The Experts below are selected from a list of 59313 Experts worldwide ranked by ideXlab platform
Kara M Kockelman - One of the best experts on this subject based on the ideXlab platform.
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Forecasting Americans’ long-term adoption of connected and autonomous Vehicle technologies
Transportation Research Part A: Policy and Practice, 2017Co-Authors: Prateek Bansal, Kara M KockelmanAbstract:Automobile manufacturers, transportation researchers, and policymakers are interested in knowing the future of connected and autonomous Vehicles (CAVs). To this end, this study proposes a new simulation-based fleet evolution framework to forecast Americans’ long-term (year 2015–2045) adoption levels of CAV technologies under eight different scenarios based on 5% and 10% annual drops in technology prices; 0%, 5%, and 10% annual increments in Americans’ willingness to pay (WTP); and changes in government regulations (e.g., mandatory adoption of connectivity on new Vehicles). This simulation was calibrated with data obtained from a survey of 2167 Americans, regarding their preferences for CAV technologies (e.g., WTP) and their household's annual Vehicle transaction decisions. Long-term fleet evolution suggests that the privately held Light-Duty-Vehicle fleet will have 24.8% Level 4 AV penetration by 2045 if one assumes an annual 5% price drop and constant WTP values (from 2015 forward). This share jumps to 87.2% if one uses a 10% annual rate of decline in prices and a 10% annual rise in WTP values. Overall, simulations suggest that, without a rise in most people's WTP, or policies that promote or require technologies, or unusually rapid reductions in technology costs, it is unlikely that the U.S. Light-Duty Vehicle fleet's technology mix will be anywhere near homogeneous by the year 2045.
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evolution of the light duty Vehicle fleet anticipating adoption of plug in hybrid electric Vehicles and greenhouse gas emissions across the u s fleet
Transportation Research Record, 2011Co-Authors: Binny M Paul, Kara M Kockelman, Sashank MustiAbstract:With environmental degradation and energy security as serious concerns, it is important to anticipate how Vehicle ownership and usage patterns can change under different policies and contexts. This work ascertains the acquisition, disposal, and use patterns of personal Vehicles of a synthetic population over time and relies on microsimulation to anticipate fleet composition, usage, and greenhouse gas emissions under different settings. Twenty-five-year simulations predict the highest market share for plug-in hybrid electric Vehicles (PHEVs), hybrid electric Vehicles, and smart cars and the greatest reductions in carbon emissions under an increased gasoline price ($7/gal). Results under a "feebate" policy scenario (where fees apply to low-fuel-economy Vehicles, and rebates rise with fuel economies above a threshold) indicated a shift toward fuel-efficient Vehicles but with Vehicle miles traveled (VMT) rising, thanks to lower driving costs. Excepting the low PHEV price and feebate policy simulations, all ot...
David L Greene - One of the best experts on this subject based on the ideXlab platform.
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rebound 2007 analysis of u s light duty Vehicle travel statistics
Energy Policy, 2012Co-Authors: David L GreeneAbstract:U.S. national time series data on Vehicle travel by passenger cars and light trucks covering the period 1966–2007 are used to test for the existence, size and stability of the rebound effect for motor Vehicle fuel efficiency on Vehicle travel. The data show a statistically significant effect of gasoline price on Vehicle travel but do not support the existence of a direct impact of fuel efficiency on Vehicle travel. Additional tests indicate that fuel price effects have not been constant over time, although the hypothesis of symmetry with respect to price increases and decreases is not rejected. Small and Van Dender (2007) model of a declining rebound effect with income is tested and similar results are obtained.
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fuel economy and co2 emissions standards manufacturer pricing strategies and feebates
Transportation Research Board 91st Annual MeetingTransportation Research Board, 2012Co-Authors: David L Greene, David S. BunchAbstract:Corporate Average Fuel Economy (CAFE) standards for 2011 to 2016 and CO2 emissions standards for 2012 to 2016 have significantly increased the stringency of requirements for new Light-Duty Vehicle fuel efficiency. This study investigates the role of technology adoption and pricing strategies in meeting new standards, as well as the impact of feebate policies. The analysis is built upon a dynamic optimization model that simulates manufacturer decisions with the objective of maximizing social surplus while simultaneously considering consumer response and meeting CAFE and emissions standards. The results indicate that technology adoption plays a major role and that the provision of compliance flexibility and the availability of cost-effective advanced technologies help manufacturers reduce the need for pricing. Feebates, when implemented along with fuel economy and emissions standards, can bring additional fuel economy improvement and emissions reduction, but the benefit diminishes over years due to increasing stringency of the standards and feebates acting as a replacement of manufacturers’ pricing strategies.
