bluuebunny/crossref_metadata_2025 huggingface dataset:
Equity Measures and Their Performance in Transportation
Authors: Ramjerdi Farideh
Published: May 2018

This paper aims at equity implications of transportation policies by using a range of equity measures in two case studies. Different measures of inequality embrace different normative judgments. Early studies have warned about placing too much trust in a single measure. One approach is to address equity considerations by assuming an explicit form of social welfare function and the choice of a desired inequality aversion parameter. A second approach is to apply an inequality measure to a given pair of distributions of a variable (e.g., income and accessibility) that changes as the result of a policy. The latter approach is adopted in this paper. A partial equilibrium model of transportation is used for the calculation of the changes in income, accessibility, and the net benefit for different social groups. This paper demonstrates the challenges that arise in addressing equity with a partial equilibrium model of transportation. An overview of some equity measures and their properties is provided first. The performances of these equity measures are evaluated for alternative road pricing schemes for Oslo, Norway. The paper illustrates that relating the equity objective to a predefined value of any of these measures is not desirable. It is difficult to make a judgment about the equity implication of a policy on the basis of a single measure and without a thorough examination of several measures. The paper also shows that the sizes of the equity measures are quite sensitive to the level of spatial disaggregation.
Estimation of Fuel Use by Idling Commercial Trucks
Authors: Gaines Linda , Vyas Anant , Anderson John L.
Published: May 2018

This paper uses the recently published 2002 Vehicle Inventory and Use survey to determine the number of commercial trucks in the categories that are most likely to idle for periods of more than 0.5 h at a time. On the basis of estimated numbers of hours for both overnight idling by sleepers and long-duration idling by all size classes during their workdays, the total fuel use by idling trucks is estimated to be more than 2 billion gallons per year. Workday idling is determined to be a potentially much larger energy user than overnight idling, but data are required before any definitive conclusions can be reached. Existing technologies can reduce overnight idling, but development may be needed to reduce workday idling.
Analysis of In-Use Fuel Economy Shortfall by Means of Voluntarily Reported Fuel Economy Estimates
Authors: Greene David L. , Goeltz Rick , Hopson Janet , Tworek Elzbieta
Published: May 2018

The usefulness of the U.S. Environmental Protection Agency's (EPA) passenger car and light truck fuel economy estimates has been the subject of debate for the past three decades. For the labels on new vehicles and the fuel economy information given to the public, the EPA adjusts dynamometer test results downward by 10% for the city cycle and 22% for the highway cycle to better reflect real world driving conditions. These adjustment factors were developed in 1984 and their continued validity has repeatedly been questioned. In March 2005, the U.S. Department of Energy and EPA's fuel economy information website, www.fueleconomy.gov , began allowing users to voluntarily share fuel economy estimates. This paper presents an initial statistical analysis of more than 3,000 estimates submitted by website users. The analysis suggests two potentially important results: ( a) adjusted, combined EPA fuel economy estimates appear to be approximately unbiased estimators of the average fuel economy consumers will experience in actual driving, and ( b) the EPA estimates are highly imprecise predictors of any given individual's in-use fuel economy, an approximate 95% confidence interval being ±7 mpg. These results imply that what is needed is not less biased adjustment factors for the EPA estimates but rather more precise methods of predicting the fuel economy individual consumers will achieve in their own driving.
Hydrogen Delivery Scenario Analysis Model for Hydrogen Distribution Options
Authors: Mintz Marianne , Gillette Jerry , Elgowainy Amgad , Paster Mark , Ringer Matthew , Brown Daryl , Li James
Published: May 2018

As with the distribution of any commodity, distribution of hydrogen depends on how the hydrogen is packaged, how far it must travel, and how much must be delivered. Few would argue that transporting a high-pressure gas is markedly different from transporting a cryogenic liquid—or even a liquid at standard temperature and pressure. Packaging affects not only density (weight/volume) but also the operation of potential delivery modes and onboard storage, a problem that has been called the grand challenge of the hydrogen economy. These three factors—packaging (which in turn affects shipment size and modal attributes), delivery distance, and demand—affect both the structure of potential delivery systems and their contribution to unit costs. This paper describes the hydrogen delivery scenario analysis model, a generalized model of hydrogen delivery that can be used to analyze the economic feasibility of various options for hydrogen distribution to markets of different sizes and types. Inputs may be user defined, or default values developed for the U.S. Department of Energy's Hydrogen Analysis project may be used. This paper describes the model's structure and capabilities, presents initial results, and discusses ongoing enhancements.
Guardrail Run-Out Length Design Procedures Revisited
Authors: Coon Brian A. , Sicking Dean L. , Mak King K.
Published: May 2018

