bluuebunny/crossref_metadata_2025 huggingface dataset:
Design and Construction of Smart Road over Wilson Creek: Montgomery County, Virginia
Authors: Kohls Amy R.
Published: April 2007

The Smart Road over Wilson Creek, located in Montgomery County, Virginia, is the primary bridge project on a future four-lane divided roadway between Blacksburg, Virginia, and Interstate 81. The road was given the name Smart because it will be used as a test bed for research in such areas as variable weather and lighting conditions, communications systems, and experimental pavements. Figg Bridge Engineers, Inc., designed the bridge for the Virginia Department of Transportation (Virginia DOT) and provided construction engineering and inspection services on site. Aesthetics were a major concern for the Virginia DOT and the local community because of the natural beauty of the surroundings. Long spans were used to minimize the number of piers. The 605-m five-span structure has three interior spans of 144 m (472 ft) and end spans of 86.5 m (284 ft). The variable-depth concrete box girder superstructure was built by using cast-in-place balanced cantilever segmental construction with form travelers. The cast-in-place piers are conventionally reinforced voided rectangular sections with variable slopes in both directions. With pier heights varying up to 41.4 m (135 ft), the bridge deck is a maximum of approximately 53 m (175 ft) above the valley floor, making the Smart Road the tallest bridge in Virginia. Other aesthetic enhancements implemented on this project include monolithic connections between the piers and the superstructure, the use of natural stone treatments on the piers and railing terminal walls, an open bridge railing, and a concrete surface coating.
High-Performance Steel Cost Comparison Study
Authors: Horton Richard , Power Edward , Van Ooyen Kristi , Azizinamini Atorod
Published: April 2007

In 1996, the American Iron and Steel Institute, the Office of Naval Research, and the FHWA introduced new high-performance steel (HPS) grades with superior strength, weldability, and toughness. Since then, HPS-70W has been used successfully on bridges across the country and is increasingly gaining popularity with bridge design professionals. As HPS-70W steel becomes a more viable alternative, designers are faced with two basic questions: When is HPS-70W steel economical? What are the advantages of its use? To determine the economy of HPS-70W steel, a study was conducted to compare the relative cost of steel designs using HPS-70W and conventional-grade 50W. Investigated were the conditions in which HPS-70W steel would offer economic advantages over grade 50W steel as well as its other advantages. The study considered three two-span continuous bridge arrangements with 45.75-m (150-ft), 61-m (200-ft), and 76.25-m (250-ft) span lengths. Variable bridge cross sections were considered with 2.75-m (9-ft) and 3.66-m (12-ft) girder spacing. Forty-two girder designs were developed and compared for weight and cost and submitted to fabricators across the country to obtain relative costs. From these data, cost comparisons of designs using HPS-70W steel and conventional-grade 50W steel were derived. Guidelines were also developed to aid bridge designers in evaluating the economical use of HPS-70W steel and various hybrid combinations and gain the advantages of HPS-70W steel through its efficient use in design.
Grouted Connection Tests in Development of Precast Bent Cap System
Authors: Matsumoto Eric E. , Kreger Michael E. , Waggoner Mark C. , Sumen Guclu
Published: April 2007

Tests were conducted as part of the first two phases of a research project that developed a design methodology, construction guidelines, and design details for connecting precast concrete bent caps to cast-in-place columns or precast concrete trestle piles in nonseismic regions. Three types of precast connections were addressed: grout pockets, grouted ducts, and bolted connections. The first phase of testing included 32 pullout tests of epoxycoated straight and headed bars embedded in a grout pocket or grouted duct. The yield strength of the bars was developed in grouted connections at an embedment depth of 13 bar diameters or less. Pullout capacity of single- and multiple-headed bars in grout pockets was predicted closely by the concrete capacity design method equations modified by a cracking factor of 0.75 to account for grout-pocket cracking. A development length equation based on a uniform bond stress model was derived for anchorage of straight bars in grouted ducts. The second phase of testing included a full-scale bent cap-to-column connection test for each connection type. Specimens in these proof tests exhibited minor levels of cracking and connector strain in the connection region at factored levels. Failure tests demonstrated adequate connector anchorage, large connector ductility, and negligible influence of shims and the grout bedding layer on response. Results from Phase 1 and Phase 2 tests were used to develop anchorage design provisions that are incorporated in the complete design methodology.
Experimental and Numerical Response of a 1915 Riveted Through-Girder Bridge
Authors: Linzell Daniel G. , Nevling Deanna L. , Kollias Adrian A. , Laman Jeffrey A.
Published: April 2007

