research report

The personal travel assistant (PTA): Measuring the dynamics of human travel behavior

Abstract

A simple, continuously collected GPS sequence was investigated to determine whether it can be used to accurately measure human behavior. Hybrid Dynamic Mixed Network (HDMN) modeling techniques were applied to learn behaviors given an extended GPS data stream. A key design decision behind the proposed architecture was to use an Enterprise Service Bus (ESB) to provide a communication infrastructure among various components of the application. Personal Travel Assistants running on mobile devices like cell phones could help travelers change their travel plans when routes are affected by crashes or natural disasters.

Suggested Citation
Will Recker, James E. Marca, Craig Rindt and R. Dechter (2010) The personal travel assistant (PTA): Measuring the dynamics of human travel behavior. University of California Transportation Center, p. 46p. Available at: https://escholarship.org/uc/item/94s473v6.

working paper

Why Do Inner City Residents Pay Higher Premiums? The Determinants of Automobile Insurance Premiums

Publication Date

January 1, 2008

Author(s)

Paul Ong

Abstract

Auto insurance rates can vary dramatically, with much higher premiums in poor and minority areas than elsewhere, even after accounting for individual characteristics, driving history and coverage. This project used a unique data set to examine the relative influence of place-based socioeconomic characteristics (or redlining) and place-based risk factors on the place-based component of automobile insurance premiums. We used a novel approach of combining tract-level census data and car insurance rate quotes from multiple companies for sub-areas within the city of Los Angeles. The quotes are for a hypothetical individual with identical demographic and auto characteristics, driving records and insurance coverage. This method allowed the individual demographic and driving record to be fixed. Multivariate models are then used to estimate the independent contributions of these risk and redlining factors to the place-based component of the car insurance premium. We find that both risk and redlining factors are associated with variations in insurance costs in the place-based component, with black and poor neighborhoods being adversely affected, although risk factors are stronger predictors. However, even after risk factors are taken into account in the model specification, SES factors remain statistically significant. Moreover, simulations show that redlining factors explain more of the gap in auto insurance premiums between black (and Latino) and white neighborhoods and between poor and nonpoor neighborhoods. The findings do not appear sensitive to the individual characteristics of the hypothetical driver.

published journal article

MARKOV CHAIN MODELS IN PRACTICE: A REVIEW OF LOW COST SOFTWARE OPTIONS

Investigación Operacional

Publication Date

April 28, 2023

Author(s)

