Recent uctc_fr items

Risk Assessment and Risk Management for Transportation Research

Mon, 11 May 2026 00:00:00 +0000

This paper sets forth a preliminary methodology to assess and manage risk for transportation research. The California Dept. of Transportation (Caltrans) funds numerous transportation research projects that range from studies that aim to improve the understanding of travel behavior to field operations tests and deployment studies for new technologies. The risk assessment methodology is designed to help 1) identify needs for transportation research, 2) identify likely audiences for the anticipated research products, as well as potential applications; 3) identify potential barriers that could impede research or prevent its implementation; and based on the findings of the first three steps, 4) assess whether Caltrans is best suited to fund and oversee the research, should co-‐sponsor it with other agencies, should support it in less direct ways, or should refrain from engaging in research efforts on the topic and simply monitor developments in the field. The methodology is intended...

Innovative DOTs: Identifying Critical Issues and Strategies with Broad Support

Mon, 11 May 2026 00:00:00 +0000

Many state Departments of Transportation (DOTs) are engaged in strategic planning aimed at helping them improve their ability to identify coming problems and improve their ability to innovate. This paper examines common concerns or 'threats' currently facing DOTs, and identifies strategies to address them, or 'opportunities' that many DOTs support. The paper gives examples of innovative projects and programs from DOTs around the U.S., across a spectrum from leading innovative agencies to those just starting to initiate a discussion about change. Our methodology was to scan recent reports on critical issues and changing trends from a variety of experts and transportation stakeholder groups representing a broad selection of viewpoints. We then sought examples of how DOTs are currently innovating to address these critical issues and changing trends—both opportunities and threats—and identified ten main ways in which DOTs are adapting to meet them. Many reports on innovative DOTs...

Psychological economics, travel behavior, residential location choice, and sustainability: Possible new rationales for policy intervention

Wed, 12 Nov 2025 00:00:00 +0000

The sustainability policy agenda includes various land use, road pricing, and parking pricing policies that are intended to reduce the use and ownership of autos in order to lower carbon emissions, pollution and road congestion. Such well-established policy interventions are largely rooted in the microeconomic concepts of market failure and externalities. But recent research in psychological economics has identified a new kind of problem: people may make decisions that are not in their own self-interest, contrary to the underlying microeconomic assumption that people are “rational actors.” This research in progress explores whether and how imperfect decision making significantly affects the choice of where to live and how to travel, with effects on the sustainability of urban growth. The psychological economics literature suggests that residential movers may systematically over-predict future housing and commute satisfaction. They may also fail to consider less salient criteria...

The Role of Behavioral Economics in Residential Choice: A Pilot Study Of Travel Patterns, Housing Characteristics, Social Connections, and Subjective Well-Being

Fri, 7 Nov 2025 00:00:00 +0000

Do people make imperfect decisions about where to live and how to travel? There is some evidence that people may overvalue privacy and material goods like housing and undervalue time for activities and social connections. We surveyed 84 individuals, almost all of them university students, before and after a planned move between homes. Respondents answered questions at two points in time about six months apart, before and after moving. They reported ratings of subjective well-being, information on travel patterns, characteristics of homes and neighborhoods, the number and type of social connections, demographics, and significant life events. This working paper describes the survey design and data collection process, and reports on survey results.

Overcoming battery life problems of smartphones when creating automated travel diaries

Thu, 18 Sep 2025 00:00:00 +0000

Gathering data using travel diaries has been a requirement to analyze travel behaviour data for decades. Traditional pen and paper techniques of gathering data has been complemented by new technologies, most recently GPS loggers, and now smartphones. Smartphones appear to be the silver bullet in collecting travel data on a wide scale, they are widespread, applications are easy to distribute, and the hardware is reliable. However, conserving the battery life in smartphones is a challenge to creating automated travel diaries. The smartphone is not solely a travel diary tool and for a system to work, the travel diary application cannot be a burden to the user. In this paper we leverage work from the “everyday location monitoring” research community in a system to sparsely collect location data from smartphones in a battery efficient manner. With this sparse data, we present an algorithm to generate trips, and suggest six metrics to analyze the quality of the trip determination system....