Chester County Bridge #21, a 16.5-m (54-ft), single-span, riveted, through-girder bridge located in upper Oxford Township, Pennsylvania, was field tested to determine the response to controlled loading. The bridge was instrumented with strain and displacement transducers to monitor response at critical locations as a single-axle truck of known weight was driven across the structure at crawl and posted speeds. Strains generated in the girders and in transverse floor beams supporting the deck were measured along with girder midspan vertical deflections. Information produced from the tests was used to ( a) assess the level of composite action and load distribution in the structure and ( b) determine if certain members are reaching critical stress levels and to determine the load rating. In addition, analytical models were developed both to predict the response and to evaluate the level of calibration required to establish a model that accurately reflected measured response.
Numerical Load Rating of Reinforced Concrete Compression Members: Demonstration with Connecticut Arch Bridges
Authors: Ranasinghe Arjuna P. , Gottshall Wendy L.
Published: April 2007

As the reinforced concrete arches and columns built over a century ago begin to deteriorate, the load rating of these structures becomes increasingly important because decisions about bridge rehabilitation, replacement, and capacity are based on the value of the load rating. Compression members can be load rated to determine the effect of their structural condition on their live-load carrying capacity. Methods for the analysis of compression members based on the formulation of an interaction diagram are useful for the design of compression members but have theoretical and analytical limitations in their use for load rating. After a survey of the theory and inadequacies of this solution for load rating, procedures for analysis of compression members were developed that can be efficiently and accurately applied to load rating. This load-rating technique is combined with a standard structural analysis tool and a spreadsheet application for efficient rating of all compression members in a standardized format. As demonstration, the method was applied to load rating of the Bulkeley Arch Bridge in Hartford, Connecticut, which carries I-84 over the Connecticut River, and of the Housatonic Bridge in Milford, Connecticut, which carries US-1 over the Housatonic River. The technique used to rate these bridges was generalized for a wide variety of compression members, including those in biaxial bending, slender columns, and members with deterioration, using both load factor design and load and resistance factor design. Only with a proper understanding of our bridges gained through a standardized method of rating can their safety, function, and form be maintained.
Stress-Rupture Performance of Glass-Fiber Reinforced Composites
Authors: Greenwood Mark E.
Published: April 2007

A new family of materials is available to address the issue of premature failure of reinforced concrete structures as a result of rusting of steel reinforcements. Composite reinforcing bars have been recognized by the American Concrete Institute as an acceptable alternative to steel and epoxy-coated steel rebars for use in reinforced concrete structures. An initial study was conducted to quantify stress limits for one class of composite rebars to assess their capability to provide 50 years of service. Stress-rupture testing was conducted to assess the combined effects of constant stress and a concrete environment on the life of pultruded composite rods. The results provide proof of concept that glass-fiber reinforced composite bars can provide long-term performance as a reinforcement system for concrete structures.
Model Specification for Composites for Civil Engineering Structures
Authors: Bank Lawrence C. , Gentry T. Russell , Thompson Benjamin P. , Russell Jeffrey S.
Published: April 2007

A model specification for fiber-reinforced polymer (FRP) composite materials for use in civil engineering structural systems was developed. The model specification provides a classification system for FRP materials, describes admissible constituent materials, and specifies limits on selected constituent volumes. The specification provides procedures for qualifying FRP composite laminates and for accepting FRP composite parts constructed of qualified laminates. Test methods to obtain mechanical and physical properties were devised, along with stipulation of limiting values for selected properties for both laminates and parts. Based on the Arrhenius model, a protocol was outlined for predicting long-term property values subjected to accelerated aging.
Composite Action in Steel Girder Bridge Superstructures Subjected to Transverse Earthquake Loading
Authors: Carden Lyle P. , Itani Ahmad M. , Buckle Ian G.
Published: April 2007

Experiments are being performed on a 0.4 scale model of a steel girder bridge superstructure with a reinforced concrete deck to investigate means of improving the seismic performance of typical slab and girder bridges. During the early stages of experimentation, the need to understand the influence of composite action became apparent. Accordingly, an analytical study was undertaken. The first of several finite element analyses on a typical continuous four-span, four-girder bridge model assumed shear studs along the entire length of the bridge to provide full composite action. A second model omitted the shear connectors in the negative moment regions, a common design practice to avoid fatigue concerns in the top flange. It was found that the shear connectors in the fully composite model were sufficient to ensure composite action when subjected to transverse loading and provided an adequate load path through the superstructure and into the substructure. However, the lack of shear connectors in the negative moment regions caused the load to be transferred into the steel girders at the points of contraflexure, resulting in damage to these girders and inadequate formation of the ultimate limit state in the columns. The lack of composite action was also found to change the distribution of transverse shear forces in the cross frames, which is important for design of the end cross frames. Making the top chord of the cross frames composite with the deck, at the column bent locations, proved effective in minimizing damage to the superstructure.
Hybridizing with Engine Power Reduction
Authors: Santini Danilo J. , Vyas Anant D. , Anderson John L. , An Feng
Published: April 2007