Jiaru Bai, Cristina del Campo, Robin Keller

Abstract

<p><span id="page3R_mcid27" class="markedContent"><span dir="ltr" style="left: calc(var(–scale-factor)*100.34px); top: calc(var(–scale-factor)*263.71px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.939886);" role="presentation">Markov processes (or Markov chains) are used for modeling a phenomenon in which changes over time of a random variable</span> <span dir="ltr" style="left: calc(var(–scale-factor)*100.34px); top: calc(var(–scale-factor)*272.95px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.91935);" role="presentation">comprise a sequence of values in the future, each of which depends only on the immediately preceding state, not on other past</span> <span dir="ltr" style="left: calc(var(–scale-factor)*100.34px); top: calc(var(–scale-factor)*282.19px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.915678);" role="presentation">states. A Markov process (PM) is completely characterized by specifying the finite set S of possible states and the stationary</span> <span dir="ltr" style="left: calc(var(–scale-factor)*100.34px); top: calc(var(–scale-factor)*291.31px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.934392);" role="presentation">probabilities (i.e. time-invariant) of transition between these states.</span></span><span id="page3R_mcid28" class="markedContent"> <span dir="ltr" style="left: calc(var(–scale-factor)*318.67px); top: calc(var(–scale-factor)*291.31px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.987133);" role="presentation">The</span></span><span id="page3R_mcid29" class="markedContent"></span><span id="page3R_mcid30" class="markedContent"> <span dir="ltr" style="left: calc(var(–scale-factor)*333.07px); top: calc(var(–scale-factor)*291.31px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.952517);" role="presentation">software</span></span><span id="page3R_mcid31" class="markedContent"></span><span id="page3R_mcid32" class="markedContent"> <span dir="ltr" style="left: calc(var(–scale-factor)*362.47px); top: calc(var(–scale-factor)*291.31px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.888688);" role="presentation">mos</span></span><span id="page3R_mcid33" class="markedContent"><span dir="ltr" style="left: calc(var(–scale-factor)*375.82px); top: calc(var(–scale-factor)*291.31px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.879561);" role="presentation">t used</span></span><span id="page3R_mcid34" class="markedContent"></span><span id="page3R_mcid35" class="markedContent"> <span dir="ltr" style="left: calc(var(–scale-factor)*396.82px); top: calc(var(–scale-factor)*291.31px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.937188);" role="presentation">in medical applications</span></span><span id="page3R_mcid36" class="markedContent"></span><span id="page3R_mcid37" class="markedContent"> <span dir="ltr" style="left: calc(var(–scale-factor)*473.02px); top: calc(var(–scale-factor)*291.31px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.901263);" role="presentation">is</span></span><span id="page3R_mcid38" class="markedContent"></span><span id="page3R_mcid39" class="markedContent"> <span dir="ltr" style="left: calc(var(–scale-factor)*480.34px); top: calc(var(–scale-factor)*291.31px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.935546);" role="presentation">produced by </span></span><span id="page3R_mcid40" class="markedContent"><span dir="ltr" style="left: calc(var(–scale-factor)*100.34px); top: calc(var(–scale-factor)*300.55px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.969267);" role="presentation">TreeAge</span></span><span id="page3R_mcid41" class="markedContent"><span dir="ltr" style="left: calc(var(–scale-factor)*128.18px); top: calc(var(–scale-factor)*300.55px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif;" role="presentation">,</span></span><span id="page3R_mcid42" class="markedContent"> <span dir="ltr" style="left: calc(var(–scale-factor)*132.26px); top: calc(var(–scale-factor)*300.55px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.942177);" role="presentation">since it offers</span></span><span id="page3R_mcid43" class="markedContent"></span><span id="page3R_mcid44" class="markedContent"> <span dir="ltr" style="left: calc(var(–scale-factor)*177.89px); top: calc(var(–scale-factor)*300.55px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.933813);" role="presentation">many</span></span><span id="page3R_mcid45" class="markedContent"></span><span id="page3R_mcid46" class="markedContent"> <span dir="ltr" style="left: calc(var(–scale-factor)*197.69px); top: calc(var(–scale-factor)*300.55px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.932563);" role="presentation">advantages to the user. But, the cost of the Treeage software is relatively high.