Papers by Jean-Daniel Saphores
Transportation Research Part A, 2023
Electrification of trucking combined with connected technologies promise to cut the cost of freig... more Electrification of trucking combined with connected technologies promise to cut the cost of freight transportation, reduce its environmental footprint, and make roads safer. If electric trucks are powerful enough to cease behaving as moving bottlenecks, they could also increase the capacity of existing roads and reduce the demand for new road infrastructure, a consequence that has so far been understudied. To explore the potential speed changes of replacing conventional heavy-duty drayage trucks with electric and/or connected trucks, we performed microscopic traffic simulations on a network centered on I-710, the country's most important economic artery, between the San Pedro Bay Ports and downtown Los Angeles, in Southern California. In addition to a 2012 baseline, we analyzed twelve scenarios for the year 2035, characterized by three levels of road improvements and four types of heavy-duty port trucks (HDPT). Our results show that 1,000 hp electric/hydrogen trucks (eTs) can be a substitute for additional freeway lanes in busy freight corridors. While conventional HDPTs with CACC would only slightly increase network speeds, replacing conventional HDPTs with eTs and improving selected I-710 ramps should be sufficient to absorb the forecast increases in drayage demand for 2035 without adding a controversial lane to I-710. Our results highlight the importance of accounting for the impacts on speed of new vehicle technologies in infrastructure planning. They also suggest shifting funding from building new capacity to financing 1,000 hp connected electric trucks in freight corridors until the market for these vehicles has matured.
Transportation Research Board 92nd Annual MeetingTransportation Research Board, 2013
The construction of a public transit system in a large metropolitan area can relieve congestion, ... more The construction of a public transit system in a large metropolitan area can relieve congestion, enhance mobility, and improve air quality. In a well-functioning housing market, these benefits will be reflected in housing prices. In this paper, the authors analyze transactions of apartments with elevators from 2007 and 2009 in Kaohsiung (Taiwan’s second largest city) to capture the impact of the opening in 2008 of a brand new mass rapid transit (MRT) system. Data includes time on market information (TOM) so the authors combine a two stage least square model with a geographically weighted regression model to tackle the joint determination of price and TOM. Results show that the opening of the MRT had a statistically significant and positive impact on the value of apartments with elevators. Moreover, accounting for TOM has a negligible impact on the results, which suggests that this information may not be necessary to perform hedonic studies of the housing market.
Transportation Research Board 90th Annual MeetingTransportation Research Board, 2011
We analyze the impact of state and local incentives on household ownership of hybrid electric veh... more We analyze the impact of state and local incentives on household ownership of hybrid electric vehicles (HEVs) while accounting for their socio-economic characteristics. Our large dataset combines household data from the 2009 National Household Travel Survey (NHTS) with zip code-level retail gas prices and congestion data from the Texas Transportation Institute, as well as information about state and city incentives. These incentives include unrestricted HOV access, income tax credit, sales tax rebates, and city parking privileges. By contrast, studies published so far focused on just one or two incentives and/or they analyzed only their local impact. We find that unrestricted access to HOV lanes paired with a parking incentive or sales tax rebates/exemptions can effectively promote household ownership of HEVs; by contrast, state income tax credits do not appear to have a statistically significant impact. Moreover, our results indicate that households are more likely to purchase HEVs in areas where gasoline prices are higher, which suggests that increasing gasoline tax could effectively promote HEVs. Understanding the effectiveness of various government policies is important at a time when there is renewed interest in promoting HEVs to address our dependence on foreign oil, air pollution and global warming.
AGU Fall Meeting Abstracts, Dec 1, 2017
American Journal of Agricultural Economics, May 1, 2002
Models used for natural resources prices usually preclude the possibility of large changes (jumps... more Models used for natural resources prices usually preclude the possibility of large changes (jumps) resulting from discrete, unexpected events. To test for the presence of jumps and ARCH effects, we propose to use bounds and bootstrap test techniques, thus solving the unidentified nuisance parameter problem. We apply this approach to stumpage price time series from the Pacific Northwest and find evidence of jumps and ARCH effects. Using real options, we then develop a stopping model to assess the impact of neglecting jumps on the decision to harvest oldgrowth timber. Our numerical results show the importance of modeling jumps explicitly.
This paper presents a methodology for deriving the closed-form density of diffusions restricted t... more This paper presents a methodology for deriving the closed-form density of diffusions restricted to finite intervals with reflecting or absorbing barriers. Bounded diffusions are useful, for example, in finance, resource economics, or industrial organization. Results are derived for popular diffusions.