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effect of fuel economy on automobile safety a reexamination
Transportation Research Record, 2005Co-Authors: Sanjana Ahmad, David L GreeneAbstract:Since 1975, the fuel economy of passenger cars and light trucks has been regulated by the corporate average fuel economy (CAFE) standards, established during the energy crises of the 1970s. Calls to increase fuel economy are usually met by a fierce debate on the effectiveness of the CAFE standards and their impact on highway safety. A seminal study of the link between CAFE and traffic fatalities was published by R. W. Crandall and J. D. Graham in 1989. They linked higher fuel economy levels to decreases in Vehicle weight and correlated the decline in new car weight with about a 20% increase in occupant fatalities. The time series available to them, 1947-1981, includes only the first 4 years of fuel economy regulation, but any statistical relationship estimated over such a short period is questionable. This paper reexamines the relationship between U.S. Light-Duty Vehicle fuel economy and highway fatalities from 1966 to 2002. Cointegration analysis reveals that the stationary linear relationships between the average fuel economy of passenger cars and light trucks and highway fatalities are negative: higher miles per gallon is significantly correlated with fewer fatalities. Log-log models are not stable and tend to produce statistically insignificant (negative) relationships between fuel economy and traffic fatalities. These results do not definitively establish a negative relationship between Light-Duty Vehicle fuel economy and highway fatalities; instead they demonstrate that national aggregate statistics cannot support the assertion that increased fuel economy has led to increased traffic fatalities.
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future potential of hybrid and diesel powertrains in the u s light duty Vehicle market
Industrial Organization, 2004Co-Authors: David L Greene, K G Duleep, Walter McmanusAbstract:Diesel and hybrid technologies each have the potential to increase Light-Duty Vehicle fuel economy by a third or more without loss of performance, yet these technologies have typically been excluded from technical assessments of fuel economy potential on the grounds that hybrids are too expensive and diesels cannot meet Tier 2 emissions standards. Recently, hybrid costs have come down and the few hybrid makes available are selling well. Diesels have made great strides in reducing particulate and nitrogen oxide emissions, and are likely though not certain to meet future standards. In light of these developments, this study takes a detailed look at the market potential of these two powertrain technologies and their possible impacts on Light-Duty Vehicle fuel economy. A nested multinomial logit model of Vehicle choice was calibrated to 2002 model year sales of 930 makes, models and engine- transmission configurations. Based on an assessment of the status and outlook for the two technologies, market shares were predicted for 2008, 2012 and beyond, assuming no additional increase in fuel economy standards or other new policy initiatives. Current tax incentives for hybrids are assumed to be phased out by 2008. Given announced and likely introductions by 2008, hybrids could capture 4-7% and diesels 2-4% of the Light-Duty market. Based on our best guesses for further introductions, these shares could increase to 10-15% for hybrids and 4- 7% for diesels by 2012. The resulting impacts on fleet average fuel economy would be about +2% in 2008 and +4% in 2012. If diesels and hybrids were widely available across Vehicle classes, makes, and models, they could capture 40% or more of the Light-Duty Vehicle market.
