research report

Life Cycle Assessment of Environmental and Economic Impacts of Deploying Alternative Urban Bus Powertrain Technologies in the South Coast Air Basin

Publication Date

June 1, 2019

Associated Project

Life Cycle Assessment of Environmental and Economic Impacts of Deploying Alternative Urban Bus Powertrain Technologies in the South Coast Air Basin

Author(s)

Analy Castillo, Brian Tarroja, Scott Samuelsen

Areas of Expertise

Freight, Logistics, & Supply Chain Public Transit, Shared Mobility, & Active Transportation Safety, Public Health, & Mobility Justice

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Abstract

To aid in addressing issues of air quality and greenhouse gas (GHG) emissions in the South Coast Air Basin, local transit agencies are considering a shift to battery electric buses (BEBs) and hydrogen fuel cell electric buses (FCEBs). Each of these options vary in their overall effectiveness in reducing different emission types over their life cycle, associated life cycle costs, ability to meet operational needs of transit agencies, and life cycle environmental footprint. This project carried out a life cycle-based analysis and comparison of the GHG emissions, criteria pollutant emissions, and other environmental externalities associated with BEBs and FCEBs, taking into account their ability to meet operational constraints of the Orange County Transportation Authority. From an environmental footprint perspective, this study found the following. First, both FCEBs and long-range BEBs have comparable impacts for global warming potential and particulate matter formation but when the FCEBs were fueled using renewable hydrogen. Second, using electricity from the current California grid mix to drive electrolysis to produce hydrogen for FCEBs produced only marginal benefits compared to current natural-gas fueled vehicles due to the low supply chain efficiency of this pathway. Third, the mining of precious metals is a major contributor to environmental footprint categories for both BEBs and FCEBs. Fourth, both FCEVs and long-range BEBs provide significant reductions in environmental footprint compared to conventional diesel and natural gas buses. From a cost perspective, this study found the following. First, with current-day cost inputs, FCEBs and BEBs have comparable total cost of ownership, but both have slightly higher costs than diesel and natural gas buses. Second, FCEBs have an equivalent total cost of ownership to BEBs when the electricity rate for charging is $0.24/kWh. Higher values render FCEBs as the cheaper option and lower values render BEBs as the cheaper option. Second, the total cost of ownership of these technologies is highly sensitive to electricity costs, and the rapid evolution of the electricity system has strong implications for the economic comparison between BEBs and FCEBs. Overall, this study finds that while both FCEBs and BEBs provide life-cycle environmental benefits, further cost reductions in electricity rates and initial purchase costs are needed to achieve total cost of ownership parity with conventional bus powertrains. With the rapid evolution of the electricity system and falling costs for renewable electricity resources, these cost reductions may occur in the near future.

Suggested Citation

Analy Castillo, Brian Tarroja and G. Scott Samuelsen (2019) Life Cycle Assessment of Environmental and Economic Impacts of Deploying Alternative Urban Bus Powertrain Technologies in the South Coast Air Basin. Available at: https://escholarship.org/uc/item/81f4361x (Accessed: October 11, 2023).

Related Publications

policy brief | Nov 2019

Electrified Buses Provide Life Cycle Environmental Benefits but Need Cost Reductions and Policy Support for Near-Term Adoption

working paper

A Simultaneous Model of Activity Participation and Trip Chain Generation by Households

Publication Date

July 1, 1997

Associated Project

UCTC: (1991) ISTEA version

Author(s)

Thomas Golob

Working Paper

UCI-ITS-WP-97-11, UCI-ITS-AS-WP-97-4, UCTC 439

Areas of Expertise

Travel Behavior, Land Use, & the Built Environment

View working paper

Abstract

A trip generation model has been developed using a time-use perspective, in which trips are generated in conjunction with out-of-home activities, and time spent traveling is another component of overall time use. The model jointly forecasts three sets of endogenous variables – (1) activity participation and (2) travel time (together making up total out-of home time use), and (3) trip generation — as a function of household characteristics and accessibility indices. It is estimated with data from the Portland, Oregon 1994 Activity and Travel Survey. Results show that the basic model, which has ten endogenous time use and trip generation variables and thirteen exogenous variables, fits well, and all postulated relationships are upheld. Test show that the basic model, which divides activities into work and nonwork, can be extended to a three-way breakdown of subsistence, discretionary and obligatory activities. The model can also capture the effects of in-home work on trip chaining and activity participation. We use the model to explore the effects on time use and trip chaining of GIS-based and zone-based accessibility indices.