Although many studies that use vehicle simulation models to estimate fuel economy gains for a range of hybrid vehicles have attempted to control for the comparability of performance between conventional and hybrid vehicles, different rules and simulation models have been used. The fuel economy gain estimates versus performance change for a set of those studies are reviewed, and causes for the wide range in estimates of fuel economy gain when hybridizing a gasoline-fueled vehicle are examined. Data are compiled, and relationships are discussed in detail for 18 cases: three studies of four or more cases each. The data are used to develop statistical models to evaluate the causes of variation in fuel economy gain within and across the studies. Three studies (each evaluating one case only) that predict lower fuel economy gains than the first three are also examined. Explanations and adjustments are provided to illustrate that the differences across the studies are less than a cursory reading would imply. Most notably, potential fuel economy gain via hybridization increases as the 0-to-60-mph times of the compared vehicle pairs drop (and power-toweight ratios increase). Also a reduction in engine power is necessary to obtain large benefits. The most complex statistical model developed indicates that an increase in electric motor power relative to engine power improves the fuel economy of hybrids, up to a point. Finally, results indicate that continuous top-speed and grade-climbing ability will drop if a less powerful engine is used.
How Much Can Vehicle Emissions Be Reduced?: Exploratory Analysis of an Upper Boundary Using an Emissions-Optimized Trip Assignment
Authors: Sugawara Satoshi , Niemeier D. A.
Published: April 2007

The development of a trip-assignment model designed to systematically compute emissions-optimized traffic flows for carbon monoxide is explored. Then the exploratory theoretical emissions-optimized tripassignment model is used to estimate the maximum carbon monoxide emissions reductions under varying congestion levels on a hypothetical network. The experimental results indicate moderate reductions in system-level vehicle emissions under emissions-optimized trip assignment compared with the conventional time-dependent user-equilibrium and system-optimized models. They suggest a possible method for approximating an upper boundary of expected emissions reductions using the standard travel-demand model with a modified trip-assignment objective function. The approximate boundary is useful as an estimate of emissions reductions that might be possible under optimal conditions (e.g., drivers choose emissions-optimized routes, fully implemented intelligent transportation systems, etc.). In other words, the upper boundary suggests that current traffic optimization strategies may be insufficient to fully remedy air quality problems created by mobile-source emissions.
Estimating Air Pollutant Reduction Credits for Alternative-Fuel Vehicles with AirCred
Authors: Saricks Christopher L.
Published: April 2007

Primarily to assist the U.S. Department of Energy’s Clean Cities coalitions in estimating the net benefits of reducing air pollutant emissions gained by acquiring original equipment manufacture (OEM) alternativefuel vehicles (AFVs), Argonne National Laboratory has developed a graphical user interface-based benefit calculation model called AirCred. The application of this modeling tool has been extended to the estimation of state implementation plan credits for AFVs that may be claimed in nonattainment and maintenance regions for ozone and carbon monoxide. The tool also has been approved for and applied to the quantification of projected program benefits in applications for grant support to purchase OEM AFVs under the U.S. Department of Transportation’s Congestion Mitigation and Air Quality Program. First, the model’s founding principles and relatively simple mechanics are presented, accompanied by graphic displays of data input screens and comparative results for various vehicular categories. Current and future plans are cited for enhancement of the tool, including its respecification for consistency with MOBILE6 and for air planning in the yet-to-be-designated nonattainment areas for ambient particulate matter of 2.5 μm and smaller. Then some issues and controversies about how and where AirCred should be applied are chronicled. Finally, some example applications are presented to illustrate the residual benefits of AFVs over time relative to their conventionally fueled counterparts of the same (recent) model year. Results indicate that AFVs of certain categories will remain viable and attractive candidates for reducing air emissions in ozone and carbon monoxide air quality control regions well into the future.
Effect of County-Level Income on Vehicle Age Distribution and Emissions
Authors: Miller Terry L. , Davis Wayne T. , Reed Gregory D. , Doraiswamy Prakash , Tang Anna
Published: April 2007