</span></span><span id="page3R_mcid47" class="markedContent"> <span dir="ltr" style="left: calc(var(–scale-factor)*454.42px); top: calc(var(–scale-factor)*300.55px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.964072);" role="presentation">Therefore in this</span></span><span id="page3R_mcid48" class="markedContent"> <span dir="ltr" style="left: calc(var(–scale-factor)*100.34px); top: calc(var(–scale-factor)*309.79px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.927866);" role="presentation">article two software alternatives are presented: Sto Tree</span></span><span id="page3R_mcid49" class="markedContent"></span><span id="page3R_mcid50" class="markedContent"> <span dir="ltr" style="left: calc(var(–scale-factor)*280.63px); top: calc(var(–scale-factor)*309.79px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.927152);" role="presentation">and</span></span><span id="page3R_mcid51" class="markedContent"></span><span id="page3R_mcid52" class="markedContent"> <span dir="ltr" style="left: calc(var(–scale-factor)*294.31px); top: calc(var(–scale-factor)*309.79px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.88554);" role="presentation">the zero cost ad</span></span><span id="page3R_mcid53" class="markedContent"><span dir="ltr" style="left: calc(var(–scale-factor)*344.35px); top: calc(var(–scale-factor)*309.79px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif;" role="presentation">d</span></span><span id="page3R_mcid54" class="markedContent"><span dir="ltr" style="left: calc(var(–scale-factor)*348.43px); top: calc(var(–scale-factor)*309.79px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif;" role="presentation">-</span></span><span id="page3R_mcid55" class="markedContent"><span dir="ltr" style="left: calc(var(–scale-factor)*350.95px); top: calc(var(–scale-factor)*309.79px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.957184);" role="presentation">in package "markovchain" implemented in R. An</span></span><span id="page3R_mcid56" class="markedContent"> <span dir="ltr" style="left: calc(var(–scale-factor)*100.34px); top: calc(var(–scale-factor)*318.91px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.909639);" role="presentation">example of a cost</span></span><span id="page3R_mcid57" class="markedContent"><span dir="ltr" style="left: calc(var(–scale-factor)*156.62px); top: calc(var(–scale-factor)*318.91px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif;" role="presentation">-</span></span><span id="page3R_mcid58" class="markedContent"><span dir="ltr" style="left: calc(var(–scale-factor)*159.29px); top: calc(var(–scale-factor)*318.91px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.932854);" role="presentation">effectiveness analysis of two possible treatments for advanced cervical cancer, previously conducted with the</span></span><span id="page3R_mcid59" class="markedContent"> <span dir="ltr" style="left: calc(var(–scale-factor)*100.34px); top: calc(var(–scale-factor)*328.15px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.927157);" role="presentation">Treeage software, is re</span></span><span id="page3R_mcid60" class="markedContent"><span dir="ltr" style="left: calc(var(–scale-factor)*173.21px); top: calc(var(–scale-factor)*328.15px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif;" role="presentation">-</span></span><span id="page3R_mcid61" class="markedContent"><span dir="ltr" style="left: calc(var(–scale-factor)*175.85px); top: calc(var(–scale-factor)*328.15px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.916132);" role="presentation">analyzed with these two low cost software packages.</span></span> <span id="page3R_mcid63" class="markedContent"><span dir="ltr" style="left: calc(var(–scale-factor)*100.34px); top: calc(var(–scale-factor)*337.27px); font-size: calc(var(–scale-factor)*8.04px); font-family: sans-serif; transform: scaleX(0.95059);" role="presentation">You can find a Spanish version of this paper in the following link: http://faculty.sites.uci.edu/lrkeller/publications</span></span></p>

