective, the control of the supply chain, with short time cycles between production and sale to customer, can benefit the environment by closely tailoring production to consumption, and by minimizing the amount of “perishability” in the chain. An energy consumption model is used to explore potential tradeoffs between these two competing tendencies and applied to temperature-controlled food products produced in agricultural regions in the US with mild climates and then distributed around the country using surface transportation. Although the use of rail can reduce life cycle energy consumption compared to truck, the increase in perishability of food products can undercut the energy savings, and in some circumstances, the use of inter-modal rail can be environmentally superior to carload freight for delivery.

Vehicle-type choice and neighbourhood characteristics: An empirical study of Hamilton, Canada

Abstract: The popularity of light-duty trucks has increased with important implications for air quality, traffic accidents and gasoline demand. While previous studies have shed light on vehicle-typechoice at the household level, little work has been done that examines the role of the built environment on these choices. This paper reports empirical findings on the relationship between vehicle-typechoice and neighbourhood characteristics within the Census Metropolitan Area of Hamilton in Canada. The analysis incorporates proximity and urban form measures derived from high-resolution spatial data and geographic information systems technology. Estimates from discrete choice models of households’ latest vehicle-typechoice suggest that preferences for less fuel-efficient vehicles are marginally affected by the diversity of land-uses at the place of residence, after controlling for travel to work attitudes and socio-demographic characteristics of individuals and households.

Environmental burden of disease due to transportation noise in Flanders (Belgium)

Abstract: Exposure to environmental noise due to transport affects public health. Cardiovascular diseases, sleep disturbance and annoyance are the most-reported harmful effects of noise exposure. Here, the burden of disease due to transportation noise in Flanders is quantified based on the disability adjusted life year methodology (DALY), combining the burden due to premature death and disability in a single index. The estimated number of DALYs due to transportation noise in Flanders in 2004 was 20,517, corresponding to 1.7% of the burden of disease in Flanders or 21.8% of the environmental burden of disease due to particular matter, ozone, carcinogenic air pollutants and noise. Nevertheless, the results must be interpreted carefully because of the rather large uncertainty range attributable to the variety in exposure level, the uncertainty of exposure-response functions and the choice of the severity weight.

Atmospheric particulate polycyclic aromatic hydrocarbons from road transport in southeast Brazil

Abstract: The Cubatao industrial complex of southeast Brazil is sited on a coastal strip bounded on the continental side by a mountainous scarp covered with tropical forest Four cities have developed around the complex The metropolitan region of Sao Paulo is located on a plateau above the scarp The combination of the region's topography, the industrial installations, and an intensely trafficked road network causes widespread atmospheric pollution In November 2004, measurements were made of the 16 polycyclic aromatic hydrocarbons designated as priority pollutants by the US Environmental Protection Agency, as well as of aerosol mass and ionic composition Use of characteristic concentration ratios for emission sources show that tailpipe emissions from diesel vehicles was the main source of the compounds This means that a shift from gasoline to ethanol as fuel in spark ignition engines will have only minor influence on atmospheric polycyclic aromatic hydrocarbon concentrations, despite very low emissions during ethanol combustion On the other hand, reduction in emissions associated with increasing use of biodiesel in compression ignition engine fuel mixtures could significantly reduce atmospheric concentrations

Using functional data analysis of diurnal ozone and NOx cycles to inform transportation emissions control

Abstract: Ozone pollution is caused by photochemical reactions of precursor volatile organic compounds and nitrogen oxides, of which transportation emissions are the single major source. Understanding the complexity of diurnal ozone processes and their relationships with precursors is thus critical for identifying optimal transportation emissions control strategies. This paper uses functional data analysis methods to model the dynamics of diurnal ozone and nitrogen oxides cycles, their interrelationships, and the multilevel spatio-temporal variations of ozone and nitrogen oxides measurements from Southern California. Functional data analysis accounts for the continuous nature of diurnal ozone/nitrogen oxides processes by converting discrete observations into functional diurnal curves. Results show important, but low-dimensional, spatio-temporal variations in diurnal ozone/nitrogen oxides cycles. Representative summer diurnal ozone profiles are constructed using functional clustering. Variability in hourly distribution of traffic activities and emissions is also discussed.

