bluuebunny/crossref_metadata_2025 huggingface dataset:
Contributions of Heat from Traffic Vehicles to Snow Melting on Roads
Authors: Ishikawa Nobuyoshi , Narita Hideki , Kajiya Yasuhiko
Published: April 2007

The heat balance of road snow was analyzed to examine ice-film formation and to determine the characteristics of heat balance on a natural snow cover. The main heat source used to melt natural snow cover is solar radiation. However, the results of the analysis indicated that the absorbed solar radiation is reduced due to the high albedo of snow and therefore cannot compensate for the heat loss by long-wave radiation. This occurrence results in negative net radiation during winter. To evaluate the heat balance on road snow, the infrared radiation from vehicles was estimated by measuring vehicle temperatures. These measurements indicated that heat input applied to snow decreased with vehicle speed and increased with traffic volume. A new index—the shading time—was developed and is defined as the amount of time a section of road is shadowed by vehicles. It was established that incoming long-wave radiation increased by 50 percent during 20 minutes of shading time and that the net radiation became positive, suggesting that snow melting occurred on roads with heavy traffic flow, even in winter.
Trial Program Study of Dynamic Compaction Earth Work in Taiwan
Authors: Chang Dave Ta-Teh , Chang Jeffery C. I. , Tsai Y. L. , Wang Cheng-Wei
Published: April 2007

A thermal power plant is planned to be built at Taichung Harbor area, and the construction site is located on a hydraulic fill. The medium-to-fine, loose [ N value of the Standard Penetration Test (SPT), < 10] sand deposits on the hydraulic fill will be subject to liquefaction, and because of this, soil improvement is required. Dynamic compaction is thus far considered one of the most appropriate methods used to solve liquefaction, and therefore, a trial program was initiated to obtain ongoing construction details for the whole construction site. The trial area was divided into three sections (Sections A, B, and C) to carry out three different trials. For Section A, the drop weight is 18 Mg, the drop height is 22 m, the grid spacing is 4 m, and the drop number is 8. For Sections B and C, the drop weights are 25 Mg, the drop heights are 25 m, grid spacings are 5 and 6 m, respectively, and drop numbers are 10 and 40, respectively. To achieve a better result in densifying the ground surface, a post-compaction program is introduced into this project before roller compaction is performed. During the post compaction, all trials have drop weights of 13.88 Mg, drop heights of 10 m, and a grid spacing of 2 by 3 m for Section A and a grid spacing of 3 by 3 m for Sections B and C. Results of improvement are expressed as the N value of SPT (SPT- N) and cone resistance, qc. In addition, the excess pore water pressure was also investigated during compaction. Findings indicated that either the SPT- N or the Cone Penetration Test qc improved about 1.5 to 2.0 times. Satisfactory results were also detected for the post compaction. Comparison and analysis showed that the program used for the Section B trial, that is, the trial program with application of medium energy, is the most effective program for use in the whole project. In addition, the soil particle velocity caused by tamping is found to be less than 30 mm/s and will cause no tangible effect on adjacent structures.
Tests for Evaluating Fine Aggregate Particle Shape, Angularity, and Surface Texture
Authors: Hossain M. Shabbir , Parker Frazier , Kandhal Prithvi S.
Published: April 2007

Particle shape, angularity, and surface texture are critical properties in assessing fine aggregate quality for asphalt concrete. The index for aggregate particle shape and texture and uncompacted voids tests indirectly measure these properties. Several sources of fine aggregate from Alabama were evaluated by both tests. Modifications to current test procedures to include all particle sizes normally included in fine aggregate are suggested. Particle index and uncompacted voids are affected by gradation, and this effect should be eliminated in assessing fine aggregate quality. Testing of individual size fractions and computation of composite indexes or void contents or testing of samples with standard gradations are viable options for elimination of gradation effects. Particle indexes or uncompacted voids of blends of two aggregates may be assessed by linear proportioning of values for individual components.
Precisions of Flat and Elongated Particle Tests ASTM D4791 and VDG-40 Videograder
Authors: Prowell Brian D. , Weingart Randy
Published: April 2007

The design procedures for Superpave and stone-matrix asphalt mixtures emphasize the importance of aggregate shape. The current test procedure for characterization of aggregate shape, ASTM D4791, lacks a precision statement and is extremely time-consuming. A round-robin analysis was conducted with 15 laboratories, five materials, and two replicates to determine a precision statement for ASTM D4791. The results from the round-robin analysis, and for two additional materials obtained by the current procedure, were compared with results from the VDG-40 videograder, a promising automated device for measurement of aggregate shape. Although a correlation was indicated, further research is needed to relate the measurements of aggregate shape obtained by both tests to hot-mix asphalt performance.
Development and Potential Use of an Automated Aggregate Gradation Device
Authors: Buchanan M. Shane , Brown E. Ray
Published: April 2007