Suggested Citation

Thomas F. Golob (1997) A Simultaneous Model of Activity Participation and Trip Chain Generation by Households. Working Paper UCI-ITS-WP-97-11, UCI-ITS-AS-WP-97-4, UCTC 439. Institute of Transportation Studies, Irvine. Available at: https://escholarship.org/uc/item/3ts6s6bp.

Related Publications

working paper | Oct 1993

Ameliorating Congestion by Income Redistribution

working paper | Jan 1997

Economics and Urban Transportation Policy in the United States

book/book chapter | Oct 1998

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working paper | Sep 1994

Population and Employment Densities: Structure and Change

Preprint Journal Article

Fleet Sizing for Robo-taxi Services: Comparing Novel and State-of-the-Art Scalable Modeling Approaches

Publication Date

July 19, 2022

Author(s)

Arash Ghaffar, Negin Shariat, Michael Hyland

View Preprint Journal Article

Abstract

Fleet sizing is one of the most important tactical planning problems facing transportation service providers; it directly and significantly impacts costs and customer service quality. This paper proposes a network flow-based formulation to model the robo-taxi, or automated mobility-on-demand (AMOD), service fleet sizing problem. The formulation is similar to the minimum cost flow problem formulation in a time-expanded network, except it includes a set of external flows as variables to model the fleet size decision, alongside empty repositioning vehicle movements. The study compares the network flow-based approach to the state-of-the-art deterministic AMOD fleet sizing modeling approach, which formulates the problem as a path covering problem that relies on constructing shareability graphs. Both approaches make several simplifying assumptions but they both admit exact solutions to large-scale problem instances. Using New York City taxi data, this paper compares the two approaches in terms of minimum fleet size (lower bound) estimates, empty vehicle miles traveled estimates, and computational complexity and performance. We conclude that the TDTP formulation has several advantages over the path cover approach including scalability, computational efficiency, conservation of vehicles during the analysis period, and empty vehicle miles/kilometers traveled forecasts.

Suggested Citation

Arash Ghaffar, Negin Shariat and Michael Hyland (2022) “Fleet Sizing for Robo-taxi Services: Comparing Novel and State-of-the-Art Scalable Modeling Approaches”. Rochester, NY: SSRN. Available at: 10.2139/ssrn.4168352.

research report

Dynamic Path-Based Equilibrium Assignment With Microscopic Traffic Simulation

Publication Date

April 1, 2005

Author(s)

Henry Liu, Lianyu Chu, Will Recker

Final Report

UCB-ITS-PRR-2005-13

Areas of Expertise

Infrastructure Delivery, Operations, & Resilience

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Abstract

This report summarizes research work conducted under TO4158 at the California ATMS Testbed of the Institute of Transportation Studies at the University of California, Irvine. Under this task order, the California ATMS testbed hosted two full-time PATH research postdocs (Henry Liu and Lianyu Chu) whose general responsibilities are focused on applications of ATMS in the Testbed environment. They are generally responsible for ensuring that the functional capabilities of the Testbed are designed, developed and maintained in a manner that complements and enhances the ATMS research objectives of the PATH program. Under the direction of PATH faculty researchers at UCI and the Testbed management team, they are generally responsible for software enhancements to the Laboratory “bench-top” system for modeling and evaluating ATMS, particularly with the microscopic simulation model Paramics. They also provided Caltrans the on-call support and technical guidance on various Caltrans micro-simulation projects related to the Paramics plugin modules developed at UCI. In addition to the general responsibilities outlined above, the PATH Researchers have specific research projects. The specific research project conducted under this task order is to develop a path-based equilibrium assignment model with micro-simulator Paramics. Since off-the-shlef Paramics can only do the link-based assignment, no path information during the traffic assignment process is stored nor provided. This will bring difficulties in the ATMS evaluation particularly related to the route diversion because partial or full path information is needed to conduct this type of evaluation with Paramics. To overcome this difficulty, a path-based assignment model is developed using Paramics Application Programming Interfaces (API) functions. The model comprises the advantages of the analytical traffic assignment model and the good properties of the simulation tools, which can represented the real world more properly. Some key techniques, route choice plug-in, turn penalty consideration and methods of successive average, and etc., were applied in the model. The Paramics V4 was selected as the demonstration simulation tool. A real grid network in Tucson, Arizona, was designed to test the performance of the model, and the results showed that the model converged to the user equilibrium as expected.