Deterioration of gasoline vehicle emissions and effectiveness of tune-up for high-polluted vehicles

Abstract: This study investigates the emissions using a chassis dynamometer for three types of passenger vehicles, including new vehicles, in-use vehicles, and highly polluted vehicles, based on the US federal test procedure (FTP-75) In-use high emitters, emit about 5–12 times more CO, NOx and HC Emission tests before and after repair and maintenance for high emitters indicated that tune-ups fail to reduce emissions because of deterioration of the three-way catalyst over time

Comparing air quality impacts of hydrogen and gasoline

Abstract: This paper uses a lifecycle approach to analyze potential air quality impacts of hydrogen and gasoline use in light duty vehicles. The analysis is conducted for scenarios in 2005 and 2025 in Sacramento, California for CO, NOx, VOC, and PM10. Three natural gas-based hydrogen supply pathways are analyzed: onsite hydrogen production via small-scale steam methane reforming (SMR), central large-scale hydrogen production via SMR with gaseous hydrogen pipeline delivery, and central hydrogen production via SMR with liquid hydrogen truck delivery. These are compared to gasoline pathways with current and advanced technologies, in terms of lifecycle air quality impacts. The centralized/pipeline hydrogen pathway reduces pollution the most, followed by the onsite hydrogen production pathway and the centralized hydrogen production with liquid hydrogen truck delivery. Gasoline pathway scenarios, even with advanced new gasoline vehicles, would lead to much higher ambient concentrations of pollutants than any of the hydrogen pathways, producing 273 times greater CO, 88 times greater VOC, 8 times greater PM10, and 3.5 times greater NOx concentrations than those caused by the centralized/pipeline hydrogen pathway.

The potential of liquid hydrogen for the future 'carbon-neutral' air transport system

Abstract: Global air traffic has grown considerably over the past two decades, contributing both to the globalization of the economy and overall welfare of society on the one hand and increasing emissions of greenhouse gases and local noise on the other. The latter has raised questions whether such a growing demand can continue to sustain, particularly regarding the long-term management of greenhouse gas emissions. This paper elaborates the potential of cryogenic aircraft using liquid hydrogen to achieve the ‘carbon-neutral’ air transport system. A model is developed to estimate the emissions of greenhouse gases following the gradual replacement of conventional by cryogenic aircraft according to different scenarios based on ‘what–if’ reasoning. This model is applied to the global air transport system.

Determinants of the severity of cruise vessel accidents

Abstract: This study investigates determinants of the property damage and injury severities of cruise vessel accidents. Detailed data of individual cruise vessel accidents for the period 1991-2001 that were investigated by the US Coast Guard were used to estimate cruise vessel accident property damage and injury severity equations. The estimation results suggest that cruise vessel damage cost per vessel gross ton is greater for: allision, collision, equipment-failure, explosion, fire, flooding, and grounding cruise vessel accidents than for other types of accidents and a human cause. The accident injury severity is greater for ocean cruise than for inland waterway and harbor/dinner cruise vessel accidents and a human cause. The unit damage cost for explosion accidents is greater than that for other types of accidents by $207 per vessel gross ton. If the accident is caused by a human, rather than an environmental or vessel factor, the probabilities of non-fatal and fatal injuries increase.

A simulation platform for computing energy consumption and emissions in transportation networks

Abstract: This work presents a methodology for studying the transportation and energy sectors in an integrated fashion. It is based on an object-oriented model that identifies and simulates transportation activity, both urban and interurban, to compute emissions and energy consumption. The approach is oriented towards strategic planning studies with a time horizon of ten years. A software code using Java technology is developed and applied to the main Chilean transportation systems. The software provides a basis for studying the effects of transportation on the environment. This methodology should be capable of predicting the impact due to the future implementation of technological improvements and policies at a country-wide level.

Simulated pedestrian travel and exposure to vehicle emissions

Abstract: This paper analyses pedestrian exposure to vehicle emissions and the role played by signal timings A complex network is coded in a micro-simulation model that allows tracking of vehicle and pedestrian movements and is linked to an emissions data base The effects of these emissions on the pedestrian paths and crossings are then estimated using an air dispersion model The suitability of various traffic signal plans and how they impact pedestrian exposure to CO and PM emissions is discussed

Contributions of roadside vehicle emissions to general air quality in Hong Kong

Abstract: Data for 7-year from three roadside, three urban background, and one rural monitoring stations are employed to look at the contribution of roadside vehicle emissions to the general air quality in central Hong Kong. It is found that within the urban core of Hong Kong, variations in concentrations of various gaseous pollutants are heavily influenced by variations in local traffic volume. The daily patterns of NO2, NOx, and particulates concentrations at roadside and background stations are similar while no common daily concentration pattern of SO2 can be found. Concentration at nearby roadside and background stations are closely correlated for all pollutants investigated. Daily variations of NO2, NOx, and particulates concentrations at roadside and urban background stations follow the traffic pattern of the area closely. Similarities exist between traffic volume and SO2 concentration, but they are less clear. For each of the pollutants, traffic volume and concentration in the urban background are positively correlated.

Source apportionment of suspended particulate matters in a clean area of Delhi: A note

Abstract: Source apportionment of suspended particulate matters was carried out at Jawaharlal Nehru University, an extremely clean location of Delhi, using chemical mass balance receptor model. The results reveal that diesel vehicles are the major contributors followed by the industrial source. Paved road dust, gasoline vehicles and solid waste contribute 10.2%, 6.2% and 5.8%, respectively. The contribution of soil and crustal dust was minimal. The contributions of most of the sources are generally variable, except the contribution of diesel vehicles.