The determination of aggregate gradation is one important test that is performed during the design, production, and process control in the hot-mix asphalt and the aggregate industries. There is a need for an improved method of gradation analysis in which the gradation determination is accomplished in a more rapid, efficient, and accurate manner. After a review of current automatic gradation technologies, an automated gradation particle size analyzer was selected for further evaluation as a potential automatic gradation device. The automated gradation device performs gradation analysis through an automation of the standard gradation test procedures that are performed in laboratories throughout the country. Extensive evaluation of the device consisted, first, of determination of the optimum sieving time and sample size. Second, because the device is capable only of dry gradation analysis, an evaluation of the ability to use a correction factor to adjust the amount of dust or the percentage of material in the aggregate sample that passes the 0.075-mm sieve was also conducted. The results show that the automated gradation device, with the use of a correction factor, can accurately and precisely determine the gradation of an aggregate sample of approximately 1500 g in 10 min. The use of this device should result in an increased savings in technician and testing time as well as an economic benefit to the user.
Evaluation of Constructing Increased Single-Lift Thicknesses of Unbound Aggregate Bases Case Study in Georgia
Authors: Bueno J. L. , Stokoe K. H. , Allen J. J. , Kalinski M. E.
Published: April 2007

A study was conducted to evaluate the feasibility of compacting unbound aggregate base courses in lifts thicker than those permitted by state departments of transportation (DOTs). At present, the majority of the state DOTs allow a maximum lift thickness of 20.3 cm (8 in.) or less. Work conducted in conjunction with the widening of a state road in Georgia is described. Three test pads of the same base material were constructed and evaluated: one Target Strip and two Test Sections. The Target Strip was placed in two lifts: a 17.8-cm (7-in.) lift followed by a 15.2-cm (6-in.) lift. Each test section was constructed in a single, 33-cm (13-in.) lift. Compaction of the unbound aggregate base courses was evaluated by conventional nuclear density gauge (NDG) testing. Additionally, nondestructive seismic testing was used to evaluate stiffness profiles within the base and supporting subgrade. Spectral-analysis-of-surface-waves (SASW) tests were used for this purpose. Both the NDG and the SASW test results show that a 33-cm (13-in.)-thick layer of unbound aggregate base can be compacted as dense and as stiff as a 15-cm (6-in.)-thick layer. The seismic results also show that the upper 7.6 cm (3 in.) of all three test pads have lower stiffnesses than the bottom 25.4 cm (10 in.). This near-surface layer exhibits a lower stiffness, presumably from lower effective stresses and possibly from some disturbance caused by the compaction equipment. Also, higher moisture contents during compaction of the base yielded lower stiffnesses, even at the same in situ density.
Effects of Drivers' Age on the Comprehension of a Pedestrian Right-of-Way Warning Sign
Authors: Abdulsattar Husham N. , McCoy Patrick T.
Published: April 2007

A survey was done on driver comprehension of a Turning Traffic Must Yield to Pedestrians sign among different drivers' age groups during left-turn and right-turn maneuvers. Four age categories were included: young-young, middle-young, middle-old, and old-old. The sign was comprehended clearly by all age groups for the right-turn scenario. For the left-turn situation, younger drivers (under 56 years) comprehended or paid more attention to the sign than older drivers (over 55 years). This might be due to the difference in the perception of drivers to the presence of pedestrians during left- and right-turn movements. During right-turn movements, drivers and pedestrians always are in interaction, unless drivers are provided with the rarely used exclusive right-turn phase. On the other hand, left-turn movements usually are provided with an exclusive or permitted phase or a combination of both. This might lead to a general perception among drivers that pedestrians are not allowed to cross during a left-turn maneuver and that the driver has the right-of-way. It is recommended that the sign be included in FHWA’s Manual on Uniform Traffic Control Devices.
Identifying Gaps in Child Pedestrian Safety: Comparing What Children Do with What Parents Teach
Authors: MacGregor Carolyn , Smiley Alison , Dunk Wendy
Published: April 2007