Encroachment data sets by Hutchinson and Kennedy and by Cooper, which are used as the foundation for current guardrail design procedures, are compared with each other and with crash databases. Discrepancies between the two data sets are examined and explained. These encroachment data sets are also compared to available real-world crash data, including new crash data from an ongoing study. The encroachment and crash data evaluations clearly indicate that guardrail length calculation procedures developed from the Cooper encroachment data provide more appropriate guardrail run-out length designs for minimizing injuries and fatalities associated with ran-off-road crashes.
Placement Guidance for Temporary Concrete Barriers in Construction Work Zones
Authors: Porter Richard J. , Mahoney Kevin M. , Ullman Gerald L.
Published: May 2018

An important design decision in construction work zones concerns the use and placement of temporary barriers. The temporary concrete safety shaped barrier is the option preferred by most state transportation agencies. No consensus on specific warrants or nationally recognized guidance exists. Of 32 state departments of transportation responding to a recent survey, 24 ranked having or improving work zone guidance on “traffic barriers and roadside design” as “most important/critical.” The objective of this paper is to investigate and evaluate the information, tools, and procedures available to aid individual designers and agencies in developing guidance for the use of traffic barriers in construction work zones. Principles of roadside barrier use for permanent roadways will be covered. Also covered will be benefit–cost analysis and adaptation of permanent roadway procedures and programs, specifically the Roadside Safety Analysis Program (RSAP), for the purpose of developing work zone barrier guidance. Results show that the modeling of specific work zone scenarios and development of generalized barrier placement guidance for practitioners based on cost-effective principles are both feasible. This type of analysis can be done by adapting algorithms in RSAP intended for permanent roadway analysis to construction work zones. General guidelines similar to the median barrier warrants for permanent roadways in the Roadside Design Guide were developed for construction work zones. In addition, it was concluded that current encroachment models and crash severity indexes may not be well suited for permanent roadways or construction work zones.
Tie-Downs and Transitions for Temporary Concrete Barriers
Authors: Bielenberg Robert W. , Reid John D. , Faller Ronald K. , Rohde John R. , Sicking Dean L.
Published: May 2018

Temporary concrete barriers are one of the most common types of roadside hardware found on the nation's highways. However, unresolved issues exist for some installations. These issues include the need for a tie-down system for barrier installations placed on asphalt roadway surfaces and an approach transition between temporary concrete barriers and rigid barriers. The objective of this research was to design a tie-down temporary barrier for use on asphalt road surfaces and then apply that tie-down system to the design of an approach transition from freestanding to rigid barriers. The tie-down and transition systems were to be evaluated according to Test Level 3 safety performance criteria set forth in NCHRP Report No. 350. For the asphalt tie-down system, three steel pins were installed in holes on the front face of the barrier. The new tie-down design was crash tested according to NCHRP Report No. 350 Test Designation 3-11. The test was judged acceptable, barrier deflections were reduced, and all barriers in the system were safely restrained. The approach transition to rigid barrier was developed through strategic application of the previously designed asphalt tie-downs. Computer simulation with LS-DYNA was used to locate the critical impact point for the full-scale crash test. The system was tested according to NCHRP Report No. 350 Test Designation 3-21. Results show that the vehicle was safely redirected, and the test was judged acceptable. Recommendations concerning the application of both the tie-down and transition designs are given.
Low-Deflection Portable Concrete Barrier
Authors: Bligh Roger P. , Sheikh Nauman M. , Alberson Dean C. , Abu-Odeh Akram Y.
Published: May 2018

Temporary barriers are often required to provide positive protection for motorists and workers in a highway work zone. Most highway work zones are restricted in regard to available lateral space for accommodating traffic and the work activity. Consequently, it is desirable to minimize deflection of work zone barriers to minimize the required buffer distance between the barrier and work activity area and, thereby, maximize the space and number of lanes available for traffic. Under this study, a new connection designed to reduce dynamic deflection of portable concrete traffic barriers was developed through a program of finite element simulation and full-scale crash testing. The new cross-bolted (or X-bolt) connection uses two threaded rods in different horizontal planes across the barrier joint to form a tight, moment connection. It achieves the objective of low dynamic barrier design deflection without sacrificing constructability. In addition to being easy to install, the new barrier system is also perceived to be easy to inspect and repair. Crashworthiness and design deflection of the barrier connection were verified through full-scale crash testing using segment lengths of 10 ft and 30 ft. An F-shape barrier with X-bolt connection was demonstrated to have the lowest deflection of any approved portable concrete barrier.
Test Level 4 Noise Wall for Attachment to Concrete Traffic Barriers
Authors: Faller Ronald K. , Polivka Karla A. , Humphries Eric , Kurz Keith , Sicking Dean L. , Hascall Jason
Published: May 2018