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future potential of hybrid and diesel powertrains in the u s light duty Vehicle market
Industrial Organization, 2004Co-Authors: David L Greene, K G Duleep, Walter McmanusAbstract:Diesel and hybrid technologies each have the potential to increase Light-Duty Vehicle fuel economy by a third or more without loss of performance, yet these technologies have typically been excluded from technical assessments of fuel economy potential on the grounds that hybrids are too expensive and diesels cannot meet Tier 2 emissions standards. Recently, hybrid costs have come down and the few hybrid makes available are selling well. Diesels have made great strides in reducing particulate and nitrogen oxide emissions, and are likely though not certain to meet future standards. In light of these developments, this study takes a detailed look at the market potential of these two powertrain technologies and their possible impacts on Light-Duty Vehicle fuel economy. A nested multinomial logit model of Vehicle choice was calibrated to 2002 model year sales of 930 makes, models and engine-transmission configurations. Based on an assessment of the status and outlook for the two technologies, market shares were predicted for 2008, 2012 and beyond, assuming no additional increase in fuel economy standards or other new policy initiatives. Current tax incentives for hybrids are assumed to be phased out by 2008. Given announced and likely introductions by 2008, hybrids could capture 4-7%more » and diesels 2-4% of the Light-Duty market. Based on our best guesses for further introductions, these shares could increase to 10-15% for hybrids and 4-7% for diesels by 2012. The resulting impacts on fleet average fuel economy would be about +2% in 2008 and +4% in 2012. If diesels and hybrids were widely available across Vehicle classes, makes, and models, they could capture 40% or more of the Light-Duty Vehicle market.« less
Seiichi Shiga - One of the best experts on this subject based on the ideXlab platform.
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Scenario analysis of lightweight and electric-drive Vehicle market penetration in the long-term and impact on the Light-Duty Vehicle fleet
Applied Energy, 2017Co-Authors: Juan C. González Palencia, Yuki Otsuka, Mikiya Araki, Seiichi ShigaAbstract:Electric-drive Vehicles, including hybrid electric Vehicles, plug-in hybrid electric Vehicles, battery electric Vehicles, fuel cell electric Vehicles and fuel cell hybrid electric Vehicles, are emerging as less polluting alternatives to internal combustion engine Vehicles. Therefore, it is important to assess their penetration in the Vehicle market in the future. A ‘two-step’ approach is used to estimate the optimum market penetration of lightweight and electric-drive Vehicles in the long-term and the impact on the Light-Duty Vehicle fleet, focusing on Japan. First, an optimization model is used to estimate the Vehicle market composition in 2050. Then, a Vehicle stock turnover model is used to estimate Light-Duty Vehicle fleet energy and material consumption, CO2 emissions and cost. Internal combustion engine Vehicles and hybrid electric Vehicles dominate in the Base scenario. Fuel cell hybrid electric Vehicles dominate when low cost is prioritized. Shift to battery electric Vehicles occurs when low CO2 emissions are prioritized. CO2 emissions are reduced 56.9% between 2012 and 2050 in the Base scenario. Lightweight mini-sized battery electric Vehicle diffusion has the largest CO2 emissions reductions, 87.3% compared to the 2050 baseline value; with the net cash flow peaking at 10.2 billion USD/year in 2035 and becoming negative after 2044.
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Energy, environmental and economic impact of mini-sized and zero-emission Vehicle diffusion on a Light-Duty Vehicle fleet
Applied Energy, 2016Co-Authors: Juan C. González Palencia, Mikiya Araki, Seiichi ShigaAbstract:Diffusion of battery electric Vehicles and fuel cell hybrid electric Vehicles can contribute to reduce passenger Light-Duty Vehicle fleet CO2emissions. However, barriers such as higher Vehicle capital cost and lack of electricity and hydrogen infrastructure prevent their deployment. A Vehicle stock turnover model was used to assess the impact of mini-sized and zero-emission Vehicle diffusion on passenger Light-Duty Vehicle fleet energy and material consumption, CO2emissions and cost, focusing on Japan. 2050 passenger Light-Duty Vehicle fleet energy consumption and tank-to-wheel CO2emissions in the base scenario are 48.7 and 51.9% lower than the 2012 values. Diffusion of mini-sized and battery electric Vehicles provides the largest energy consumption and CO2emissions reductions, 64.7, and 87.8% compared with the 2050 baseline values. Incremental cost of zero emission Vehicles is reduced through downsizing. The 2050 net cash flow for battery electric Vehicles diffusion is reduced from 15.9 to −16.7 billion USD/year if downsizing is applied; while in the case of fuel cell hybrid electric Vehicle diffusion, downsizing reduces the 2050 net cash flow from −12.5 to −47.8 billion USD/year. Thus, shifting to mini-sized zero emission Vehicles provides the quadruple benefit of reducing energy and material consumption, CO2emissions and cost.