In conjunction with a statewide emissions inventory of on-road mobile sources in Tennessee, a county-by-county analysis of vehicle registration data was performed. Several interesting trends were observed in the kinds and ages of vehicles driven in Tennessee counties compared with national statistics and compared with the average personal income of county residents. In particular, median vehicle age correlated strongly with average personal income for each county. Vehicle fleets were oldest in lowestincome counties and newest in the highest-income county; median vehicle age was 10.8 years in the former and only 5.9 years in the latter. This difference in vehicle age results in average mobile-source emissions factors 63% higher for nitrogen oxides, 73% higher for carbon monoxide, and 104% higher for volatile organic compounds in the lowest-income counties than in the highest-income counties, based on the MOBILE6 emissions model run for calendar year 2000. The low-income counties also registered 76% more light-duty trucks per capita than the national average, and these trucks were 5 years older than the national median age. It is concluded that county-level personal income is a good predictor of vehicle age and can be used as a readily obtainable indication of whether local vehicle registration data should be used to improve the accuracy of emissions inventories (instead of national defaults or statewide averages). County-level personal income also can be used as a basis for determining whether more than one vehicle age distribution should be used for modeling mobile-source emissions within a state, a metropolitan area, or an airshed.
Environmental Effects of Various Modes of Passenger Transportation: Comprehensive Case-by-Case Study
Authors: Wacker Manfred , Schmid Volker
Published: April 2007

One important strategy for reducing energy consumption and harmful emissions involves shifting transportation demand from private to public modes. Calculations of average emission units (based on traffic performance) promise to improve the status quo. However, on closer examination of individual transportation demands, these calculations prove faulty in some areas. In traveling from point A to point B, an individuals' energy consumption and emissions vary based on the choice of mode of transportation, pre-and posttrip travel, and different capacity use and energy sources of vehicles. All these aspects are taken into consideration in a newly developed methodology, and their effects on primary energy use and emissions are analyzed for different transportation modes. During actual trips, energy consumption and emissions are precisely calculated, taking into account not only the operating conditions of the vehicles but also the construction and maintenance of the roads and railways as well as vehicle production, maintenance, and disposal. This new method enables a more precise examination of typical planning tasks. To this end, transportation needs for peak-hour, shopping, and leisure traffic are investigated. Urban as well as interurban and rural routes are examined. The results show the impact of the different parameters to be considered in the calculations. For this reason it is necessary to consider all these influences in every particular case instead of adopting general opinions.
Estimating Air Quality and Congestion Relief Benefits of Commuter Choice Programs with the COMMUTER Model
Authors: Herzog Erik , Hall John M. , Carlson Thomas
Published: April 2007

One key impediment to promoting transportation demand management (TDM) programs as measures to improve air quality has been the dif- ficulty in quantifying benefits—specifically, the lack of quantification tools accessible to the nonspecialists who are responsible for implementing TDM programs in local government and in workplaces. To address this issue, the Environmental Protection Agency (EPA), supported by Sierra Research, Inc., developed a user-friendly spreadsheet-based model called COMMUTER to calculate the travel and air quality benefits of programs that encourage commuter travel modes other than solo driving. The model assesses the benefits of measures that provide information about and encouragement to use alternative modes other than in-vehicle travel time for automotive modes. Hence COMMUTER does not estimate roadway pricing, the impacts of roadway expansions, signalization improvements, and the like. It uses a pivot-point method to estimate changes in trips and vehicle miles of travel from baseline conditions and a lookup table of emissions factors from EPA’s MOBILE model to estimate the resulting emissions changes. The model uses key shortcuts in the amount of data used and the number of microlevel calculations performed to judiciously trade off some accuracy for a significant increase in ease of use. Regional analyses can be performed on programs covering defined subregions within an urban area, such as a central business district or a highly traveled corridor. Site-specific analyses enable benefits to be projected for programs at individual work sites.
Multiyear Pavement Repair Scheduling Optimization by Preconstrained Genetic Algorithm
Authors: Tack Joseph N. , J. Chou Eddie Y. J.
Published: April 2007

Development of a genetic algorithm (GA)–based optimization tool for determining the optimal multiyear pavement repair schedule is described. The problem of finding the best multiyear work plan can be modeled as a combinatorial optimization problem, the objective of which is to achieve the highest possible average network condition for a given budget and operating constraints. Two GAs and a dynamic programming (DP) approach were implemented to determine multiyear repair schedules. The DP method resulted in optimal solutions, but it suffers from rigidity and inability to handle large-scale problems. The GA techniques obtained solutions that were near optimal and maintained flexibility and scalability. The GAs implemented were of two types: simple and preconstrained. The simple GA uses constraints when searching for solutions. The preconstrained GA uses constraints that limit which repair can be selected before searching for solutions to attain better efficiency.
Maryland State Highway Administration’s Project Selection Process: Integrating Network and Project-Level Analysis
Authors: Stephanos Peter , Dorsey Paul , Hedfi Adel
Published: April 2007