Vehicle/pedestrian conflicts are a primary cause of deaths among children age 5 to 12 in North America. Children under 14 are twice as likely as the general population to be involved in vehicle/pedestrian accidents. Parents may overestimate the cognitive abilities of children to handle complex traffic situations and may assume that pedestrian rules taught to children at a young age will help safeguard them when crossing independently. For this reason, parental guidance on crossing safety was compared to actual practice by children, with and without accompanying parents or baby-sitters. Investigations were conducted in Kitchener-Waterloo, Ontario, a midsize, urban community. Interviews were done of a small sample (30) of well-educated parents in the vicinity of facilities used by children. Their responses were compared with observations of children (208) crossing at signalized and nonsignalized intersections in the same areas. While a high proportion of parents, 87 percent, teach safety practices, and 70 percent restate them when crossing with their children, 20 percent do not make unobserved checks of their children. Of those parents who do make unobserved checks, 42 percent found that none of their safety rules were being followed. Observations of children, not necessarily related to the adults interviewed, found that children were less likely to search for traffic at signalized than at nonsignalized intersections ( p < 0.05). At nonsignalized intersections, 33 percent of unaccompanied children performed no visual search before crossing, increasing to 48 percent at signalized intersections. Even smaller numbers (< 6 percent) of unaccompanied children looked behind them for turning vehicles. These findings suggest that, while more research is needed to improve parental training and child response, more emphasis should be placed on responsibilities of drivers and on countermeasures in the traffic environment.
Using License Manuals To Increase Awareness About Pedestrian Hazards at Intersections. Missed Opportunity for Educating Drivers
Authors: Sarkar Sheila , Van Houten Ron , Moffatt John
Published: April 2007

Motor vehicle crashes result in approximately 90,000 pedestrian injuries and 5,000 pedestrian deaths in the United States each year. Of these, 34 percent of the injuries and 18 percent of the deaths occur at intersections. In a recent study, around 5,000 pedestrian-motor vehicle crashes were coded in a population-based sample drawn from California, Florida, Maryland, Minnesota, North Carolina, and Utah. About 1,630 (32.6 percent) of these incidents occurred at intersections, with turning vehicles responsible for 30.4 percent of the incidents and another 15.9 percent due to driver violations. Along with enforcement and engineering, quality education can be very important in improving driver behavior and providing a better understanding of the vulnerability of pedestrians. State driverlicensing manuals can play a key role. Well-written, well-illustrated information on pedestrian conflicts associated with different traffic regulations and controls at intersections and on the potential hazards for pedestrians associated with driver violations, along with statistics, would encourage drivers to modify their behaviors. Better manuals are becoming increasingly important with the gradual phasing out of driver education at schools. The present level of information disseminated by 32 states and the District of Columbia was reviewed and found to be insufficient in these regards, needing significant improvements. Recommendations are offered on ways to improve the quality of information.
Pedestrian Safety in Denmark
Authors: Jensen Søren
Published: April 2007

The number of pedestrian injuries has decreased since the mid-1960s in Denmark. Danish travel surveys show that Danes walk fewer and fewer kilometers; hence, the injury rate for pedestrians has remained almost unchanged since 1980. Results are presented from a comparison study on road safety, modal split, demography, and so forth in 47 Danish cities. A result from the study is that modal choice of the urban population does not correlate with the number of urban road injuries per inhabitant. Combining travel surveys and crash figures points out high-risk road users. New studies are presented on the safety effect for pedestrians of audible warning devices, road lighting, and speed of motorized transport. Lastly, a literature study reviews the effect for pedestrians of 19 safety measures.
Strength of Soft Swiss Lacustrine Clay: Cone Penetration and Triaxial Test Data
Authors: Springman Sarah , Giudici Trausch Jolanda , Michael Heil H. , Heim Robert
Published: April 2007

A new link road is to be constructed top down between parallel cast-in place pile walls under a series of railway lines in Kreuzlingen, Canton Thurgau, which is an important hub in the regional transportation network. The results of a site investigation on the soft, normally consolidated, post-glacial lacustrine clay deposit underlying the railway lines, including a cone penetration test, undisturbed sampling from an adjacent borehole, and laboratory testing, are reported. Strength characteristics of the clay were determined, correlated, and linked to stress history and current stress. The investigation demonstrated a close agreement between strength parameters derived from the laboratory and the in situ testing when a piezocone factor of NkT = 17 was applied. This agreement confirms previous local experience. The results obtained lead to a more differentiated knowledge of the clay deposit, providing valuable data for constitutive modeling. These data will be particularly useful for future local construction work using the observational method and value engineering.
Pore Pressure Dissipation Behavior Surrounding Driven Piles and Cone Penetrometers
Authors: Burns S. E. , Mayne P. W.
Published: April 2007

Driven piles are a common foundation used to support highway bridges. Data gathered from instrumented piles and piezocone tests in finegrained soils indicate that variable pore pressure profiles, which depend on the overconsolidation ratio of the soil, can develop during penetration. For piles driven in soft clays and silts, the pore pressure profiles developed show a monotonically decreasing response with time. However, for piles driven in heavily overconsolidated silts and clays, the pore pressure profiles show dilatory behavior, with the pore pressure behavior increasing from the initial measured value to a maximum, and then decreasing to hydrostatic values. A theoretical framework is presented that combines cavity expansion theory and critical state soil mechanics with an analytical solution to the radical consolidation equation to estimate the pore pressure response as a function of time and to evaluate the coefficient of consolidation of fine-grained soils on the basis of instrumented pile and piezocone data. The method is able to describe the pore pressure response curve in soils that demonstrate either monotonically decreasing or dilatory pore pressure behavior. Driven pile data from three sites are used to verify the estimations of the model.
Evaluation of Pile Capacity Prediction Methods Based on Cone Penetration Testing Using Results from I-15 Load Tests
Authors: Rollins Kyle M. , Miller Nigel P. , Hemenway Daniel
Published: April 2007