The Quantified Traveler: Changing transport behavior with personalized travel data feedback

Thu, 18 Sep 2025 00:00:00 +0000

Experiments using smartphones to influence behavior have been growing rapidly in many fields, especially in health and fitness research, and studies on eco-feedback technologies. In these studies, users are first tracked to understand their baseline behaviors, then measured continuously while they receive feedback about their actions. In transportation, studies using smartphones to change behavior have been limited due to the difficulty in even tracking users in the first place. Collecting data from smartphones in a battery efficient manner is a large research problem, and behavior change studies depend on being able to track travel behaviors. We developed an automated travel diary system which efficiently and unobtrusively collected travel data using smartphones and ran an experiment to evaluate how people’s awareness of their transportation behavior, attitudes towards sustainable transportation, intentions to change behavior, and measured travel behavior changed. For three weeks,...

Bay Bridge Toll Evaluation: Final Report

Fri, 25 Jul 2025 00:00:00 +0000

On July 1, 2010, the Bay Area Toll Authority (BATA) raised the tolls on the seven state‐ owned bridges in the San Francisco Bay Area. For six of the bridges, a flat $5 toll was implemented for passenger vehicles with a 50% discount ($2.50 toll) for peak‐period 3+ person carpools, which had previously crossed the bridges free of charge. On the San Francisco‐ Oakland Bay Bridge, a more complex toll structure was put into place. The toll was increased to $6 during weekday peak periods (5‐10 a.m. and 3‐7 p.m.), and the off‐peak weekday toll was left unchanged at $4. The peak period 3+ person carpool toll was set at $2.50, the same as on other bridges.

Old Road, New Directions

Wed, 11 Sep 2024 00:00:00 +0000

Old Road, New Directions

Drivers' Willingness-to-Pay to Reduce Travel Time: Evidence from the San Diego I-15 Congestion Pricing Project

Mon, 7 Oct 2013 00:00:00 +0000

The adoption of congestion pricing depends fundamentally upon drivers' willingness to pay to reduce travel time during the congested morning peak period. Using reveled preference data from congestion pricing demonstration project San Diego, we estimate that willingness to pay to reduce congested travel time is higher than previous stated preference results. Our estimate of median willingness to pay to reduce commute time is rouhgly $30 per hour, although this may be biased upward by drivers' perception that the toll facility provides safer driving conditions. Drivers aslo use the posted toll as an indicator of abnormal congestion and increase thier usage of the toll facility when tolls are higher than normal.

Trends in California's Jobs

Mon, 7 Oct 2013 00:00:00 +0000

Employment and the journey to work have long been a focus of transportation study. Although today, the work trip accounts for a much smaller share of total trips than it did a few decades ago, there are several reasons why this subject deserves our continued attention.

In planning for the journey to work, it is important to have an understanding of the anticipated growth in jobs in the coming years. Both the location of job growth and the types of jobs are important; the geographical distribution of jobs will affect transport needs, and different industries and occupations are associated with different land use patterns and transportation behaviors.

This paper presents a review and analysis of California's job trends.

The Quantified Traveler: Changing transport behavior with personalized travel data feedback

Fri, 13 Sep 2013 00:00:00 +0000

Experiments using smartphones to influence behavior have been growing rapidly in many fields, especially in health and fitness research, and studies on eco-feedback technologies. In these studies, users are first tracked to understand their baseline behaviors, then measured continuously while they receive feedback about their actions. In transportation, studies using smartphones to change behavior have been limited due to the diﬃculty in even tracking users in the first place. Collecting data from smartphones in a battery eﬃcient manner is a large research problem, and behavior change studies depend on being able to track travel behaviors. We developed an automated travel diary system which eﬃciently and uobtrusively collected travel data using smartphones and ran an experiment to evaluate how people’s awareness of their transportation behavior, attitudes towards sustainable transportation, intentions to change behavior, and measured travel behavior changed. For three weeks, 135...