The Maryland State Highway Administration (SHA) is responsible for maintaining a 16,000-lane-mi pavement network. To maintain this network Maryland SHA prepares a system preservation program annually that includes specific roadway locations to be improved. In recent years, the process to develop this program has improved considerably through the development of new pavement management tools. These tools have provided Maryland SHA the ability to evaluate multiple funding strategies to invest in the pavement network and the consequences, with regard to network health, for implementing the strategies. In addition, the development of new tools has provided a methodology to identify and select specific project locations for funding in an easier and more accurate manner. The implementation of two of these tools is discussed. These tools include an optimization process to create funding strategies and a computerized project selection tool to identify specific project locations. The approach to using each of these tools in Maryland is described. The report includes discussion on how investment strategies are developed and approved, how projects are selected to match the investment strategy, and how modifications are made to the plan throughout the year. Planned efforts to enhance the process in the future are discussed as well as conclusions on the implementation to date.
Risk-Based Life-Cycle Cost Analysis for Project-Level Pavement Management
Authors: Reigle Jennifer A. , Zaniewski John P.
Published: April 2007

Life-cycle cost analysis (LCCA) is a decision-making tool that highway agencies may use in selecting an optimal pavement preservation strategy. Traditionally, LCCA models for pavement management use discrete input values that represent a conservative best guess of each parameter. Thus, inherent uncertainty associated with each input parameter is not considered. The model developed for this research is probabilistic and derives flexible pavement designs, generates preservation strategies, and evaluates the life-cycle costs of each alternative. Risk analysis is incorporated into the LCCA model so that the inherent uncertainty of each input parameter is considered. Other features of the model include the incorporation of functional aspects (structural capacity and pavement condition) and safety (skid resistance) into the design, the inclusion of rehabilitation and preventive maintenance as preservation strategy alternatives, and the consideration of both agency and user costs in the present-worth cost analysis. The LCCA model output consists of probability distributions that describe the total present-worth cost, the agency present-worth cost, and the user present-worth cost for each preservation strategy over a specified analysis period. The probabilistic nature of this LCCA model exposes areas of uncertainty that may be hidden in a deterministic LCCA model and allows the decision maker to assess the risk associated with each preservation strategy. Finally, a sensitivity analysis was performed to assess the effects of various input parameters on model output. The highway agency can enhance the model output by focusing more detailed data collection and parameter estimation on the model components that were identified as having a statistically significant effect on the model results.
Framework and Strategy for Implementing an Information Technology-Based Pavement Management System
Authors: Tsai Yichang James , Lai James S.
Published: April 2007

The advent of information and telecommunication technologies has had significant effects on the development and implementation of pavement management systems (PMSs) for state departments of transportation (DOTs) and also fosters great opportunities for improving states' highway pavement conditions through increased productivity and effectiveness in managing their highway pavement information. However, it still remains a challenge for state DOTs to successfully implement an integrated PMS due to the complexity of PMS and many issues involved in the development and implementation that need to be resolved. The development and implementation of an information technology (IT)-based PMS by the Georgia Department of Transportation is presented. On the basis of existing pavement management practices by Georgia DOT, the needs and concerns for improvements are identified in light of the advent of IT. The development of the conceptual IT-based PMS framework to meet Georgia DOT’s needs is first presented. The strategies for developing and implementing an integrated PMS are then presented, and the benefits of adopting the strategies are discussed. The need for incorporating a common spatial and temporal reference system to ensure system compatibility and integration for all the databases is discussed. Seven modules of this integrated IT-based PMS have been implemented, including the computerized pavement condition evaluation system, historical pavement performance data conversion and filtering system, network-level data management and analysis system, geographic information system analysis and visualization system, rehabilitation treatment decision system, highway maintenance management system, and the knowledge-based system for diagnosing pavement distress causes. Four modules currently under development are also described.
Cumulative Traffic Prediction Method for Long-Term Pavement Performance Models
Authors: Byrum Christopher R. , Kohn Starr D.
Published: April 2007