Suggested Citation
Jiaru Bai, Cristina del Campo and L. Robin Keller (2023) “MARKOV CHAIN MODELS IN PRACTICE: A REVIEW OF LOW COST SOFTWARE OPTIONS”, Investigación Operacional, 38(1). Available at: https://revistas.uh.cu/invoperacional/article/view/4420 (Accessed: September 10, 2025).

published journal article

Is the Journey to Work Explained by Urban Structure?

Urban Studies

Publication Date

November 1, 1993

Abstract

Basic to several key issues in current urban economic theory and public policy is a presumption that local imbalances between employment and residential sites strongly influence people’s commuting patterns. We examine this presumption by finding the commuting pattern for the Los Angeles region in 1980 which would minimise average commuting time or distance, given the actual spatial distributions of job and housing locations. We find that the amount of commuting required by these distributions is far less than actual commuting, and that variations in required commuting across job locations only weakly explain variations in actual commuting. We conclude that other factors must be more important to location decisions than commuting cost, and that policies aimed at changing the jobs-housing balance will have only a minor effect on commuting.

Suggested Citation
Genevieve Giuliano and Kenneth A. Small (1993) “Is the Journey to Work Explained by Urban Structure?”, Urban Studies, 30(9), pp. 1485–1500. Available at: 10.1080/00420989320081461.

policy brief

Evaluating Equity in Transportation and Hazard Preparedness Plans: A Multi-Level Governance Approach

Abstract

Environmental justice (EJ) principles are essential for addressing inequities in transportation and hazard preparedness; however, they are often applied in a fragmented manner. Historically, urban planning in the United States has created racial and economic divisions, particularly through policies like redlining and freeway construction that displaced communities of color. These practices have systematically and disproportionately exposed marginalized groups to environmental harms. The EJ movement has advocated for addressing these disparities through equity-focused policies. However, the integration of EJ principles into plans remains incomplete, with prior studies focusing on individual plans or jurisdictions, failing to consider broader governance systems and the need for equity to bridge multiple plan types. These challenges are compounded by the shift from centralized to decentralized governance, creating a fragmented landscape where different levels of government and departments operate with distinct priorities. Multi-level governance (MLG) creates both opportunities and challenges for equity-centered planning. While it enables state funding, regional planning, and local implementation to align, fragmented jurisdictions often leave transportation, hazard, and climate plans in silos. Intentional coordination is needed to embed EJ principles across all levels of planning. This analysis focuses on Los Angeles due to its overlapping jurisdictions, large transit system, and history of environmental injustice making it a critical test case for how MLG can both enable and constrain equity-centered planning. This policy brief is based on our evaluation of 16 climate action, racial equity, transportation, and hazard preparedness plans in Greater Los Angeles, which was systematically scored based on three existing EJ pillars: Recognition Justice, Procedural Justice, and Distributive Justice

Suggested Citation
Jeannine Marie Pearce, Nicola Ulibarri and Elisa Borowski (2025) Evaluating Equity in Transportation and Hazard Preparedness Plans: A Multi-Level Governance Approach. Policy Brief. Available at: https://ezid.cdlib.org/id/doi:10.7922/G28G8J3M (Accessed: September 16, 2025).

conference paper

Effect of route choice models on estimation of travel time reliability under demand and supply variations

Proceedings, First International Symposium on Transportation Network Reliability

Publication Date

January 1, 2002

Author(s)

Suggested Citation
A. Chen, Z. Ji and W. W. Recker (2002) “Effect of route choice models on estimation of travel time reliability under demand and supply variations”, in Proceedings, First International Symposium on Transportation Network Reliability. Kyoto.

Phd Dissertation

Neural network models for automated detection of lane-blocking incidents on freeways

Abstract

A major source of urban freeway delay in the United States is non-recurring congestion caused by incidents such as accidents, disabled vehicles, spilled loads, temporary maintenance and construction activities, signal and detector malfunctions, and other special and unusual events that disrupt the normal flow of traffic. The automated detection of freeway incidents is an important function of a freeway traffic management center. Early detection of incidents is vital for formulating effective response strategies such as timely dispatch of emergency services and incident removal crews, control and routing of traffic around the incident location, and provision of real-time traffic information to motorists. A number of incident detection algorithms, based on conventional approaches, have been developed over the past several decades, and a few of them are being deployed at urban freeway systems in major cities. These conventional algorithms have met with varying degree of success in their detection performance. In this research, a new incident detection technique based on an artificial neural network approach has been proposed. The objective of this research was to demonstrate the use of artificial neural network models for automated detection of lane-blocking incidents on urban freeways. The study focused on the application of neural network models in classifying traffic surveillance data obtained from inductive loop detectors, and the use of the classified output to detect an incident. Three types of neural network models were developed to detect lane-blocking incidents: the multi-layer feed-forward neural network, self-organizing feature map and adaptive resonance theory 2. The models were developed with simulation data from a study site and tested with both simulation and field data at the study site and other locations. The multi-layer feed-forward neural network was found to have the highest potential among the four models to achieve a better incident detection performance. This network consistently detected most of the lane-blocking incidents and gave a false alarm rate lower than the conventional algorithms currently in use. The results have demonstrated the potential of artificial neural network models in improving incident detection performance over currently available techniques.