A new transparent noise barrier system was developed for use on rigid bridge railings and other rigid structures. The crashworthy noise barrier system incorporated specially designed, strategically located structural hardware into a noncrashworthy noise barrier system. The noise barrier system was anchored to the back face of a reinforced concrete parapet with vertical steel posts. Transparent sound panels surrounded by a metallic frame were dropped between the spaced posts to create a noise barrier. Three horizontal rails were used to prevent errant vehicles from penetrating into sound panels, snagging on the support posts, or both. The test installation consisted of a 34.56-m-long Paraglas Soundstop TL-4 noise barrier system supported by 18 steel posts. Two full-scale crash tests—one with a single-unit truck and one with a pickup truck—were conducted and reported in accordance with the requirements specified in NCHRP Report No. 350: Recommended Procedures for the Safety Performance Evaluation of Highway Features. The safety performance of the transparent noise barrier system was determined to be acceptable according to Test Level 4 evaluation criteria specified in NCHRP Report No. 350.
Teaching Context-Sensitive Design to Undergraduates
Authors: Parkany Emily
Published: May 2018

Context-sensitive design (CSD), also referred to as context-sensitive solutions, is an increasingly important topic for transportation design engineers. More and more projects need to incorporate community wishes and environmental and land use constraints, integrate historic elements, and blend aesthetically with environs. Introducing CSD explicitly in undergraduate civil engineering classes is a good way to encourage our future engineers to think about design challenges. Resources for teaching CSD are presented here, as well as descriptions of activities and assignments used in university civil engineering courses. A casual survey of students who had been exposed to CSD as undergraduates was conducted. Their responses are provided here. CSD has the benefit of attracting students to transportation design, asking engineers to consider public involvement and interdisciplinary elements in their projects, and addressing some of the new skills recommended for professional engineers. This paper describes why undergraduate engineers should be taught CSD, how CSD should be taught, and what the benefits of teaching CSD to undergraduate engineers are.
Optimizing Facilities Placement and Automating Permit Process for Improved Utility Corridor Development
Authors: Collier Nathaniel O. , Kranc Stanley C.
Published: May 2018

The number of utilities that want to share the transportation right-of-way is rapidly increasing. To promote the best possible allocation of limited resources, a computer-based procedure intended to assist and enhance the routine process of granting permits is suggested. A program strategy has been developed to make an optimization capability available to a permitting agency during examination of the permit application, which is assumed to be filed electronically. The results of this program are intended to provide a basis for granting or denying permits by checking physical constraints to installation, safety, and total cost. The advantage of such a program lies in the ability to examine a large set of possible installation configurations. In cases in which no basis for a simple decision is apparent, a report of this fact is made so that other steps can be taken. The ability to expand occupancy of a corridor at some later date is yet one more consideration relating to the quality of any proposed solution, and this concept is explored as well. The program and examples presented here represent a prototype effort with sufficient generality to be applicable in widely varying circumstances.
Ontological Modeling of Infrastructure Products and Related Concepts
Authors: Osman Hesham , El-Diraby Tamer
Published: May 2018

The large number of infrastructure renewal projects taking place along congested urban transportation corridors poses several challenges for all project proponents. As such, closer integration of processes between all stakeholders is required throughout a project life cycle. This integration can be accomplished through enhancing interorganizational information interoperability. This paper presents ontologies, an emerging tool that is gaining momentum in the computer science field and has great potential to facilitate knowledge sharing and interoperability. A four-layer distributed ontology for representing infrastructure products and related concepts is presented. The root level is a representation of the abstract superclasses (entities and supporting concepts) on which the next levels construct their semantics. The next two levels are considered ontologies specific to the domain of infrastructure products but are created at different levels of detail to maintain consistency with other ontology development efforts. The final level is the application ontology that uses the core knowledge defined at the domain level to create sets of task-specific ontologies. In this paper, an urban infrastructure design coordination ontology is presented. The ontology was then used to build a collaborative system based on the geographic information system to support design coordination of utilities along urban transportation corridors. The system demonstrates how ontologies can be used to streamline the utility design coordination process among utility companies and municipalities.
Applying Branch-and-Bound Technique to Route Choice Set Generation
Authors: Prato Carlo Giacomo , Bekhor Shlomo
Published: May 2018