A method used to develop predictive models for estimating cumulative traffic volumes for FHWA Long-Term Pavement Performance (LTPP) test sections is presented. The purpose of developing cumulative traffic prediction models for each LTPP site is so that distress and roughness development can be compared with cumulative traffic volumes for the various pavement types and conditions in the LTPP study. There are two types of LTPP traffic data: historical estimates and monitoring data. Predictive models from this study are based on the combined monitoring and historical LTPP traffic data available in January 2000 and designated Level E data. The models attempt to predict the cumulative kilo-equivalent single-axle loads for the LTPP test sections corresponding to any profiling date or distress survey date. The modeling method is described and consists of fitting an exponential growth curve to each site’s data. As a result of the high variability of the LTPP traffic data and some apparent errors in the data, considerable judgment in the form of deleting and changing the reported LTPP data was required before the modeling process. Examples of reported versus backpredicted traffic curves are presented for various traffic conditions encountered. Some differences in historical and monitoring traffic data are shown. Some trends in the traffic data that affect the fitting of exponential growth-type predictive models to the data are described. Methods used to address these trends during model development are discussed.
Identification of Pavement Failure Mechanisms at FHWA Accelerated Loading Facility Ultrathin Whitetopping Project
Authors: Rasmussen Robert Otto , McCullough B. Frank , Ruiz J. Mauricio , Mack James , Sherwood James A.
Published: April 2007

In 1998 eight test lanes of ultrathin whitetopping (UTW) were constructed over existing hot-mix asphalt (HMA) pavements at FHWA’s Accelerated Loading Facility (ALF) located at the Turner-Fairbank Highway Research Center in McLean, Virginia. Various combinations of thicknesses, joint spacings, fiber reinforcement, and types of HMA base were used. In spring 2000 the loading experiment of these pavements was completed, and the analysis of behavior and performance was begun. A summary of some of the pavement distresses observed at the ALF is presented, and hypothesized failure mechanisms are identified, providing an addition to the state of the knowledge with respect to the actual life cycle of UTW pavements.
Evaluation of Past Audits of Project Development on California State Highway System
Authors: Hecht Harry , Niemeier Debbie
Published: April 2007

The California Department of Transportation (Caltrans) is responsible for developing and maintaining the state highway system. Fourteen audits related to the Caltrans project delivery process have been conducted in the last 30 years, an average of about one every 2 years. Most of the audits cited expense and timeliness problems with project development. Yet neither the degree to which these audits accurately assessed the problems with project development nor the degree to which implementation of audit recommendations served to improve project development has been evaluated. The audit findings and recommendations were researched and compared with newly collected data from interviews with project managers involved in the development of highway projects throughout California. Findings indicate that many of the recommendations of past audits have not been implemented, do not apply, or, if implemented, do not appear to have materially changed or to have improved project development times or costs. A flaw of previous audits was the failure to directly involve project managers in identifying constraints on project development. Moreover, discussions with project managers suggest there is a need to update, review, and value-engineer an overly rigid project development process. Despite audit assertions that project delivery can be improved with more aggressive project management, project managers are not delegated the same level of authority as they are assigned responsibility. Thus, the role of the project manager in project planning, management, and quality control is administratively constrained. There is a need to develop new methods for conducting these types of audits so that major issues and problems are better defined before solutions are recommended.
New Jersey’s Capital Investment Strategy: Case Study of Performance-Based Programming
Authors: Stout Mark L.
Published: April 2007

Capital investment strategy is a term used by the New Jersey Department of Transportation (NJDOT) for a set of performance-based programming tools, including goals, objectives, performance measures, and alternative investment scenarios. Performance-based programming was first tried by NJDOT in the 1989 long-range transportation plan. Performance measures and benchmark investment targets were assigned to program categories within expected resources over a 5-year period. This approach was updated and expanded beginning in 1996 as part of a redesign of NJDOT’s planning and programming processes. In 1998 a detailed capital investment strategy was linked to the governor’s “vision plan,” including goals and objectives for a 12-year period. Some of these objectives had performance measures related to system condition (outcomes), and others had simpler performance measures. In 2000 the legislature enacted a state trust fund reauthorization bill that required NJDOT to submit an annual capital investment strategy report as a companion document to the annual proposed capital program. The act also set out several specific goals that were to be included in the report. The March 1, 2001, capital investment strategy report, which concluded that some of these goals were not feasible, led to a lawsuit by transportation advocacy groups, which was later dismissed.
Integrating Visualization into Structured Public Involvement: Case Study of Highway Improvement in Central Kentucky
Authors: Bailey Keiron , Brumm Joel , Grossardt Ted
Published: April 2007

