research report

An Analysis of Travel Characteristics of Carless Households in California

Abstract

In spite of their substantial number in the U.S., our understanding of the travel behavior of households who do not own motor vehicles (labeled “carless” herein) is sketchy. The goal of this paper is to start filling this gap for California. We perform parametric and non-parametric tests to analyze trip data from the 2012 California Household Travel Survey (CHTS) after classifying carless households as voluntarily carless, involuntarily carless, or unclassifiable based on a CHTS question that inquires why a carless household does not own any motor vehicle. We find substantial differences between our different categories of carless households. Compared to their voluntarily carless peers, involuntarily carless households travel less frequently, their trips are longer and they take more time, partly because their environment is not as well adapted to their needs. They also walk/bike less, depend more on transit, and when they travel by motor vehicle, occupancy is typically higher. Their median travel time is longer, but remarkably, it is similar for voluntarily carless and motorized households. Overall, involuntarily carless households are less mobile, which may contribute to a more isolated lifestyle with a lower degree of well-being. Compared to motorized households, carless households rely a lot less on motor vehicles and much more on transit, walking, and biking. They also take less than half as many trips and their median trip distance is less than half as short. This study is a first step toward better understanding the transportation patterns of carless households.

Suggested Citation
Suman K. Mitra and Jean-Daniel Saphores (2018) An Analysis of Travel Characteristics of Carless Households in California. Available at: 10.7922/G2W957DN.

conference paper

Performance characterization and call reliability diagnosis support for voice over LTE

Proceedings of the 21st annual international conference on mobile computing and networking - MobiCom '15

Publication Date

January 1, 2015

Author(s)

Yunhan Jack Jia, Qi Alfred Chen, Zhuoqing Morley Mao, Jie Hui, Kranthi Sontinei, Alex Yoon, Samson Kwong, Kevin Lau
Suggested Citation
Yunhan Jack Jia, Qi Alfred Chen, Zhuoqing Morley Mao, Jie Hui, Kranthi Sontinei, Alex Yoon, Samson Kwong and Kevin Lau (2015) “Performance characterization and call reliability diagnosis support for voice over LTE”, in Proceedings of the 21st annual international conference on mobile computing and networking - MobiCom '15. ACM Press, pp. 452–463. Available at: 10.1145/2789168.2790095.

conference paper

Emergence of private advanced traveler information system providers and their effect on traffic network performance

TRANSPORTATION NETWORK MODELING 2002: PLANNING AND ADMINISTRATION

Publication Date

January 1, 2002

Author(s)

Abstract

The emergence of supply-side competition in the advanced traveler information system (ATIS) industry and marketability of private ATIS service are examined. An architectural model in which the ATIS companies collect network information from their subscribers while providing them with real-time traffic information is described. A simulation study on competition and cooperation among multiple private and public information agencies follows. This study focuses on analyzing the interaction among information agencies and the effect of this interaction on traffic system performance.

Suggested Citation
JS Oh and R Jayakrishnan (2002) “Emergence of private advanced traveler information system providers and their effect on traffic network performance”, in TRANSPORTATION NETWORK MODELING 2002: PLANNING AND ADMINISTRATION. TRANSPORTATION RESEARCH BOARD NATL RESEARCH COUNCIL, pp. 167–177.

policy brief

An Activity-based Toolbox for Planning Applications

Abstract

An activity-based modeling toolbox was produced for planning
agencies to investigate the effects certain policies have on travel
demand.

Suggested Citation
Will Recker (2019) An Activity-based Toolbox for Planning Applications. Policy Brief. Institute of Transportation Studies, Irvine. Available at: https://dot.ca.gov/-/media/dot-media/programs/research-innovation-system-information/documents/research-results/task2642-rrs-5-19-a11y.pdf.

MS Thesis

A holistic analysis of energy and environmental impacts from hydrogen as an alternative fuel in 2050 / Peter Willette.