An algorithm to solve explicitly the path enumeration problem is proposed. This algorithm is based on the branch-and-bound technique and belongs to the class of deterministic methods along with existing approaches that combine heuristic or randomization procedures with shortest-path search. The branch-and-bound algorithm is formulated, and a methodology is designed for the application of deterministic approaches to a real case study. Path sets generated with different methods are compared for behavioral consistency, namely, the ability to reproduce actual routes chosen by individuals driving habitually from home to work. Choice set compositions for modeling purposes are determined for the consistency of the path generation process with the observed behavior. Further, model estimates and performance for different route choice specifications are examined for both path set compositions. Results suggest that the proposed branch-and-bound algorithm generates realistic and heterogeneous routes, reproduces better the observed behavior of the interviewed drivers, and produces a good choice set for route choice model estimation and performance comparison.
Working Retirement
Authors: Srinivasan Nanda , McGuckin Nancy , Murakami Elaine
Published: May 2018

The proportion and number of older workers (those older than 65) are expected to increase significantly in the coming decades, and examining this cohort's travel behavior may provide insight into this potential boom. This study is an exploratory analysis to describe working patterns of the older population today, to examine their work trips, and to make some guesses about how the baby boom generation will be similar to or differ from today's older population. With the available literature on travel by the elderly and data from the 2000 U.S. decennial census and the 2001 National Household Travel Survey, the commute and occupational characteristics of older workers in the work force are explored. Topics covered include projected increase in miles driven by older population groups, trends in labor force participation, occupations of older workers, overall travel patterns, travel time, and mode-to-work characteristics; examination of race and ethnic origin of older workers; and description of the older work-at-home population.
Modeling Individuals’ Frequency and Time Allocation Behavior for Shopping Activities considering Household-Level Random Effects
Authors: Habib Khandker M. Nurul , Miller Eric J.
Published: May 2018

A comprehensive frequency and time allocation modeling system for shopping activities is described. The modeling system is person-based but explicitly considers fixed and random household effects. It has three components: a weekly shopping frequency model, a daily shopping frequency model, and a time allocation model for individual shopping episodes. The frequency models consider activity generation as a latent response—the propensity to participate in shopping activities. This latent response is modeled by using an ordinal response model. Both the weekly and daily frequency models are multilevel ordinal logit models, in which the household is the highest level and the individual is the lowest level. The multilevel ordinal logit models incorporate household-level influences on an individual's shopping behavior in terms of fixed effects and a random intercept. The time allocation models are hazard duration models that consider household-level random heterogeneity. The entire modeling system is sequential from the weekly frequency component to the time allocation component. The outputs of the earlier components enter as inputs to the later components: weekly frequency is the input to the daily frequency model; weekly and daily frequencies are input to the time allocation model.
Modeling Skeletal Components of Workers’ Daily Activity Schedules
Authors: Habib Khandker M. Nurul , Miller Eric J.
Published: May 2018

Four sets of econometric models are presented for time use decisions (durations and start times) regarding the basic, regular, and committed components (skeleton) of workers’ daily life: gap before work, work, gap after work, and night sleep. Two types of models are compared for each component: multilevel linear models and continuous-time hazard models. The multilevel models consider three-level random effects (temporal, personal, and household) and the hazard models consider individual-based unobserved heterogeneity. On the basis of performance in fitting observed data, hazard models are selected for the first three components, and a multilevel model is selected for the last component. For parametric hazard models, the Gompertz distribution shows promising performance in fitting activity data. The models are estimated by using 2002–2003 Toronto [Canada] Computerized Household Activity Scheduling Elicitor data.
Households on the Move
Authors: Ampt Elizabeth , Wundke Jessica , Stopher Peter
Published: May 2018

Voluntary travel behavior change has been used in most capital cities of Australia during the past few years. In a new approach, Canberra carried out a pilot test of applying the strategy specifically to households as they undertake a move to a new residence. Households that are moving are in a much more flexible situation to adopt new travel habits. Two primary groups of households were targeted. The first was households that had just moved (i.e., in the past 4 to 6 weeks). The second was households that have committed to a move but have not yet made the physical move. The methods that were used to find and identify households in each of these groups and the success rates of the different approaches are described. Targeting such households poses a number of new issues with respect to the voluntary travel behavior intervention that do not arise in community or suburban applications. A number of these issues are explored in detail and the ways in which these problems have been dealt with in the Canberra project are discussed. One of the key issues is to evaluate whether this intervention is effective. Although evaluation of voluntary travel behavior change is never easy, there are some specific issues that arise with households that are moving or have just moved. The issues relating to evaluation and then the procedures that have been tried in the Canberra case to overcome the problems are described.
Development of Life-Cycle Cost Evaluation Model for Pavements considering Drivers’ Route Choices
Authors: Uchida Kenetsu , Kagaya Seiichi
Published: May 2018