Public involvement in transportation infrastructure decision making is frequently mandated and is regarded as increasingly essential by a wide variety of stakeholders. The integration of advanced technologies, such as visualization, into this process is increasingly desired. However, public involvement processes often are regarded as problematic by many stakeholders and the state highway agencies charged with implementing them. Structured public involvement (SPI) is posited. SPI takes a systems approach toward the integration of advanced technologies into public involvement forums. Because the goal of public involvement is to increase user satisfaction with both the process and the outcomes, the characteristics of advanced technologies and their capacities for gathering useful feedback in public forums must be evaluated. Visualization is put forth as an enabling technology within an SPI framework. The properties, capacities, and transportation-related uses of three visualization modes are evaluated, and their operational features are discussed. A case study dealing with highway improvement in central Kentucky reveals that three-dimensional renderings are significantly preferred to twodimensional and virtual reality modes; the case study also shows that visualization should complement, not replace, other performance information. The role of electronic scoring as an integral component of this SPI protocol is emphasized, resulting in fast assessment and free expression of views. Factors affecting the efficiency of visualization are analyzed, and recommendations are presented for implementing SPI protocols that rely on visualization. These include investigating participants' previous experience with visualization, incorporating iterative public involvement in finalizing design options, and ensuring that the technologies are compatible with the chosen public involvement process.
Model-Based Long-Range Transportation Planning Tool for New Jersey
Authors: De John Anthony J. , Miller Robert , Winslow Kyle B. , Grenier Jennifer J. , Cano Deborah A.
Published: April 2007

The New Jersey Department of Transportation (NJDOT) updates its long-range transportation plan every 5 years. The plan sets forth strategies, provides a framework for directing investment, and identifies financial resources needed to sustain the plan’s vision. Setting the direction of a long-range transportation program revolves around forecasting future transportation conditions and managing investments to address future needs. An analysis tool was needed to help assess the impact of growth on the statewide transportation system and predict system performance based on multimodal strategic investments. The development and use of an analysis tool based on a travel demand model to assess congestion and mobility issues in 2025 are described. The analysis tool linked the state’s three metropolitan planning organization (MPO) regional travel demand models to perform a statewide assessment. Although the models were run independently, methods were developed to provide a common basis for forecasting future travel conditions. The models used MPO-generated trend-based growth in population and employment through 2025. Multimodal transportation supply and demand strategies, including transit improvements, capacity improvements, transportation demand management strategies, and intelligent transportation systems-transportation system management strategies, were simulated and tested to assess what types and combinations of improvements would be needed to relieve congestion and improve mobility. The tool proved very helpful in defining transportation needs and providing input to a financial assessment. The testing indicated that no single strategy is likely to improve future travel conditions, but a combination of multimodal strategies offers significant improvements over congestion levels predicted for 2025 if no improvements are made.
Densification and Urban Compaction: Reinforcing the Drive for Sustainability
Authors: Cooper James , Donegan Karen , Ryley Tim , Smyth Austin , Granzow Ed
Published: April 2007

The consumer response to sustainable development initiatives provided the focus for a series of research projects undertaken at the Transport Research Institute at Napier University. Evidence of the relationship between residential density and travel behavior is presented. Results are presented from a large household survey undertaken in four settlement classes within one key commuter corridor of the Belfast City (Northern Ireland, United Kingdom) region to determine their comparative sustainability in terms of travel behavior. It can be concluded that wide-scale land use policies can achieve significant reductions in overall private vehicle travel in urban areas. Densification is best suited to established urban areas and for influencing modal shift primarily to walking rather than public transit. The work also suggests that a more focused approach to planning decisions reflecting housing market segment preferences could yield a win-win situation for house owners and developers, albeit at the expense of some reduction in residential plot size. Local changes can bring global benefits. A great challenge falls to the urban designer to ensure that such trade-offs do not unduly undermine quality of life. Further thoughts are provided on the implications for policy makers in car-dominated cities in the United States.
Contrasting Time-Based and Distance-Based Measures for Quantifying Traffic Congestion Levels: Analysis of New Jersey Counties
Authors: d'Abadie Robert R. J. , Ehrlich Theodore F.
Published: April 2007