Nine axial pile load tests were performed in connection with the reconstruction of I-15 through Salt Lake Valley, Utah. In addition, load test data were collected for seven other piles in the valley. The soil profile at these test sites generally consisted of saturated soft to medium stiff silts and clays underlain by a dense sand bearing stratum at 25 to 30 m. Test piles consisted of closed-end steel pipe piles 300 to 600 mm in diameter with a concrete fill. Because cone penetration soundings were available for 15 of these test piles, these data were used to evaluate the accuracy of five available design methods that are based on cone penetration testing. Methods evaluated were the Dutch, Schmertmann, Tumay, Laboratoire des Ponts et Chaussées (LPC), and Fellenius methods. The Davisson method was used to define ultimate capacity. For most design methods, the estimated skin friction was on average only 40 to 60 percent of the measured resistance. The Dutch method predicted 82 percent of measured skin friction, on average, but still exhibited significant scatter for individual tests. Underprediction of skin friction by the LPC method was caused by unnecessarily severe restrictions for steel piles. Without these restrictions, the standard error was cut in half and estimated capacity was 96 percent of the measured capacity, on average. The LPC method also provided the best match with measured end bearing resistance (within 11 percent on average), whereas other methods overestimated capacity by 60 to 80 percent. Overall, the LPC method without side friction limitations gave 97 percent of the measured capacity on average and had the lowest standard error of any of the methods.
Engineering and Survey-Exchange Standard Engineering Data Format: Standard Engineering Data Format
Authors: Tardy Randall D. , Brown Steve C. , Harmon Mo , Bradshaw Richard W.
Published: April 2007

Data exchange, sharing, and archiving are universal problems for departments of transportation (DOTs) and the consulting industry. Unlike computer-aided design, for which translators have been in place for years, engineering data lack universal standards to enable electronic exchange. The lack of standards means that the civil and transportation engineering data are proprietary. Thus, in most cases, manual transcribing is required to share data from division to division or from department to consultant. In addition, archiving this information puts the DOT at risk of not being able to use this information in the future. A consortium of DOTs, consultants, and vendors was formed in June 1998 to define, document, prototype, and disseminate standard engineering data formats. This nonproprietary file format, Engineering and Survey-Exchange (EAS-E), will enable vendors to provide importing and exporting engines within their proprietary software products that will survive the test of time. EAS-E will foster a more efficient project work flow by DOTs, surveyors, design consultants, owner’s construction staff, and construction contractors. The data of primary interest are horizontal alignments, vertical alignments, coordinate geometry, cross sections, and surface data. Suggested formats for these data are presented.
Development of Integrated Intelligent Transportation Systems
Authors: Smith Brian , Scherer William
Published: April 2007

The development of individual intelligent transportation systems (ITS) that operate well independently is not sufficient to meet the growing transportation needs of urban areas. To realize the true potential of ITS, systems such as freeway management systems, transit scheduling and dispatch systems, signal control systems, emergency computer-aided dispatch systems, and even construction scheduling systems must be integrated to allow for coordinated regional decision making. The formidable task of realizing integrated ITS (IITS) must often be accomplished by various municipal systems, most with little or no automation, and several organizational bodies that attempt to coordinate these efforts into a comprehensive regional network. Each of these organizations and systems has its own set of objectives, and these objectives may be noncommensurate and conflicting. Regional integration allows the systems to share information, allowing transportation officials to manage the entire regional transportation system. A sound regional architecture must be developed to guide developers in fitting their individual systems into a regional context. An overview of a vision of IITS is presented, along with an example of an integrated system proposed for the Hampton Roads region of Virginia. The vision is based on a critical analysis of five principal design areas: regional architecture, open systems, the World Wide Web and extranets, data warehousing, and data mining.
Use of Digital Cameras for Pavement Surface Distress Survey
Authors: Wang Kelvin C. P. , Li Xuyang
Published: April 2007

The categorization and quantification of the type, severity, and extent of surface distress is a primary method for assessing the condition of highway pavements. Several methodologies are reviewed that were developed to automate pavement distress surveys. Existing available applications of automated pavement surface distress surveys rely on analog video technology, which poses several limitations on the performance of the systems. Through the use of new digital, high-performance cameras, high-definition images of pavement surfaces were acquired. These images were directly captured, archived, and analyzed by microcomputers. Two types of digital cameras were used in the research: area scan and line scan. Research revealed that high-performance area scan cameras may have advantages over line scan cameras. However, line scan cameras based on the technique of time delayed integration have good potential when tight synchronization and correct timing control are fully integrated into the system. The imaging subsystem of a full digital highway data vehicle that has been developed at the University of Arkansas is also discussed.
Application of a Utility-Theory-Consistent, System-of-Demand-Equations Approach to Household Travel Choice
Authors: Kockelman Kara
Published: April 2007