Suggested Citation

Henry Liu, Lianyu Chu and Will Recker (2005) Dynamic Path-Based Equilibrium Assignment With Microscopic Traffic Simulation. Final Report UCB-ITS-PRR-2005-13. Institute of Transportation Studies, Irvine, p. 17p. Available at: https://escholarship.org/uc/item/5cp244f4.

working paper

The Value of Time and Reliability: Measurement from a Value Pricing Experiment

Publication Date

September 1, 2003

Author(s)

Terence Lam, Kenneth Small

Working Paper

UCI-ITS-WP-00-3, UCTC 677

Areas of Expertise

Transportation Economics, Funding, & Finance Travel Behavior, Land Use, & the Built Environment

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Abstract

We measure values of time and reliability from 1998 data on actual behavior of commuters on State Route 91 in Orange County, California, where they choose between a free and a variably tolled route. For each route at each time of day and for each day of the week, the distribution of travel times cross different weeks is measured using loop detector data. The best-fitting models represent travel-time by its median and unreliability by the difference between the 90th percentile and the median. We present models of route choice both alone and combined with other choices, namely time of day, car occupancy, and installation of an electronic transponder. In our best model, containing all these choices except time of day, value of time (VOT) is $22.87 per hour, while value of reliability is $15.12 per hour for men and $31.91 for women. These values are 72%,48%, and 101%, respectively, of the average wage rate in our sample.

Suggested Citation

Terence C. Lam and Kenneth A. Small (2003) The Value of Time and Reliability: Measurement from a Value Pricing Experiment. Working Paper UCI-ITS-WP-00-3, UCTC 677. Institute of Transportation Studies, Irvine. Available at: https://escholarship.org/uc/item/47s4z7z5.

Phd Dissertation

High coverage point to point transit (HCPPT): A new design concept and simulation-evaluation of operational schemes.

Publication Date

March 6, 2003

Associated Project

Dissertation Grant Titled: High Coverage Point-to Point Transit HCPPT: A New Design Concept and Simulation-Evaluation of Operational Schemes For Future Technological Deployment

Author(s)

Cristian Cortes

Areas of Expertise

Public Transit, Shared Mobility, & Active Transportation

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Abstract

This dissertation research proposes the development and evaluation of a new concept for high-coverage point-to-point transit systems (HCPPT ). Overall, three major contributions can be identified as the core of this research: the proposed scheme design, the development of sophisticated routing rules that can be updated in real-time to implement and optimize the operation of such a design, and the implementation of a multi-purpose simulation platform in order to simulate and evaluate such a design under real network conditions. The design is based on Shuttle-style operations with a large number of deployed vehicles under a coordinated transit system that uses advanced information supply schemes with fast routing and optimization schemes. The system design is rather innovative and ensures that no more than one transfer is needed for the travelers, by using transfer hubs as well as reroutable and non-reroutable portions in the vehicles’ travel plans. It yields flexibility for demand-side benefits from options such as price incentives for time-bound “passenger-pooling” at the stops without destination constraints, by the users. A strict optimization formulation and solution for such a problem is computationally prohibitive in real-time. The design proposed in this dissertation is effectively geared towards a decomposed solution using detailed rules for achieving vehicle selection and route planning. If real-time update of probabilities based upon modeling the future dispatch decisions is included, then this scheme can be considered as a form of quasi-optimal predictive-adaptive control problem. Finally, a multi-purpose simulation platform is developed as part of this research in order to evaluate the performance of the system. The final simulations of HCPPT required point-to-point vehicle simulation, which is not possible with off-the-shelf simulators. The simulation framework uses a well-known microscopic traffic simulator that was significantly modified for demand-responsive vehicle movements and passenger tracking. A simulated case study in Orange County showed that with enough deployed vehicles, the system can be substantially better, even competitive with personal auto travel, compared to the often-unsuccessful traditional DRT systems and the existing fixed route public transit. Furthermore, HCPPT can be incrementally implemented by contracting out services to existing private operators.