Publication Date

January 1, 2014

Author(s)

Abstract

The driving factors for pursuing alternative fuels stem from energy issues associated with fossil based sources. In particular, such sources are finite in quantity, foreign sourced, and directly emit both greenhouse gasses (GHGs) and criteria pollutants during their utilization. In California, the transportation sector is in the lead for the consumption of overall energy by sector, with passenger vehicles emitting the most GHGs out of the entire transportation sector. Motivated by the large body of legislation and the complex nature of the potential alternative fuel supply chains, the goal of this work is to examine hydrogen as an alternative transportation fuel. To this end, a computer model was developed that allows for the systematic selection of preferred hydrogen supply chains. The goals of this thesis are to: 1) Establish spatially and temporally resolved generation, distribution, dispensing, and utilization scenarios for fueling the hydrogen transportation sector based on a systematic selection technique, and 2) Quantify the environmental impacts, and energy requirements in comparison to the current supply of petroleum fuels. The modeling approach developed herein, the Hydrogen Fueling infrastructure tool (HFit), takes a global decision-making approach to the creation and evolution of a future hydrogen infrastructure. In order to exercise the HFit, several case studies were conducted with different decision-making datasets. The outputs allowed for the simulation and quantification of a future hydrogen economy within the state of California on a spatial and temporal basis.

Suggested Citation
Peter Willette (2014) A holistic analysis of energy and environmental impacts from hydrogen as an alternative fuel in 2050 / Peter Willette.. MS Thesis. University of California, Irvine. Available at: https://uci.primo.exlibrisgroup.com/permalink/01CDL_IRV_INST/17uq3m8/alma991002758959704701.

research report

Resilience and Validation of GNSS PNT Solutions

Publication Date

November 20, 2023

Author(s)

Todd E. Humphreys, Qi Alfred Chen, Umit Ozguner, Charles Toth

Abstract

Highly automated transportation systems rely on a steady stream of signals and information from external sources for localization, route planning, perception, and general situational awareness. This includes reliance on positioning, navigation, and timing (PNT) information: Location is essential autonomous navigation and planning; and accurate timing is a precondition for on-board sensor fusion, cooperative control, and management based on information from other vehicles or the infrastructure. It is crucial to identify schemes for GNSS signal authentication and resilience that are well-suited for highly autonomous vehicles (HAVs). HAVs require PVT sensing techniques that are resilient to unusual natural or accidental events and secure against deliberate attack.

Suggested Citation
Todd E. Humphreys, Qi Alfred Chen, Umit Ozguner and Charles Toth (2023) Resilience and Validation of GNSS PNT Solutions. Final Report. Available at: https://rosap.ntl.bts.gov/view/dot/72661.

conference paper

On the existence of stationary states in general road networks

21st international symposium on transportation and traffic theory

Publication Date

January 1, 2015

Author(s)

Abstract

Our daily driving experience and empirical observations suggest that traffic patterns in a road network are relatively stationary during peak periods. In numerous transportation network studies, there has been an implicit conjecture that stationary states exist in a network when origin demands, route choice proportions, and destination supplies are constant. In this study, we first rigorously formulate the conjecture within the framework of a network kinematic wave theory with an invariant junction model. After defining stationary states, we derive a system of algebraic equations in 3-tuples of stationary link flow-rates, demands, and supplies. We then introduce a new definition of junction critical demand levels based on effective demands and supplies. With a map in critical demand levels, we show that its fixed points and, therefore, stationary states exist with the help of Brouwer’s fixed point theorem. For two simple road networks, we show that the map is well-defined and can be used to solve stationary states with a brute-force method. Finally we summarize the study and present some future extensions and applications. (C) 2015 The Authors. Published by Elsevier B.V.

Suggested Citation
Wen-Long Jin (2015) “On the existence of stationary states in general road networks”, in . Kuwahara, M and Kita, H and Asakura, Y (ed.) 21st international symposium on transportation and traffic theory. ELSEVIER SCIENCE BV (Transportation research procedia), pp. 689–703. Available at: 10.1016/j.trpro.2015.06.036.

published journal article

Airport congestion when carriers have market power

American Economic Review

Publication Date

November 1, 2002

Author(s)

Abstract

This paper analyzes airport congestion when carriers are nonatomistic, showing how the results of the road-pricing literature are modified when the economic agents causing congestion have market power. The analysis shows that when an airport is dominated by a monopolist, congestion is fully internalized, yielding no role for congestion pricing under monopoly conditions. Under a Cournot oligopoly, however, carriers are shown to internalize only the congestion they impose on themselves. A toll that captures the uninternalized portion of congestion may then improve the allocation of traffic. The analysis is supported by some rudimentary empirical evidence.

Suggested Citation
Jan K Brueckner (2002) “Airport congestion when carriers have market power”, American Economic Review, 92(5), pp. 1357–1375. Available at: 10.1257/000282802762024548.