This study proposes a model for evaluating life-cycle cost (LCC) for pavements considering both driver's route choice behavior and repair. It is assumed that drivers change their route choices because of both the change in driving cost brought about by the deterioration of surface conditions on pavements and the change in traffic capacities due to repair work on pavements. The LCC minimization problem is formulated as the implicit program, in which LCC is minimized subject to the probit-based stochastic user equilibrium (PSUE), which expresses drivers’ route choices. The solution algorithm for the LCC minimization problem developed by applying the sensitivity analysis technique for the PSUE is also presented. Last, the simple numerical results obtained by using the test network are shown.
Home–Activity Approach to Multimodal Travel Choice Modeling
Authors: Hoogendoorn-Lanser Sascha , Van Nes Rob , Hoogendoorn Serge P. , Bovy Piet
Published: May 2018

Traditional multimodal travel choice modeling approaches, applicable to single-trip data, distinguish access and egress but make no difference between travelers’ home and activity addresses. It is hypothesized that the differences between home end and activity end with respect to a number of travel-related factors are relevant in the travel choice process and therefore need to be accounted for correctly in multimodal travel choice models. It is shown empirically that differences indeed exist in availability, knowledge, and use of multimodal trip alternatives. In the analysis, revealed-preference data for interurban multimodal train trips in the Netherlands are used. A new home–activity modeling approach is presented: the home end and the activity end are explicitly taken into account in the utility specification, and all attributes are direction free. To illustrate the approach, a generalized nested logit model, suited to capture correlations caused by home-end and activity-end feeder mode types, is applied to the multimodal train trip data. The existence of differences in travelers’ valuation of home-end and activity-end characteristics was found. More specifically, home-end characteristics play a more important role in planning multimodal train trips than activity-end characteristics.
Experimental Measurement of Diversion Due to Ramp Meters
Authors: Wu Jingcheng , Horowitz Alan J. , Hardy Michael S. , Corbin John
Published: May 2018

The effectiveness of ramp meters relates to the availability of alternative freeway or arterial routes, drivers’ propensity to use these alternative routes, and drivers’ willingness to shift trips to alternative times of the day. Ramp metering, which is integral to Southeastern Wisconsin's regional traffic operations program, was evaluated for its effectiveness, including associated diversions of traffic. As part of this larger study, diversion was evaluated by performing a with-and-without meters experiment on a 15-mi corridor of US-45. This evaluation of diversion, primarily through statistical analysis of traffic counts on the freeway mainline, on parallel arterial streets, and at on-ramps along with analysis of origin–destination tables and a survey of Wisconsin drivers, indicates that ramp metering will divert traffic in complex ways. Spatial diversion from the freeway to the alternative routes and from substandard ramps to a more desirable entrance took place within the studied roadway network. Slightly significant temporal variation was found, but the results were difficult to interpret as temporal diversion. Analysis of origin–destination tables showed that there was a reduction in short trips. From the questionnaire responses, it was found that drivers knowledgeable about alternative routes were willing to divert to avoid delays.
Intrahousehold Car-Type Choice for Different Travel Needs
Authors: Petersen Eric , Vovsha Peter
Published: May 2018

A new generation of travel demand models based on individual microsimulation of activities and travel has opened the way for more detailed analysis and modeling of vehicle use. However, the first activity-based models—those applied in practice as well as activity-based model systems developed as research projects—inherited the simplified approach to car allocation and use with no distinction between vehicle types and certainly no explicit modeling of allocation and use of individual vehicles by household members. Structural modeling of car use by vehicle type is essential for air quality and other environmental issues. Further developments of more elaborate policies (toll roads, area pricing, parking restrictions, etc.) that could be differentiated by vehicle size, type, and occupancy are also foreseen. The current study outlines a modeling approach to this issue that can be incorporated into the framework of an operational travel model, as well as reports on the results of estimation for a model of car-type choice based on a comprehensive household survey undertaken in the Atlanta, Georgia, region in 2001.
Demand-Driven Traffic Assignment Problem Based on Travel Time Reliability
Authors: Shao Hu , Lam William H. K. , Meng Qiang , Tam Mei Lam
Published: May 2018

A novel user equilibrium traffic assignment model based on travel time reliability is presented in view of day-to-day demand fluctuation. Because of daily demand variations, path travel times are not constants, and so they can be viewed as random variables. Assuming that travelers are able to learn the variation of path travel time from experience, a demand-driven user equilibrium principle based on travel time reliability is proposed to characterize travelers’ path choice behavior under uncertainty in travel times caused by demand variation. This principle can be formulated as a variational inequality (VI) problem in terms of path flows. The existence of at least one solution for the VI problem, for which a heuristic solution algorithm is adopted, is rigorously proved. Numerical examples are used to illustrate the applications of the proposed model and the solution algorithm.
Theoretical Derivation of Value of Travel Time and Demand Elasticity
Authors: Ozbay Kaan , Yanmaz-Tuzel Ozlem , Holguín-Veras José
Published: May 2018