Quantified Traveler: Travel Feedback Meets the Cloud to Change Behavior

Fri, 13 Sep 2013 00:00:00 +0000

We describe the design and evaluation of a system named Quantified Traveler (QT). QT is a Computational Travel Feedback System. Travel Feedback is an established programmatic method whereby travelers record travel in diaries, and meet with a counselor who guides her to alternate mode or trip decisions that are more sustainable or otherwise beneficial to society, while still meeting the subject’s mobility needs. QT is a computation surrogate for the counselor. Since counselor costs can limit the size of travel feedback programs, a system such as QT at the low costs of cloud computing, could dramatically increase scale, and thereby sustainable travel. QT uses an app on the phone to collect travel data, a server in the cloud to process it into travel diaries and then a personalized carbon, exercise, time, and cost footprint. The subject is able to see all of this information on the web. We evaluate with 135 subjects to learn if subjects let us use their personal phones and data-plans...

Land-Use Mixing and Suburban Mobility

Fri, 28 Jun 2013 00:00:00 +0000

SUBURBAN traffic congestion has emerged as one of the most pressing problems in the transportation field today and, most probably, will hold center stage in the transportation policy arena for years to come. Most accounts link the suburbanization of congestion to the suburbanization of jobs during the 1980s.1 Indeed, recent surges in suburban office employment have fundamentally altered commuting patterns, giving rise to,far more cross-town, reverse-direction, and lateral travel movements than in years past. This dispersal of jobs and commuting has been a mixed blessing of sorts. While on theone hand it has relieved some downtowns of additional traffic and brought jobs closer to some suburbanites, on the other hand it has flooded many outlying thoroughfares with unprecedented volumes of traffic and seriously threatened the very quality of living that lured millions of Americans to the suburbs in the first place.

Setting the Stage for National Transportation Policy to the Year 2020: The Surface Transportation and Uniform Relocation Assistance Act of 1987

Fri, 28 Jun 2013 00:00:00 +0000

Not widely known to the public policy community outside transportation is the fact that the Interstate Highway System is almost finished. By 1992, if all goes as planned, the United States will have a completed, fully mature Interstate transportation system. Even less known is the fact that federal gas taxes could be extended, thus revenues would continue to "roll" in.

So large a "pot of gold" is enormous temptation. It tantalizes other underfunded public services, that may mistakenly believe surface transportation has had its day. In part anticipating a "raid," the surface transportation technical community is developing a coalition, the "2020 Plan," to build a consensus similar to the pre-Interstate era (1955-56). successful, future surface transportation needs will continue to be funded by gas tax revenues from the highway trust fund.

Car Ownership and Welfare-to-Work

Fri, 28 Jun 2013 00:00:00 +0000

This study examines the role of car ownership in facilitating employment among recipients under the current welfare-to-work law. Because of a potential problem with simultaneity, the analysis uses an instrumental variable constructed from insurance premiums and population density for car ownership. The data comes from a 1999-2000 survey of TANF recipients in the Los Angeles metropolitan area. The empirical results show a significant independent contribution of car ownership on employment. The presence of an observed ownership is associated with 12 percentage point increase in the odds of being employed. Moreover, the results indicate that lowering insurance premiums by $100 can increase the odds of employment by 4 percentage points.

New Vehicle Choices, Fuel Economy and Vehicle Incentives: An Analysis of Hybrid Tax Credits and Gasoline Tax

Fri, 28 Jun 2013 00:00:00 +0000

Automobiles impose considerable public costs in the form of emissions and foreign oil dependence. Public policy has thus taken a considerable interest in influencing the technology and fuel economy associated with new vehicles brought to market. In spite of this interest, there is very limited information on the effectiveness of these policies in reducing greenhouse gas emissions or shifting vehicle demands. This is in part due to the fact that modeling the demand for automobiles is wrought with many challenges. These include large choice sets that change frequently over time and significant data collection obstacles. This work proposes a methodology for data development that simplifies many of the challenges associated with data collection in automotive modeling. The methodology explores a technique to merge data on aggregate sales with disaggregate vehicle holdings data to synthesize a complete dataset that preserves the strengths of both. The merged dataset is used to...

Segregation by Racial and Demographic Group: Evidence from the San Francisco Bay Area

Fri, 28 Jun 2013 00:00:00 +0000

This paper considers residential segregation by race and by type of household in 1970 and 1980. The paper presents entropy indices of segregation for the San Francisco Bay Area and its five metropolitan areas. The methodology permits an investigation of the effects of group definition upon segregation measures, and an analysis of the degree of independence in the segregation of households by race and demographic group. The results indicate that the levels of segregation by race and by household type have declined modestly during the 1970s, at least in this region. More importantly, however, the results indicate a remarkable independence in the spatial distribution of households by race and demographic group. Only a very small fraction of the observed levels of segregation by race could be ’explained’ by the prior partitioning of households by demographic group. The principal results of the analysis are invariant to changes in the definition of racial or household groups.