Suggested Citation
Kelvin Cheu (1994) Neural network models for automated detection of lane-blocking incidents on freeways. PhD Dissertation. UC Irvine. Available at: https://uci.primo.exlibrisgroup.com/permalink/01CDL_IRV_INST/1go3t9q/alma991035092925704701.

working paper

Location and Transportation Strategies in Public Facility Planning

Publication Date

November 1, 1977

Author(s)

Andrew N. White

Working Paper

UCI-ITS-WP-77-8

Abstract

Public facility planning is currently viewed in terms of structuring a service delivery system for optimal provision. Because the spatial process of delivery has been neglected, however, the means of improving service utilization have been narrowly construed as locational in nature. Consequently, facility systems have been modeled and evaluated in terms of supply rather than use, and decentralization has been advocated to the exclusion of alternative spatial patterns. An expanded planning framework regards service delivery as a spatial interaction system and identifies location and transportation as complementary spatial strategies which enhance service utilization and widen the choice of facility pattern. Transportation strategies are more flexible, though, since they directly enhance travel behavior and service accessibility. Moreover, given present planning constraints, transportation strategies have a much wider role to play in improving the effectiveness of future public facility planning and spatial policy. 

Suggested Citation
Andrew N. White (1977) Location and Transportation Strategies in Public Facility Planning. Working Paper UCI-ITS-WP-77-8. Institute of Transportation Studies, Irvine. Available at: https://escholarship.org/uc/item/6sr9z05m.

Phd Dissertation

Activity-based travel demand model with time-use and microsimulation incorporating intra-household interactions

Abstract

The activity-based travel demand model recognizes that travel is derived from the demand for activity participation distributed in space. The focus on intra-household interactions and linkages between people’s behavior and social and physical environment has been identified as emerging features of the activity-based approach that would be important to travel behavior research. The dissertation is dedicated to an in-depth exploration of the within-household interactions by theoretical specification and empirical development of the household activity time allocation models based on a utility maximization framework with the household as the unit of analysis. Furthermore, the dissertation also aims to propose a model of the household activity scheduling process primarily focusing on task allocation mechanisms on the basis of the human agents adjusting themselves to the built social and physical environment. Development of the activity time allocation model in this dissertation includes two types of structural time allocation models. First, the collective models based on two assumptions that household heads have their own utility functions and that decisions by them reach Pareto-efficient outcomes are introduced to develop intra-household activity time allocation models for leisure demand and housework activity. Secondly, intra-household time allocation to housework activity is further examined through the estimation of time allocation to the different types of activities by the different types of household members along with extensive exploration of various theories and identification of related interactions. This dissertation proposes a household activity scheduling process with a model design based on a weekly pattern system, which is expected to keep various advantages compared to a deterministic daily model system. Along with learning and adaptation procedures, the human being as a learning agent is designed to prepare strategic schedules of behavior to achieve individual goals through interactive environments, and implement those plans via activity execution. At the household level, the household and its members as decision agents are also designed to optimize the allocation of the available household labor resource under the presence of the uncertainties of the physical and social environments. After describing the mathematical framework and solution procedure, a simulation experiment is conducted within a hypothetical environment to demonstrate how the proposed model works.

Suggested Citation
Hee-Kyung Kim (2008) Activity-based travel demand model with time-use and microsimulation incorporating intra-household interactions. Ph.D.. University of California, Irvine. Available at: https://uci.primo.exlibrisgroup.com/permalink/01CDL_IRV_INST/17uq3m8/alma991035093055004701 (Accessed: October 14, 2023).

working paper

Chaining Behavior in Urban Tripmaking: Appendices to Interim Report

Publication Date

February 1, 1983

Author(s)

Will Recker, Michael McNally, Gregory Root, Patricia K. Lyon, Mark A. Smiley, Carleton Waters

Working Paper

UCI-ITS-WP-83-9, UCI-ITS-AS-WP-83-2

Areas of Expertise

Suggested Citation
Will Recker, Michael G. McNally, Gregory S. Root, Patricia K. Lyon, Mark A. Smiley and Carleton D. Waters (1983) Chaining Behavior in Urban Tripmaking: Appendices to Interim Report. Working Paper UCI-ITS-WP-83-9, UCI-ITS-AS-WP-83-2. Institute of Transportation Studies, Irvine. Available at: https://escholarship.org/uc/item/94b4701w.