Hesham A. Rakha - One of the best experts on this subject based on the ideXlab platform.
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modeling inclement weather impacts on traffic stream behavior
International journal of transportation science and technology, 2012Co-Authors: Hesham A. Rakha, Mazen Arafeh, Sangjun ParkAbstract:The research identifies the steady-state car-following model parameters within state-of-the-practice traffic simulation software that require calibration to reflect inclement weather and roadway conditions. The research then develops procedures for calibrating non-steady state car-following models to capture inclement weather impacts and applies the procedures to the INTEGRATION software on a sample network. The results demonstrate that the introduction of rain precipitation results in a 5% reduction in Light-Duty Vehicle speeds and a 3% reduction in heavy-duty Vehicle speeds. An increase in the rain intensity further reduces Light-Duty Vehicle and heavy-duty truck speeds resulting in a maximum reduction of 9.5% and 5.5% at the maximum rain intensity of 1.5 cm/h, respectively. The results also demonstrate that the impact of rain on traffic stream speed increases with the level of congestion and is more significant than speed differences attributed to various traffic operational improvements and thus shoul...
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Comparison of TRANSIMS’ Light Duty Vehicle Emissions with On-Road Emission Measurements
Journal of the Transportation Research Forum, 2010Co-Authors: Mansoureh Jeihani, Antoine G. Hobeika, Hanif D. Sherali, Hesham A. RakhaAbstract:The Transportation Analysis and Simulation System, TRANSIMS, contains a Vehicle emissions module that estimates tailpipe emissions for light and heavy-duty Vehicles and evaporative emissions for Light-Duty Vehicles. This paper describes and validates the TRANSIMS emission module and compares its emission estimates to on-road emission-measurements and other state-of-the-art emission models. The trend of the emissions estimated in thirteen different runs in each model are compared. The results indicate that the TRANSIMS model provides consistent trends of estimated carbon monoxide (CO) and hydrocarbons (HC) with field data trends and inconsistent trends of estimated nitrogen lxides (NOx). However, the magnitude of the emission estimated in TRANSIMS is closer to the field data than for other models.
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Vehicle Dynamics Model for Estimating Maximum Light Duty Vehicle Acceleration Levels
2009Co-Authors: Hesham A. Rakha, Matthew Snare, Francois DionAbstract:This paper presents and validates a Vehicle dynamics model for predicting maximum Light-Duty Vehicle accelerations for use within a microscopic traffic simulation environment. A database of unconstrained Vehicle acceleration data for 13 Light-Duty Vehicles and trucks is also constructed. Using field data, the proposed Vehicle dynamics model is validated and compared with a number of state-of-the-art Vehicle acceleration models, including the Searle model and the dual-regime, linear decay, and polynomial models. The proposed model is shown to be able to predict Vehicle behavior accurately with readily available input parameters and is flexible in estimating acceleration rates of both large and small Vehicles on varied types of terrain. Directions for further research are discussed.
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Vehicle DYNAMICS MODEL FOR ESTIMATING MAXIMUM Light-Duty Vehicle ACCELERATION LEVELS
Transportation Research Record, 2004Co-Authors: Hesham A. Rakha, Matthew Snare, Francois DionAbstract:A Vehicle dynamics model for predicting maximum Light-Duty Vehicle accelerations for use within a microscopic traffic simulation environment is presented and validated. The research also constructs a database of unconstrained Vehicle acceleration data for 13 Light-Duty Vehicles and trucks. With the use of the field data, the proposed Vehicle dynamics model is validated and compared with a number of state-of-the-art Vehicle acceleration models, including the Searle model and the dual-regime, linear decay, and polynomial models. The advantages of the proposed model include its ability to predict Vehicle behavior accurately with readily available input parameters and its flexibility in estimating acceleration rates of both large and small Vehicles on varied types of terrain.