Modeling Land Use and Transportation: An Interpretive Review for Growth Areas

Fri, 28 Jun 2013 00:00:00 +0000

Urban growth is taking new forms in recently urbanized or formerly suburban areas, characterized by low density, heavy dependence on automobile transportation, and multiple activity centers. In order to understand better such ’contemporary urban areas’, researchers need land-use models that realistically capture the key features of such areas and that Can handle detailed data sets.

We review the literature on large-scale land-use modeling with this objective in mind. Characterizing the known models along several dimensions describing purpose, Conceptual basis, mathematical content, and level of detail, we select models that are representative of the range of approaches taken. Six of these are reviewed in detail, and four others are discussed more briefly.

We find that the existing literature forces one to choose between tractability and suitability for contemporary urban areas, The key omission in the tractable models is economies of agglomeration that would help...

Structural Equation Modeling of Travel Choice Dynamics

Fri, 28 Jun 2013 00:00:00 +0000

This research has two objectives. The first objective is to explore the use of the modeling tool called "latent structural equations" (structural equations with latent variables) in the general field of travel behavior analysis and the more specific field of dynamic analysis of travel behavior. The second objective is to apply a latent structural equation model in order to determine the causal relationships between income, car ownership, and mobility.

Electric Vehicles: Performances, Life Cycle Costs, Emissions, and Recharging Requirements

Fri, 28 Jun 2013 00:00:00 +0000

Electric vehicles (EV) are periodically promoted as quiet, pollution-free alternatives gasoline vehicles. They have failed each time because of inferior performance and high costs. In this paper, we conduct an updated and detailed evaluation of the performance, costs, environmental impacts, and recharging requirements of electric vehicles. We find that considerable progress has been made in EV battery and powertrain technology since the last surge of interest in EVs in the 1970s. If the development of high-performance batteries continues as expected, advanced electric vehicles could have an urban range of over 150 miles and acceleration comparable to that provided by internal combustion engine vehicles (ICEVs). And if optimistic battery cost, life, and performance goals are achieved, massproduced EVs will have lower life-cycle costs than comparable conventional gasoline vehicles. EVs will reduce emissions per mile of HC, CO. and NO,, compared to stringently controlled ICEVs....

Modeling Earnings Measurement Error: A Multiple Imputation Approach

Fri, 28 Jun 2013 00:00:00 +0000

Recent survey validation studies suggest that measurement error in earnings data is pervasive and violates classical measurement error assumptions, and therefore may bias estimation of cross-section and longitudinal earnings models. We model the structure of earnins measurements error using data from the Panel Study of Income Dynamics Validation Study (PSIDVS). We then use Rubin's (1987) multiple imputation techniques to estimate consistent earnings equations under non-classical earnings measurement error in PSID. Our technique is readily generalized, and the empirical results demonstrate the potential importance of correcting for measurement error in earnings and related data, particularly during recessions.

Structural Equation Modeling For Travel Behavior Research

Fri, 28 Jun 2013 00:00:00 +0000

Structural equation modeling (SEM) is an extremely flexible linear-in-parameters multivariate statistical modeling technique. It has been used in modeling travel behavior and values since about 1980, and its use is rapidly accelerating, partially due to the availability of imporved software. The number of published studies, now known to be more than fifty, has approximatley doubled in the pas three years. This review of SEM is intended to provide an introduction to the field for those who have not used the method, and the compendium of applications for those who wish to compare experiences and avoid the pitfall of reinventing previous research.

Aggression on Roadways

Fri, 28 Jun 2013 00:00:00 +0000

Aggression and the automobile have had a long standing association, yet research on aggressive behavior has neglected the roadway context. This chapter reviews exisdng work which has included archival analysis, field interview studies, personality research, and field experiments. Among the recurrent themes have been the relationship between aggressivity in driving to accident liability and to violence in the larger social context.. Validity issues in road aggression research are discussed, and a typology of roadway aggression is presented. The typology maps a range of contemporary forms, most of which have never been invesngated scientifically and have received sparse academic attention otherwise, despite having high soCial and scientific relevance. Disinhibiting influences that heighten the probability of roadway aggression are discussed.