By applying a distinct new framework for travel-demand analysis that is based on utility maximization subject to time and money constraints, systems of demand equations are estimated for the underlying determinant of travel demand: out-of-home activity participation. The system of demand equations is derived from a flexible, indirect utility function. For consistency with short-period behavioral observations, the accompanying stochastic specification allows for cardinally ordered integer observations with correlated unobserved heterogeneity. Using 1990 Bay Area Travel Survey data, the parameter estimates of two such specifications are extended to produce estimates of various economic implications, such as values of time and demand elasticities. Several hypotheses regarding travel behavior—including the constancy of travel-time budgets and total activity-participation rates—and the welfare effects generated by changes in the travel environment are also examined.
Effect of Information Quality on Compliance Behavior of Commuters Under Real-Time Traffic Information
Authors: Chen Peter Shen-Te , Srinivasan Karthik K. , Mahmassani Hani S.
Published: April 2007

The compliance behavior of commuters under different advanced traveler information systems (ATIS) information strategies of varying information quality and credibility is investigated. A behavioral experiment involving commuters’ departure time and route decisions in response to traffic information in a simulated traffic system is conducted by using an interactive dynamic multiuser, computer-based simulator. By actually simulating traffic conditions in response to commuter decisions, the simulator provides stimuli to the participants that are always consistent with physically realistic traffic behavior and with their previous decisions. Event-count (frequency) models and dynamic, discrete-choice models are employed to capture the principal effects of the commuters’ experience with the traffic system and with the real-time information on user compliance. The analysis reveals that the information quality of ATIS strongly affects commuters’ compliance behavior. Switching “cost” and recent experience are found to influence their trip-making behavior as well. The analysis further shows that a higher compliance rate can be achieved under prescriptive information than descriptive information. A hierarchy of achievable compliance rates appears to exist in response to the type of information supplied, under which the highest compliance is obtained for reliable, predicted information and the least compliance for random information. Moreover, by providing posttrip feedback with performance information on recommendation or ex–post-best decision, higher compliance is attained.
Vehicle Ownership Model That Incorporates the Causal Structure Underlying Attitudes Toward Vehicle Ownership
Authors: Wu Ge , Yamamoto Toshiyuki , Kitamura Ryuichi
Published: April 2007

Household vehicle ownership behavior is governed not only by economic considerations but also by psychological and sociological factors. The latter factors are expected to play important roles in early stages of motorization. Previous disaggregate models of household vehicle ownership behavior, however, have been developed mostly for countries with mature motorization and most often have included only economic factors as explanatory variables that determine the utility of a household vehicle. These models are limited as models of vehicle ownership behavior in earlier stages of motorization if psychological and sociological factors are, in fact, significant determinants of household vehicle ownership decisions. The concept of symbolic utility of vehicle ownership, which refers to psychological satisfaction from owning and using a vehicle, is considered. Based on analyses of the causal structure among attitudes toward vehicle ownership, a vehicle ownership model system is developed. The results suggest that attitudes toward vehicle ownership have effects on vehicle ownership preference, and the accuracy of vehicle ownership choice models can be improved by taking symbolic utility into consideration. The results of the model estimation also indicate the presence of cognitive dissonance of nonowner households and “Veblen effects” of vehicle ownership.
Analysis of the Role of Traveler Attitudes and Perceptions in Explaining Mode-Choice Behavior
Authors: Kuppam Arun R. , Pendyala Ram M. , Rahman Shela
Published: April 2007

An analysis was carried out using the 1991 wave of the Puget Sound Transportation Panel data set to determine the role played by attitudinal and preference variables in explaining commuter mode-choice behavior. Different modal market segments were compared to determine the extent to which attitudes and preferences differ across mode choices. A factor analysis was performed on the sample to identify a few distinct factors that would summarize the multitude of attitudinal variables present in the data set. Multinomial logit models of mode choice were estimated using different utility specifications. Three types of models were estimated: one that included only demographic variables, another that included only attitudinal factors, and another that included both demographic and attitudinal variables. Likelihood ratio tests were applied to assess the significance of the contribution of different types of variables in explaining mode-choice behavior. Results show that demographic variables and attitudinal variables are extremely important in explaining mode-choice behavior. More noteworthy, however, is the finding that the contribution of attitudinal factors is greater than that of demographic variables, thus emphasizing the need for greater consideration of attitudinal and preference variables in travel-demand-modeling applications.
Application of Poisson Regression Models to Activity Frequency Analysis and Prediction
Authors: Ma June , Goulias Konstadinos G.
Published: April 2007