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development of vt micro model for estimating hot stabilized light duty Vehicle and truck emissions
Transportation Research Part D-transport and Environment, 2004Co-Authors: Hesham A. Rakha, Kyoungho Ahn, Antonio A TraniAbstract:Abstract The paper applies a framework for developing microscopic emission models (VT-Micro model version 2.0) for assessing the environmental impacts of transportation projects. The original VT-Micro model was developed using chassis dynamometer data on nine light duty Vehicles. The VT-Micro model is expanded by including data from 60 light duty Vehicles and trucks. Statistical clustering techniques are applied to group Vehicles into homogenous categories. Specifically, classification and regression tree algorithms are utilized to classify the 60 Vehicles into 5 LDV and 2 LDT categories. In addition, the framework accounts for temporal lags between Vehicle operational variables and measured Vehicle emissions. The VT-Micro model is validated by comparing against laboratory measurements with prediction errors within 17%.
Heather L Maclean - One of the best experts on this subject based on the ideXlab platform.
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a dynamic fleet model of u s light duty Vehicle lightweighting and associated greenhouse gas emissions from 2016 to 2050
Environmental Science & Technology, 2019Co-Authors: Alexandre Milovanoff, Timothy J. Wallington, Hyung Chul Kim, Robert De Kleine, Daniel I. Posen, Heather L MacleanAbstract:Substituting conventional materials with lightweight materials is an effective way to reduce the life cycle greenhouse gas (GHG) emissions from Light-Duty Vehicles. However, estimated GHG emission ...
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A Dynamic Fleet Model of U.S Light-Duty Vehicle Lightweighting and Associated Greenhouse Gas Emissions from 2016 to 2050
2019Co-Authors: Alexandre Milovanoff, Timothy J. Wallington, Hyung Chul Kim, Robert De Kleine, Daniel I. Posen, Heather L MacleanAbstract:Substituting conventional materials with lightweight materials is an effective way to reduce the life cycle greenhouse gas (GHG) emissions from Light-Duty Vehicles. However, estimated GHG emission reductions of lightweighting depend on multiple factors including the Vehicle powertrain technology and efficiency, lightweight material employed, and end-of-life material recovery. We developed a fleet-based life cycle model to estimate the GHG emission changes due to lightweighting the U.S. Light-Duty fleet from 2016 to 2050, using either high strength steel or aluminum as the lightweight material. Our model estimates that implementation of an aggressive lightweighting scenario using aluminum reduces 2016 through 2050 cumulative life cycle GHG emissions from the fleet by 2.9 Gt CO2 eq (5.6%), and annual emissions in 2050 by 11%. Lightweighting has the greatest GHG emission reduction potential when implemented in the near-term, with two times more reduction per kilometer traveled if implemented in 2016 rather than in 2030. Delaying implementation by 15 years sacrifices 72% (2.1 Gt CO2 eq) of the cumulative GHG emission mitigation potential through 2050. Lightweighting is an effective solution that could provide important near-term GHG emission reductions especially during the next 10–20 years when the fleet is dominated by conventional powertrain Vehicles
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life cycle assessment of switchgrass and corn stover derived ethanol fueled automobiles
Environmental Science & Technology, 2005Co-Authors: Sabrina Spatari, Yimin Zhang, Heather L MacleanAbstract:Utilizing domestically produced cellulose-derived ethanol for the Light-Duty Vehicle fleet can potentially improve the environmental performance and sustainability of the transport and energy secto...
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life cycle assessment of switchgrass and corn stover derived ethanol fueled automobiles
Environmental Science & Technology, 2005Co-Authors: Sabrina Spatari, Yimin Zhang, Heather L MacleanAbstract:Utilizing domestically produced cellulose-derived ethanol for the Light-Duty Vehicle fleet can potentially improve the environmental performance and sustainability of the transport and energy sectors of the economy. A life cycle assessment model was developed to examine environmental implications of the production and use of ethanol in automobiles in Ontario, Canada. The results were compared to those of low-sulfur reformulated gasoline (RFG) in a functionally equivalent automobile. Two time frames were evaluated, one near-term (2010), which examines converting a dedicated energy crop (switchgrass) and an agricultural residue (corn stover) to ethanol; and one mid-term (2020), which assumes technological improvements in the switchgrass-derived ethanol life cycle. Near-term results show that, compared to a RFG automobile, life cycle greenhouse gas (GHG) emissions are 57% lower for an E85-fueled automobile derived from switchgrass and 65% lower for ethanol from corn stover, on a grams of CO2 equivalent per k...