Users’ value of travel time (VOTT) and their responsiveness to toll changes (elasticity) for different trip purposes in the presence of time-of-day pricing is explored for drivers on the New Jersey Turnpike (NJTPK). An analytical model is developed by extending DeSerpa's classical time allocation model and relaxing the constant marginal utility assumption. This model joins users’ time-of-day choices in the presence of time-of-day pricing and departure- or arrival-time restrictions. With traveler survey data collected to evaluate the NJTPK time-of-day pricing program, VOTT and elasticity functions for different departure-time choices and trip purposes are estimated. The main contribution of the empirical results is the finding that in the presence of time-of-day pricing applications, when the main choice of commuters is departure time rather than alternative routes or modes, VOTT and elasticity of a user are influenced by trip purpose, desired arrival time, and early or late arrival amount in addition to travel time, toll amount, and income parameters. Mean VOTT values range between $15/h and $20/h, and mean elasticities range between —0.06 and —0.18 depending on the departure-time choice and trip purpose. Elasticities calculated from traffic and travel time data reveal estimates that are in the range of —0.15 and —0.31. These relatively high VOTTs and low elasticities from the low traveler response to the minor toll differentials introduced by the New Jersey Turnpike Authority's time-of-day pricing program can have major implications in determining effective toll differentials for future time-of-day pricing implementations in highly urbanized areas, where income levels are relatively high, user flexibility is low, and possibilities to shift to other modes or routes are limited.
Transportation Expenditures and Ability to Pay
Authors: Thakuriah (Vonu) Piyushimita , Liao Yihua
Published: May 2018

Data at several levels of aggregation and spatial resolution show that mobility (measured by different outcomes such as vehicle miles traveled and automobile ownership) increases with income. It is equally likely that, in turn, investments in mobility (purchase and operation of private automobiles, consumption of public transportation services) allow greater quality of life in general and the ability to increase one's income. This possibly circular relationship is explored by using the Consumer Expenditure Survey (CEX) data set. Single-equation Tobit models of annual household transportation expenditures are posited with, in the first case, annual before-tax income and, in the second case, annual total household-level expenditures as a proxy for permanent income. With a variety of demographic, community and spatial, economic, family, and life-cycle conditions of the household controlled, it is found that permanent incomes explain mobility investments better than annual incomes. However, mobility investments and ability to pay are likely to be endogenous since it seems that a greater investment in mobility would lead to positive economic outcomes such as the ability to travel to distant but higher-paying jobs, better and more productive integration of social and household activities into one's work life, and flexibility in job search and ability to change employers to obtain higher wages and benefits without having to make residential location changes. This potential reverse causality is explored by means of a two-stage model in which the censored mobility investment variable and the household's ability to pay are jointly modeled.
Ridership Accuracy and Transit Formula Grants
Authors: Chu Xuehao
Published: May 2018

The accuracy of annual unlinked passenger trips reported to the National Transit Database (NTD) at the agency level is examined by using a two-step approach. The first step compares ridership reported to the American Public Transportation Association (APTA) with ridership reported to NTD. NTD ridership can be as high as 50% more than APTA ridership, and such significant positive deviation exists persistently over time across many agencies. The second step explores potential sources of these deviations by examining their components. Random errors, including both sampling errors and some of the nonsampling errors, do not help explain these one-sided deviations, nor do occasional annual adjustments, such as special-events ridership in the NTD ridership. Much of this deviation appears to be attributable to systematic nonsampling sources that result from undercounting in direct counts, from unintentional biases in procedures, or perhaps from intentional manipulation. Although mechanisms and incentives exist for these sources, there is little evidence for any one specific source. How systematic errors could affect the allocation of two formula grants to Florida transit agencies—the Urbanized Area Formula Grant Program and Florida's Transit Block Grant Program—is quantitatively examined. A strategy for reducing systematic errors is also discussed.
Development of Asset Management Evaluation Framework in Rail Transit Environment
Authors: Adeney William E. , Sinde Asier , Woods Michael
Published: May 2018