Suggested Citation

Christian Cortes (2003) High coverage point to point transit (HCPPT): A new design concept and simulation-evaluation of operational schemes.. PhD Dissertation. UC Irvine. Available at: https://uci.primo.exlibrisgroup.com/permalink/01CDL_IRV_INST/17uq3m8/alma991035093193604701.

conference paper

Evaluation of feedback and feedforward coupling of synthetic aperture navigation with LTE signals

2019 IEEE 90th vehicular technology conference (VTC2019-Fall)

Publication Date

September 1, 2019

Author(s)

Ali Abdallah, Zaher Kassas

View conference paper

Suggested Citation

Ali A. Abdallah and Zaher M. Kassas (2019) “Evaluation of feedback and feedforward coupling of synthetic aperture navigation with LTE signals”, in 2019 IEEE 90th vehicular technology conference (VTC2019-Fall). IEEE. Available at: 10.1109/vtcfall.2019.8891521.

Phd Dissertation

A new framework for optimal freeway ramp control

Publication Date

June 30, 1995

Author(s)

Michael Zhang

Areas of Expertise

Infrastructure Delivery, Operations, & Resilience Intelligent Transportation Systems, Emerging Technologies, & Big Data

View Phd Dissertation

Suggested Citation

Michael Zhang (1995) A new framework for optimal freeway ramp control. PhD Dissertation. UC Irvine. Available at: https://uci.primo.exlibrisgroup.com/permalink/01CDL_IRV_INST/17uq3m8/alma991012139499704701.

published journal article

Hurricane threat in Florida: Examining household perceptions, beliefs, and actions

Environmental Hazards

Publication Date

January 1, 2017

Author(s)

Victoria Basolo, Laura J. Steinberg, Stephen Gant

View published journal article

Suggested Citation

Victoria Basolo, Laura J. Steinberg and Stephen Gant (2017) “Hurricane threat in Florida: Examining household perceptions, beliefs, and actions”, Environmental Hazards, 16(3), pp. 253–275. Available at: 10.1080/17477891.2016.1277968.

working paper

Geographic Scalability and Supply Chain Elasticity of a Structural Commodity Generation Model Using Public Data

Publication Date

October 1, 2012

Author(s)

Fatemeh Ranaiefar, Joseph Chow, Daniel Rodriguez-Roman, Pedro Camargo, Stephen Ritchie

Working Paper

UCI-ITS-WP-12-4

Areas of Expertise

Freight, Logistics, & Supply Chain

View working paper

Abstract

Freight forecasting models are data intensive and require many explanatory variables to be accurate. One problem, particularly in the United States, is that public data sources are mostly at highly aggregate geographic levels, while models with more disaggregate geographic levels are required for regional freight transportation planning. Second, supply chain effects are often ignored or modeled with economic input-output models which lack explanatory power. This study addresses these challenges by considering a structural equation modeling approach, which is not confined to a specific spatial structure as spatial regression models would be, and allows for correlations between commodities. A FAF-based structural commodity generation model is specified and estimated and shown to provide a better fit to the data than independent regression models for each commodity. Three features of the model are discussed: indirect effects, supply chain elasticity, and intrazonal supply-demand interactions. A validation of the geographic scalability of the model is conducted using data imputed with a goal programming method.

Suggested Citation

Fatemeh Ranaiefar, Joseph Y.J. Chow, Daniel Rodriguez-Roman, Pedro V. Camargo and Stephen G. Ritchie (2012) Geographic Scalability and Supply Chain Elasticity of a Structural Commodity Generation Model Using Public Data. Working Paper UCI-ITS-WP-12-4. Institute of Transportation Studies, Irvine. Available at: https://escholarship.org/uc/item/6hz8v1wx.