The Poisson regression model and its variants are used to estimate individuals’ daily activity frequencies by activity type using the first 4 years of the Puget Sound Transportation Panel. The estimated model coefficients are applied to the 5th-year observed data to predict daily activity frequencies by activity type. Forecasting accuracy is measured with indicators of deviation between observed and predicted values. Examples of model estimates and their forecasting performance are provided. Comparisons between the observed and predicted 5th-year data show the predictions to be fairly accurate. Subsistence activity is the most accurate among all types, followed by trip chains, out-of-home leisure, and maintenance activities. The analysis also indicates that different theoretical distributions should be used for different dependent variables.
Time-Quantum Hurdle Model for Activity Type and Duration of Nonworkers
Authors: Misra Rajul
Published: April 2007

Contemporary activity-travel models use a discrete-continuous structure to model activity type and duration. Analysis of raw-activity-traveldiary data shows frequent rounding of start and end times by respondents to multiples of 5 or 10 min. A continuous representation of activity duration in the model could lead to a significant error in estimation that might not always be random. A Poisson process model that uses discrete time to jointly model activity type and duration is presented. It is proposed that a quantum representation of time would possibly provide a more rigorous behavioral interpretation to the individual’s activity choice process. A theoretical description of the time-quantum hurdle model is provided, followed by an estimation of the model for nonworkers in the 1990 Bay Area Travel Survey data set. Also included are an analysis of computational efficiency of the model and possible extensions.
Competing-Risks-Duration Model of Household Vehicle Transactions with Indicators of Changes in Explanatory Variables
Authors: Yamamoto Toshiyuki , Kitamura Ryuichi , Kimura Seiji
Published: April 2007

A household-vehicle-transactions model that was developed as a competing-risks-duration model is presented. The model was developed assuming the following three types of competing risks: ( a) replacing one of the vehicles in the household fleet, ( b) disposing of one vehicle in the fleet, and ( c) acquiring one vehicle to add to the fleet. In addition to the attributes of the household, changes in these attributes are expected to have strong effects on vehicle transaction behavior. To account for their effects, dummy variables indicating the occurrence of a change in selected household attributes were defined as time-varying covariates and introduced into the model. In addition, vehicle transactions themselves change the needs and motivations for vehicle holding, thus affecting the timing and the type of the transaction that immediately follows. Dummy variables indicating the type of the preceding transaction also were introduced as time-varying covariates into the model. The results of the empirical analysis using a data set collected in a panel survey empirically support the theoretical considerations underlying the model development and indicate that the effects of changes in household attributes and that of a preceding transaction are well represented in the model.
Integrated Model System of Stop Generation and Tour Formation for Analysis of Activity and Travel Patterns
Authors: Wen Chieh-Hua , Koppelman Frank S.
Published: April 2007

The implementation of a previously reported conceptual structure for the generation of activity and travel patterns by households and individuals through the formulation and estimation of an integrated model system is described. This integrated model system takes account of interdependencies among travel and activity choices and their structural relationships with exogenous variables. A two-stage structure is employed to model short-range decisions, including the generation of daily maintenance activities (stops); the allocation of stops and automobiles to household members; and the individual’s choice of travel patterns, including selection of the number of tours and the assignment of stops to tours. Multinomial and nested logit models are used to examine the travel and activity choices. The empirical analysis demonstrates a statistically significant linkage between the first-stage choices (the number of household maintenance stops and the allocation of stops and autos to household members) and the second-stage choices (the number of tours and the assignment of stops to tours for each individual). The model system has considerable potential for improving current travel-demand forecasting approaches.
Development of Methods To Estimate Unobserved Link Flows and Their Application to the Amsterdam Orbital Motorway
Authors: van der Zijpp Nanne J. , Bovy Piet H. L. , Schmorak Nora H. J. M. , Bekkers Jos H.
Published: April 2007

To monitor highway network performance, environmental impacts, and congestion levels, highway authorities maintain statistics on traffic volumes. A typical aggregation level of such statistics is 1 h, and a distinction is made between month and type of day. Traffic volumes usually are observed directly for only part of the network. For the remaining part of the network, these time-dependent traffic volumes need to be estimated using time-dependent traffic data and additional static information, such as trip tables. Six estimation methods are discussed. These methods are characterized by the selection of data used, the assumptions on interdependencies between origin-destination (O-D) demands they represent, and their estimation mechanisms. A methodological novelty is in the modeling of the correlation between errors contained in the O-D cells of the prior matrix in case of common departure period, origin, or destination. All methods were verified and analyzed using synthetic data. Experiments with empirical data from the Amsterdam Orbital Motorway show that, for all methods, bias is the main source of error. This problem can be remedied by collecting and using appropriately aggregated data. Experiments also show improved estimation results for methods that take into account a correlated error structure for the prior O-D matrix.
Transferability Analysis of Work-Trip-Distribution Models
Authors: Elmi Abdishakor M. , Badoe Daniel A. , Miller Eric J.
Published: April 2007