In 2003 the London Underground was restructured, and the maintenance and renewal of the infrastructure, both fixed and rolling stock, were contracted to two private-sector consortia for 30 years. At the same time, the position of arbiter was established to oversee these contracts. The development of an asset management evaluation framework for the arbiter is presented. Asset management evaluation from around the world is reviewed, and approaches to measurement applied to such frameworks are discussed. The evaluation framework is explained, and suggestions are made regarding how the work may be developed further. The proposed approach to asset management evaluation is based on existing and recognized approaches to evaluation. It draws out 12 high-level elements that together make up good asset management. For each of these elements a number of key areas and supporting guidance are suggested. The framework also offers extensive guidance based on recognized asset management knowledge. The framework provides a maturity-based approach to evaluation, allowing measurement of asset management proficiency based on knowledge and competent professional judgment. This approach is equally suited to both self-assessment and third-party review, and although it has been developed for a rail transit environment, it could be applied in other sectors.
Allocating Revenues to Public Transit Operators under an Integrated Fare System
Authors: Tsamboulas Dimitrios A. , Antoniou Constantinos
Published: May 2018

A methodology is proposed and a model is developed to address the issue of revenue allocation that arises in most urban public transport systems that implement an integrated fare system and where the transport services are provided by multiple operators. The methodology and models are practical and easy to implement and at the same time scientifically sound, using data collected on a regular basis. The objective for the methodology is to maximize the provided service while introducing incentives to the operators to increase their service quality. The allocation is based on short-term marginal cost. The methodology comprises four components: selection of appropriate performance measures, development of marginal cost factors, data collection and processing, and revenue allocation by using the output of the previous components. The methodology is described in a top-down approach and can be used for the allocation of revenues in a wide range of integrated public transit systems. An application is presented demonstrating the applicability of the methodology and models.
Algorithm for Optimal Bid Packaging for Competitive Contracting in Public Transit
Authors: Chowdhury M. Sabbir U. , Kaysi Isam A. , Shalaby Amer
Published: May 2018

Transit planning has traditionally been approached from the point of view of a single, public operator that dominates transit service provision. Transit market arrangements that encompass a larger potential role for the private sector in providing transit services in a competitive environment have created new opportunities for improved service efficiency and have enhanced operational sustainability. Such evolving market arrangements are bound to necessitate a transformation in the traditional transit planning approaches. Research revisited some transit planning tasks in view of evolving transit market and regulatory arrangements and investigated the implications of one such market arrangement, namely, competitive contracting, for mass transit service design. Competitive tendering elements that relate to determining the size of the contract to be tendered as well as the allocation of routes among bid packages (also known as service design) are addressed. The methodology developed in the research comprises a decision support tool for the planning of transit service tendering, with the modeling framework using a genetic algorithm–based approach to optimal bid packaging. The proposed modeling framework and case study provide a much-needed tool for the analysis of how possible moves to new market arrangements in the transit environment may achieve service sustainability objectives and reduce or eliminate the need for subsidies. The framework is useful for transit authorities wishing to contract out routes in their bus networks.
Lean Manufacturing Techniques in Bus and Rail Maintenance
Authors: Zwas Amy
Published: May 2018

Lean manufacturing techniques save millions of dollars by improving efficiency and reducing waste. Lean principles can be modified for use in the unique environments of bus and rail maintenance. A preliminary investigation of how lean techniques can be employed at the Chicago Transit Authority in Illinois is presented.
Examination of Process of Innovation at Transit Systems
Authors: Hikichi Lynda K. , Beimborn Edward A.
Published: May 2018

A study of the innovation process in transit agencies had two major components. First, case studies of innovations adopted by transit agencies in Wisconsin were conducted. Second, transit agencies across the country were surveyed online to gain a sense of innovation and change. An analysis of the case studies showed that many had common themes and barriers to the various innovations studied. These barriers and themes were funding, the nature of the organization, persistence, the regional planning commission, user involvement, a problem-centered approach, and a champion. The innovations discussed in the case studies came about because there was a need to improve the transit systems, an internal champion, funding, and persistence to overcome barriers to change. Analysis of the survey results revealed that the primary institutional barrier to innovation or change was money, and the main reason for change was an internal leader or champion. Innovation is most likely to occur when there is a need to improve service, when there is a champion to lead and coordinate to bring about the change, and when there is a source of funds for the planning and implementation of the innovation.
Carsharing as Key Contribution to Multimodal and Sustainable Mobility Behavior
Authors: Nobis Claudia
Published: May 2018