Various approaches for quantifying congestion and how these different measures affect the perception of the problem are discussed. In a study done for the state of New Jersey, thresholds of the volume-capacity ratio on any given roadway were adopted to identify where congestion was occurring. The severity of this congestion was then analyzed by using both distance-based and time-based measures to describe the magnitude of the problems. It was found that the distance-based measures such as vehicle kilometers of travel indicated a relatively small amount of congestion to be present statewide. Time-based measures such as vehicle hours of travel in congestion revealed more severe problems, with more than half of total peak period travel time in many counties being spent in congested conditions. The time-based measures of congestion provided a stronger basis for more generalized conclusions. These measures indicated that much of the delay due to congestion in New Jersey could be attributed to the most severely congested locations in the state. These same time-based measures also strongly suggested that arterial roadways contribute far more to the overall congestion problem than previously reported. Time-based congestion measures provide a different perception on congestion, one in keeping with the common perception of the problem. Time-based congestion measures also provide stronger guidance on identifying major issues, enabling policy makers to better address problems within the state and solutions that are most likely to have the greatest impact.
Measuring System Performance: Key to Establishing Operations as a Core Agency Mission
Authors: Meyer Michael D.
Published: April 2007

Monitoring transportation system performance, especially the operations of the system, has become an important task for transportation agencies. The importance of monitoring system performance as a strategy for enhancing the operations function of transportation agencies is examined. The reasons for system monitoring are described, with special focus on the importance of system information for customer satisfaction. Examples are provided of state department of transportation and metropolitan planning organization use of performance measures to guide decisions on operations-oriented strategies. It is concluded that by collecting data on system operations and reporting them to decision makers, the importance of system performance compared with other concerns could be increased significantly. Simply defining such measures will not ensure that the institutional willingness exists to emphasize system management and operations as solution strategies. However, the measures can provide important ammunition for those supporting these concepts, and because of public interest in improving traffic flow conditions, as indicated by surveys, they could act as catalysts for developing a supportive public constituency.
Modifications to Traditional External Trip Models
Authors: Giaimo Gregory T.
Published: April 2007

Traditionally, internal-external trips were modeled by using regression-based trip generation equations and gravity model trip distribution. Applying these models at the cordon in the traditional way produces a number of problems. A typical solution is the use of external traffic analysis zones and highway networks that are used to model the external traffic similarly to internal traffic. Presented are modifications to each component of the traditional cordon line external model that will remedy these problems for those areas that do not wish to expand their data collection burden to areas outside their planning boundaries. In this model, trip distribution is a traditional cordon applied gravity model modified by using a composite impedance based on the product of travel time and an exponential function of the angular impedance. Angular impedance is defined as the angle between the vector representing the general direction of travel at the cordon and the vector defined by the cordon crossing point and a given internal zone centroid. The trip generation model is modified by the use of accessibility modified independent variables in the regression formulation. This model uses either traditional socioeconomic variables or internally generated production and attractions as the root variable. These root variables are then multiplied by an accessibility term similar to the denominator of the gravity model formula where internal-external trip productions at the cordon are used as the size variables. Application of these modifications to a small metropolitan planning organization in Ohio resulted in dramatic improvements to the model.
Origin and Destination Estimation in New York City with Automated Fare System Data
Authors: Barry James J. , Newhouser Robert , Rahbee Adam , Sayeda Shermeen
Published: April 2007

New York City Transit’s automated fare collection system, known as MetroCard, is an entry-only system that records the serial number of the MetroCard and the time and location (subway turnstile or bus number) of each use. A methodology that estimates station-to-station origin and destination (O-D) trip tables by using this MetroCard information is described. The key is to determine the sequence of trips made throughout a day on each MetroCard. This is accomplished by sorting the MetroCard information by serial number and time and then extracting, for each MetroCard, the sequence of the trips and the station used at the origin of each trip. A set of straightforward algorithms is applied to each set of MetroCard trips to infer a destination station for each origin station. The algorithms are based on two primary assumptions. First, a high percentage of riders return to the destination station of their previous trip to begin their next trip. Second, a high percentage of riders end their last trip of the day at the station where they began their first trip of the day. These assumptions were tested by using travel diary information collected by the New York Metropolitan Transportation Council. This diary information confirmed that both assumptions are correct for a high percentage (90%) of subway users. The output was further validated by comparing inferred destination totals to station exit counts by time of day and by estimating peak load point passenger volumes by using a trip assignment model. The major applications of this project are to describe travel patterns for service planning and to create O-D trip tables as input to a trip assignment model. The trip assignment model is used to determine passenger volumes on trains at peak load points and other locations by using a subway network coded with existing or modified service. These passenger volumes are used for service planning and scheduling and to quantify travel patterns. This methodology eliminates the need for periodic systemwide O-D surveys that are costly and time-consuming. The new method requires no surveying and eliminates sources of response bias, such as low response rates for certain demographic groups. The MetroCard market share is currently 80% and increasing. MetroCard data are available continuously 365 days a year, which allows O-D data estimation to be repeated for multiple days to improve accuracy or to account for seasonality.