An empirical study of the temporal transferability properties of entropy-type trip-distribution models, applied within a fixed geographic region, is presented. Data for the study were drawn from three travel surveys conducted in 1964, 1986, and 1996 in the Toronto region. Very long transfer periods were examined, and a wide variety of model specifications were tested. These specifications ranged from the simple proportional flow model to an occupationally stratified, doubly constrained entropy model, for which spatial separation was measured by highway travel time. These models were estimated using data from 1964 and 1986. The estimated 1964 models were transferred to 1986 and 1996 to predict the distribution of travel. The 1986 models also were transferred to 1996 to predict the distribution of travel. Results showed that the travel-time parameter was not temporally stable. However, pragmatically, the transferred models were found to provide forecasts very comparable to those generated by models estimated in the respective application contexts. Improved model specification consistently resulted in improved precision of the forecasts obtained. In particular, stratification of the data by worker occupation category resulted in models with the best fit to estimation data, as well as forecasts. However, from a decision-oriented perspective, the improvement in precision obtained from additional complexity in specification did not warrant a recommendation for use of more complex models. Thus, the simple, doubly constrained entropy model with spatial separation measured by highway travel time appears satisfactory for use in practical modeling efforts.
Analysis of Travel Cost Components Using Large-Scale, Dynamic Traffic Models
Authors: Palma André , Marchal Fabrice
Published: April 2007

The original departure-time-choice model introduced by W. Vickrey (1969) for a single origin-destination (O-D) pair is used as a framework for analysis. The aggregation of the commuter’s travel cost for large-scale dynamic networks extends the results obtained by Vickrey for the basic single O-D pair model. A test-site application and a policy example (extension of staggered hours) are provided for the network of the city of Geneva, Switzerland. The focus is on the morning peak hour of private transportation networks.
1997-1998 Survey of Potential North American Applications for Emerging Diesel Multiple Unit Technologies
Authors: Pieri Gerald L. , Nelson David O.
Published: April 2007

The results of a survey done in the United States and Canada in 1997 and 1998 are presented. The survey was done to determine the level of interest among current and potential commuter rail operations in applying emerging technologies for self-propelled, diesel multiple unit (DMU) rail passenger cars. Interest in DMU rail passenger cars is waxing across the continent as commuter rail grows in popularity as a transit mode and operators search for possible alternatives to push-pull diesel equipment. The survey team contacted representatives of 58 operators, regional transit agencies, planning agencies, state departments of transportation, and other agencies. Twenty-eight of the respondents currently operate or oversee commuter or regional rail service and 30 do not. The principal survey was conducted in 1997 with follow-on surveys of selected jurisdictions in 1998. Of the 58 potential operators, 19 do not foresee DMU use, 8 currently operate DMUs, 2 are actively implementing DMU plans, and the remaining 29 are considering DMUs for future applications in their jurisdictions. At least 14 potential operators have hosted DMU demonstrations. Two sections are presented: ( a) a summary of findings and observations with a summary table of survey results, and ( b) details on each jurisdiction surveyed covering current operations, plans, and orientation toward DMU applications.
Newark City Subway Overhead Contact System Conversion Project
Authors: Arriojas Josè
Published: April 2007

The New Jersey Transit Corporation (NJ TRANSIT) has contracted with Kinkisharyo to build new, modern light rail transit cars (LRTCs) to replace the aging fleet of President’s Conference Committee (PCC) cars operating on the Newark City Subway. The new LRTCs will draw a significantly higher electrical current than the PCCs. Maximum peak current demand of the LRTCs considered by NJ TRANSIT may exceed 1,200 A, and the existing PCCs draw maximum peak current of about 500 A. To accommodate the higher power demand of the new LRTCs, the existing overhead distribution system was evaluated. Computer simulations of the overhead distribution system indicated that the existing system is not adequate to support the future LRTC operation and that the system needs to be either upgraded or replaced. Two options were evaluated that were capable of delivering sufficient power to the new LRTCs. They were ( a) upgrading the system based on existing feeder/contact wire configuration with larger contact wire and ( b) replacing the existing system with a new two-wire simple catenary system. Finally, investigations were conducted to determine the extent and type of overhead distribution modifications required to accommodate operating the PCCs with pole collectors and LRTCs with pantographs. Design considerations included selecting catenary hardware capable of accommodating the PCC pole-collector operation and easily adapting to pantograph operation to minimize disruption of passenger service.
Dual-Mode Traction Power Distribution for Light Rail Transit: A Design Option
Authors: Boorse Jack W.
Published: April 2007