Journal of Transport Geography, 2022
The empirical impact of housing costs on commuting is still relatively poorly understood. This im... more The empirical impact of housing costs on commuting is still relatively poorly understood. This impact is especially salient in California given the state's notoriously high housing costs, which have forced many lower-and middle-class households to move inland in search of affordable housing at the cost of longer commutes. To investigate this linkage, we relied on Generalized Structural Equation Modeling and analyzed 2012 CHTS data for Los Angeles County-the most populous county in the U.S. Our model, which jointly explains commuting distance and time, accounts for residential self-selection and car use endogeneity, while controlling for household characteristics and land use around residences and workplaces. We find that households who can afford more expensive neighborhoods have shorter commute distances (-2.3% and-3.1% per additional $100k to median home values around workplaces and residences respectively). Job density, distance to the CBD, and land-use diversity around workplaces have a relatively greater impact on commuting than the corresponding variables around commuters' residences. Compared to non-Hispanics, Hispanic workers commute longer distances (+3.5%), and so do African American (+5.1%) and Asian (+2.0%) workers compared to Caucasians, while college educated workers have shorter (-2.6% to-3.6%) commutes. Furthermore, commuters in the top income brackets tend to have faster commutes than lower income workers. Finally, women's commutes are ~41% shorter than men's, possibly because they are balancing work with domestic responsibilities. Better understanding the determinants of commuting is critical to inform housing and transportation policy, improve the health of commuters, reduce air pollution, and achieve climate goals.
International Journal of Engineering Science, 1991
A mathematical treatment is presented for the torsional response of a rigid disc embedded in a se... more A mathematical treatment is presented for the torsional response of a rigid disc embedded in a semi-infinite elastic medium. By means of the theory of Hankel transforms, an exact formulation for the mixed boundary value problem is obtained in the form of dual integral equations. On reduction of the dual integral equations to a Fredholm integral equation of the second kind, solutions to the problem are computed. In addition to providing a unified view of past solutions for surface and infinite embedments, the present analysis reveals a severe boundary-layer phenomenon which is apt to be of relevance to inclusion problems in general. As illustrations, selected numerical results on the torque-rotation relationship, the stress and displacement fields, as well as the contact distribution are provided.
Environment, Land Use and Urban Policy.: David Banister, Kenneth Button and Peter Nijkamp, editors. (Environmental Analysis and Economic Policy Series, No. 2). Edward Elgar Publishing, Inc., Glensanda House, Montpellier Parade, Cheltenham, Glos GL50 1UA, United Kingdom, 1999. 608 pp. ISBN 1-85898... Transportation Research Part A Policy and Practice
Regional Science and Urban Economics, 2000
eScholarship provides open access, scholarly publishing services to the University of California ... more eScholarship provides open access, scholarly publishing services to the University of California and delivers a dynamic research platform to scholars worldwide.
Social Science Research Network, 2022
University of California Transportation Center, Oct 1, 2008
The San Pedro Bay Ports (SPBP) of Los Angeles and Long Beach in Southern California comprise one ... more The San Pedro Bay Ports (SPBP) of Los Angeles and Long Beach in Southern California comprise one of the largest container port complexes in the world. The SPBP contribute significantly to both regional and national economies in California, and the US, respectively. However, the ongoing growth and economic benefits of the SPBP are threatened by negative externalities associated with port operations, particularly increasing congestion and air pollution. The objective of this paper is to explore a new approach to estimating vehicle emission impacts of freight corridor operations related to the port area, particularly those associated with heavy duty diesel trucks. The approach involves use of a microscopic traffic simulation model to capture detailed vehicle trajectories and congestion effects (ultimately including the effects of Intelligent Transportation System strategies), emissions modeling, and modeling the spatial dispersion of pollutants in the corridor, to facilitate estimation of the health and environmental justice impacts of freight corridor operations. In this paper we focus on operation of the I-710 freeway in the Alameda Corridor, leading from the SPBP area for about 20 miles toward Los Angeles. In a parallel effort we are also studying rail operations in the same corridor. In the future both the rail and highway elements will be combined to form an integrated, overall assessment of air quality impacts in the corridor. In this paper, seven scenarios were evaluated in addition to the 2005 Base Scenario: replacement of the current fleet of port heavy duty diesel trucks with zero emission trucks (25%, 50%, and 100% of port trucks), elimination of port heavy duty diesel truck trips (25%, 50%, and 100% reductions) that would correspond to shifting more containers to other modes such as rail, and implementation of a truck restricted-lane on I-710 preventing trucks from using the left most lanes. The results show that fleet replacement with cleaner trucks yields the most emission reductions both quantitatively and spatially.