Carsharing is just a small niche product on the mobility market. The proven positive effects of carsharing can contribute to solving traffic problems only if the number of carsharing customers grows. A household survey was used to investigate the awareness and the market potential of mobility service carsharing in Germany. The results show that the majority of the respondents do not know what the term “carsharing” means. Even within the subgroup of people who could explain carsharing, local carsharing offers are not well known. To measure the attitudes toward the different modes of transport and acceptance of the general idea to share a car with other people, statement batteries were used. On the basis of factor analyses with linear and logistic regression models, the factors are determined that influence whether a person likes carsharing. Furthermore, the correlation between attitudes and behavioral aspects is revealed. In this context, people with multimodal mobility behavior are found to be more open-minded for shared-use vehicle systems. Finally, by taking subjective (attitudes) and objective (current mobility behavior) criteria into account, the potential of carsharing is estimated.
Carsharing and Station Cars in Asia
Authors: Barth Matthew , Shaheen Susan A. , Fukuda Tuenjai , Fukuda Atsushi
Published: May 2018

In recent years, there has been significant worldwide activity in shared-use vehicle systems (i.e., carsharing and station cars). Much of this activity is taking place in Europe and North America; however, there has also been significant activity in Asia, primarily in Japan and Singapore, with some planned activity in Malaysia. The latest shared-use vehicle system activities in Japan and Singapore are examined, beginning with a historical review followed by an evaluation of their current systems. Overall, there are several well-established systems in Japan (18 systems having approximately 176 vehicles and 3,500 members) and Singapore (four systems having approximately 432 vehicles and 12,200 members). A new program was planned to launch in spring 2006 in Kuala Lumpur, Malaysia, with 10 vehicles. In contrast to most European and North American cities, Japan and Singapore already have a wide range of viable public transportation modes. The primary carsharing focus in Japan is on business use, and in Singapore, on residential–neighborhood use. This likely is because of limited vehicle licensing and high car-ownership costs in Singapore. Further, systems in Japan and Singapore have a high degree of advanced technology in their systems, making the systems easy to use and to manage. The member–vehicle ratios in Asia appear to be approximately the same as in Europe and Canada and less than in the United States. It is expected that Asian shared-use vehicle systems will continue to have steady growth in number of organizations, vehicles, and users.
Bus-and-Rail and All-Bus Transit Systems
Authors: Allen Douglas A. , Hufstedler Gary D.
Published: May 2018

Dallas Area Rapid Transit (DART) in Texas has experienced widely acknowledged success with its light rail system, New Start. Ridership results have met or exceeded expectations. The DART system has experienced significant ridership changes as it transitioned from an all-bus system to a bus-and-rail system. These changes are reflected not only in the growth of light rail ridership but also in changes in bus system ridership. Until the 2004 opening of its light rail line, the Metropolitan Transit Authority of Harris County (Metro) had been a highly successful all-bus transit system. Metro's success with high-occupancy-vehicle lanes supporting an extensive network of express and park-and-ride routes is renowned. Metro's local bus network serves high volumes of passengers daily. These two Texas transit systems have some interesting similarities. Until 1996, both were all-bus systems. Their ridership trends shared general patterns. There are also divergences in ridership patterns occasioned by the differing natures of the two systems. Their service areas are significantly different. Their service area populations, however, are of similar size. Ridership statistics for the two systems as reported in the National Transit Database for 1985 through 2003 are examined. The statistics examined include unlinked passenger trips, passenger miles, and average trip lengths. The changes in these statistics and their comparisons after the inauguration and subsequent expansion of the DART light rail system reflect the changing nature of the DART bus system as its role in the regional transit network refocuses.
Determinants of Perceived Importance of Targeted Transportation Services for Low-Income Riders
Authors: Thakuriah (Vonu) Piyushimita , Sriraj P. S. , Sööt Siim , Liao Yihua
Published: May 2018

It is generally agreed that transit services in disadvantaged neighborhoods can have potentially positive effects on the accessibility of socially excluded or economically marginalized families. The impact of transit services has been quantified by using objective measures, such as travel time, travel cost, and changes in earnings or destinations reached. Although the body of literature on this topic is exhaustive, researchers have acknowledged the importance of more subjective measures associated with trip decision making of individuals. An index of perceived service importance (PSI) was used to study the impact of the subjective dimension of trip making. Riders of transit services were surveyed, and a conceptual model of activity changes that may be enabled by the services of the Job Access Reverse Commute program was designed to facilitate the modeling process. An ordered probit model was developed to explore the relationship between PSI and sociodemographics, service type and characteristics, employment attributes, and travel-related factors. Three models were estimated, and the differences among the models stemmed from the particular subsample used and the effects considered. The results of all three models highlight the importance of the service to frequent users. Time saved, trip length, type of service used, and type of area are somewhat important in explaining PSI, but not in all models. Results indicate that the PSI is indicative of extreme transit dependency, calling for use of these types of measures in addition to hard measures, in evaluating low-income transit services.