As light rail transit (LRT) systems continue to develop throughout the United States, the newer extensions tend to have a significant proportion of their alignments physically separated from all street traffic. Where those sections are lengthy, this presents the potential opportunity to use third rail instead of overhead catenary, generally more costly, as a traction power distribution medium. The implications, both positive and negative, of site-selective use of third rail on future systems and extensions are explored. The designs and procedures that allow LRT cars and trains to draw power from both media alternately are discussed, and a method for accomplishing the transition when they remain in motion is described in some detail. Descriptions of some historical and contemporary practices related to the concept are also included. Encouragement is provided for considering the concept as a design alternative for new LRT lines and extensions of existing systems.
Innovative Procurement Methods in Rail Transit Projects: Baltimore’s Turnkey Experience
Authors: Tomeh Osama A. , Schneck Donald C. , Stross R. Andrew
Published: April 2007

The Federal Transit Administration’s (FTA) Turnkey Demonstration Program, as mandated by the Intermodal Surface Transportation Efficiency Act of 1991, is required to select a number of prototype projects for comparison of turnkey to traditional procurement methods. The Baltimore Central Light Rail Line (CLRL) Phase 2 Extensions project is one of four prototype projects currently selected for comparison. In 1992, the Maryland Transit Administration (MTA) started service on Phase 1 of the CLRL project—a 36.2-km-long system with 25 station stops, procured under the traditional method (that is, design/bid/build). The CLRL Phase 2 Extensions project, procured under the turnkey method, completed the 48.3-km plan with three extensions to the original 36.2 km. FTA has requested an evaluation of the effectiveness of the turnkey procurement method in advancing the design, construction, testing, start-up, and initial operation of the CLRL Phase 2 Extensions project. This evaluation effort focuses on the procurement phase of the project. As part of this evaluation, the contractual differences between the conventional contracting method used in Phase 2 and the design/build, or turnkey, contracting mechanisms and incentives that were used in Phase 2 Extensions project are discussed. The focus of this discussion is on the comparative differences of the specific contracting mechanisms and incentives used by MTA in the procurement phase of the two comparable projects, CLRL Phases 1 and 2. This discussion also examines the effectiveness of the procurement approach implemented by MTA as compared with other turnkey contracts.
Washington State Ferries 20-Year Long-Range Plan
Authors: Deardorf Raymond G.
Published: April 2007

The long-range plan of Washington State Ferries is the culmination of several years of effort to develop a 20-year service and investment strategy based on sound transportation data and forecast-model techniques and to incorporate local and regional expectations of ferry service. Components of the plan are set out in a sequence of necessary investments that address current and anticipated terminal and vessel deficiencies. Six new passenger-only vessels, four new vehicle and passenger vessels, and several major new multimodal terminals are included in the plan. Three alternative service strategies were analyzed for each of the four service subareas. From these, a single draft plan was prepared that took into account reasonable assumptions about financial constraints. A thorough public and agency review has resulted in several proposed changes to the plan. These revisions include a reallocation of additional vehicle carrying capacity from an area where there was not consensus on the solution to areas where there was consensus that the draft plan was deficient. The final plan identifies several major strategies for the four major geographical subareas within the ferry system’s service area to accommodate the projected increase in traffic growth and is balanced within likely farebox and tax revenue constraints.
Intermodal Ferry Terminal Master Plans for Washington State Ferries: Planning for the Future
Authors: East Russell S. , Armstrong Eugene V.
Published: April 2007

The Washington State Ferries (WSF) system has grown tremendously since its ferry terminals were constructed more than 40 years ago. Vehicle traffic is at capacity, and future plans must maximize intermodal transfers of passengers from transit to ferries. WSF has completed master plans addressing this issue at six ferry terminals. The master plans for Anacortes and Bainbridge Island are addressed, and each has unique conditions. Bainbridge is a commuter terminal, has the system’s largest traffic volumes, and is planned for 218-car, 2,500-passenger vessels operating on 35-min average headways. Anacortes, a tourist-driven facility, serves one international and four domestic routes. Although physically the largest terminal, it is also the most remote and has the longest waits. The primary methodology for planning ferry terminals is to separate travel modes for safe and efficient travel and to minimize intermodal transfer time. Direct links are needed for passengers from public transit and rail systems to ferries. Each terminal accomplishes this with similar, but unique, site-adapted solutions. Each terminal is planned using data developed for the project. Compliance with the Americans with Disabilities Act is analyzed using special programs. Passenger counts and growth curves are developed from WSF’s systemwide planning and processed to predict future modal splits. Fast, efficient, safe ferry terminals must separate modes of travel. Passengers must be able to transfer between travel modes with minimal time. Over-water coverage and environmental regulations offer challenges unique to ferry terminals. For success, each ferry terminal master plan must address these issues.