We propose a simple framework combining GIS and hedonic pricing to evaluate the impacts of local ... more We propose a simple framework combining GIS and hedonic pricing to evaluate the impacts of local industrial odors on surrounding residential houses for four Southern California cities. Using GIS, we flag houses located at various distances from car paint-shops and smelly polluters in the EPA's NET database. After accounting for heteroskedasticity through feasible GLS, we find a statistically significant reduction in house prices of up to 3.4%. These results have implications for the local control of industrial odors.
University of California Transportation Center, Mar 1, 2003
Transportation Research Part D, 2022
Diesel heavy-duty drayage trucks (HDDTs) serving the Ports of Los Angeles and Long Beach in South... more Diesel heavy-duty drayage trucks (HDDTs) serving the Ports of Los Angeles and Long Beach in Southern California are large contributors to regional air pollution, but cost remains an obstacle to replacing them with zero-emission HDDTs. To quantify the health and equity impacts of operating diesel HDDTs, we built a microscopic simulation model of a regional freeway network and quantified their emissions of PM2.5 (particulate matter with a diameter < 2.5 μm) and CO2 in 2012 and 2035, before estimating their contribution to selected health outcomes. We found that 483 premature deaths ($5.59 billion) and 15,468 asthma attacks could be attributed to HDDTs in 2012. Regulations and technological advances could shrink these impacts to 106 premature deaths ($1.31 billion) and 2,142 asthma attacks in 2035 (over 2/3 accruing to disadvantaged
communities) despite population growth and a 145 % jump in drayage traffic, but they still justify replacing diesel HDDTs with zero-emission HDDTs by 2035.
Springer eBooks, Jul 23, 2022
Earth System Analysis for SustainabilityEDITED BY HANS JOACHIM SCHELLHUBER, PAUL J. CRUTZEN, WILLIAM C. CLARK, MARTIN CLAUSEN AND HERMAN HELD xiv+454 pp., 51 figs., 23.5×15.5×2.7 cm, ISBN 0 262 19513 5 hardback, GB£ 24.95/US$ 38.00, Cambridge, MA, USA: The MIT Press, 2004 Environmental Conservation, Sep 1, 2005
Waste Management, Mar 1, 2013
Within the growing stockpile of electronic waste (e-waste), TVs are especially of concern in the ... more Within the growing stockpile of electronic waste (e-waste), TVs are especially of concern in the US because of their number (which is known imprecisely), their low recycling rate, and their material content: cathode ray tube televisions contain lead, and both rear projection and flat panel displays contain mercury, in addition to other potentially toxic materials. Based on a unique dataset from a 2010 survey, our count models show that pro-environmental behavior, age, education, household size, marital status, gender of the head of household, dwelling type, and geographic location are statistically significant variables for explaining the number of broken or obsolete (junk) TVs stored by US households. We also estimate that they are storing approximately 84.1 million junk TVs, which represents 40 pounds of scrap per household. Materials in each of these junk TVs are worth $21 on average at January 2012 materials prices, which sets an upper bound on collecting and recycling costs. This information should be helpful for developing more effective recycling strategies for TVs in the e-waste stream.
Journal of Regulatory Economics, Mar 1, 2004
This paper is part of the research program of the "Chaire en Économique de l'Énergie Électrique,"... more This paper is part of the research program of the "Chaire en Économique de l'Énergie Électrique," which has the following Canadian sponsors: Hydro-Québec, Ministère des Ressources Naturelles, Agence de l'Efficacité Énergétique, Ministère de l'Environnement, Université Laval and SSHRC. We thank the editor (Michael Crew) and two anonymous referees for very helpful comments. The authors are solely responsible for the views expressed here and for any remaining error.
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Papers by Jean-Daniel Saphores
communities) despite population growth and a 145 % jump in drayage traffic, but they still justify replacing diesel HDDTs with zero-emission HDDTs by 2035.
communities) despite population growth and a 145 % jump in drayage traffic, but they still justify replacing diesel HDDTs with zero-emission HDDTs by 2035.