A Joint Household Travel Distance Generation and Car Ownership Model

Fri, 28 Jun 2013 00:00:00 +0000

The product of this research is a dynamic simultaneous equations model of car ownership and modal travel distances as a function of income. The data are from the Dutch National Mobility Panel (1984-1987); and four modes are encompassed: car driver, car passenger, trainl and bus-tram-subway. A novel feature of the simultaneous equation system is the consistent treatment of the measurement scales of the variables: ordered probit functions for income and car ownership and tobit functions for distances. The dynamics are expressed in terms of pooled panel survey measurements of the variables at two points in time one year apart, This allows the identification of lagged responses and serial correlations over a one-year time-horizon. Results indicate that increased car ownership and car kilometers at time T., is influenced bv heavy usage of other modes at time T~. This indicates there are significant noninstantaneous a~ljustments of car ownership and usage that represent modal substitutions.

Planning for the Transportation Needs of Welfare Participants: Institutional Challenges to Collaborative Planning

Fri, 28 Jun 2013 00:00:00 +0000

The responsibility for developing transportation programs for welfare participants spans multiple public agencies. Consequently, federal funding programs require that agencies work together to develop a coordinated response to addressing the transportation needs of welfare participants. Based on a survey of transportation, welfare and employment agencies in 19 California counties, this study examines the potential institutional obstacles to successful local collaboration and coordination among public agencies. The research shows that new sources of federal funds have encouraged interagency efforts to address the transportation needs of welfare participants. However, the divergent organizational goals, methods, and approaches of the participating agencies heavily influence these collaborative efforts. As a consequence, stakeholders may have difficulty moving beyond the narrow interests of their individual institutions to identify and plan for the transportation needs of welfare...

Transportation Technologies: Implications for Planning

Fri, 28 Jun 2013 00:00:00 +0000

Transportation is rapidly being changed by new technologies, such as Intelligent Transportation Systems (including smart cards, on-board diagnostics and information systems, and smarter highways, transit, automobiles, logistics systems, and other information systems). the range of options and their impacts will continue to expand as new technologies are introduced over the next two decades, and may alter transportation systems in many ways. For example, electric, hydrogen, or hybrid electric-petroleum vehicles may be introduced that would substantially alter emissions and fuel characteristics of the fleet, and potentially pose challenges in terms of system operations and finance. Smart card technologies could greatly improve the feasibility and convenience of a variety of pricing options for road use, parking, and transit fares. Monitoring and information systems could enable travelers to time trips and select routes to avoid congestion, reducing it in the process. Advanced...

Multiply Imputed Sampling Weights for Consistent Inference with Panel Attrition

Fri, 28 Jun 2013 00:00:00 +0000

This chapter demonstrates a new methodology for correcting panel data models for attrition bias. The method combines Rubin's Multiple Implication technique with Manski and Lerman's Weighted Exogenous Sample Maximum Likelihood Estimator (WESMLE). Simple Hausman tests for the presence of attrition bias are also derived. We demonstrate the technique using a dynamic commute mode choice model estimated formt he University of California Transportation Center's Southern California Transportation Panel. The methodology is simpler to use than standard maximum likehood-based procedures. It can be easily modified to use with many panel data estimation and forecasting procedures.

Regulating Traffic by Controlling Land Use: The Southern California Experience

Fri, 28 Jun 2013 00:00:00 +0000

American attitudes toward transportation planning have recently undergone significant change. For three decades after the end of World War II, public policy emphasized the construction of new highway and transit facilities in order to remove the backlog of needs which resulted from the combined effects of depression, a war economy, continued urban growth, and accelerating automobile ownership. For the most part, there was consensus among transportation policymakers that their primary goal was to accommodate growth by constructing facilities which would have adequate capacity to handle future demand. It was understood that land use patterns and economic development were the sources of traffic, yet there was general agreement that transportation policy should aim to accommodate forecast land use and economic growth rather than to regulate them in order to control traffic.

Traffic Congestion and Trucking Managers' Use of Automated Routing and Scheduling