bluuebunny/crossref_metadata_2025 huggingface dataset:
Road Traffic Noise Prediction Using Object-Oriented and Geographic Information System Technologies
Authors: Black J.A. , Samuels S.E. , Vandebona U. , Masters E. , Trinder J.C. , Morrison B. , Tudge R.
Published: April 2007

It is now some 4 years since the New South Wales Roads and Traffic Authority (RTA) interim noise policy was released. The document sets out RTA policies on traffic noise along with guidelines relating to assessment and control. It is perhaps the most extensive document on the topic ever produced by an Australian road authority. The underlying philosophy of the policy is the importance of noise as an issue that must be addressed in all aspects of RTA road planning, design, construction, maintenance, and operation programs. Some recent advances in the traffic noise arena are considered. A spatial decision support system is then outlined for road planning that has been developed as part of an Australian Research Council industry collaborative research grant involving RTA and the University of New South Wales. This is built on object-oriented programming and geographic information system technologies and involves a library containing models in eight domains amounting to 33,000 lines of code. The noise estimation procedure included in this system is described together with how it has been adapted and implemented in an object-oriented way. Speculation is made on how the prototype may be integrated into the emerging corporate responsibilities of RTA in the area of communication and consultation.
Impact on Montana’s Highways of Adopting Canadian Interprovincial and Canamex Limits on Vehicle Size and Weight
Authors: Stephens Jerry , Scoles James , Patterson Steve , Schillings Paul
Published: April 2007

The impact on Montana’s highways of adopting Canadian Interprovincial, Canamex, or Canamex Short limits on vehicle size and weight was determined. Canadian Interprovincial size and weight limits were developed with due consideration to safety, economy, and damage to highways. Canamex and Canamex Short limits are hybrid size-and-weight systems that retain Montana axle weights coupled with Canadian gross weights. Infrastructure impacts from these new and heavier vehicles were determined by developing new traffic streams, determining the physical impact of these streams on bridges and pavements, and assigning a cost to these impacts. These analyses found that 16 to 20 percent of the bridges systemwide are deficient under Canadian loads (incremental deficiencies above and beyond bridges already deficient under HS20 loads). Incremental deficiencies under Canamex and Canamex Short limits are between 1 and 3 percent of all bridges. Pavement demands on the Interstate and primary systems increased by less than 5 percent under all scenarios. These impacts represent cost responsibilities of $0.01 to $0.13, $0.01 to $0.05, and $0.01 to $0.09 per km driven on Interstate routes by the new configurations for Canadian, Canamex, and Canamex Short limits, respectively. Corresponding costs on the primary system were 1.2 to 10 times higher than these values.
Implementation Elements for Conversion of General-Purpose Freeway Lane into High-Occupancy-Vehicle Lane
Authors: Best Matthew E.
Published: April 2007

Conversion of a general-purpose freeway into a high-occupancy-vehicle (HOV) lane is an alternative to infrastructure addition for HOV system implementation. Research indicates that lane conversion is feasible technically if sufficient HOV usage and minimal main lane congestion occur from the first day of operation. The elements required for inclusion in an implementation plan for lane conversion to HOV after technical feasibility has been determined are presented. HOV-lane marketing is meant to heighten public awareness of the purpose and operation of HOV facilities while encouraging their use. The general public, local decision makers, and the local media are important elements to include in a marketing campaign for successful HOV implementation. These elements also apply to the successful implementation of lane conversion to HOV. Four HOV lane-conversion projects are investigated: (a) Santa Monica Freeway, Los Angeles, California; (b) Dulles Toll Road, Northern Virginia; (c) Interstate 90, Seattle, Washington; and (d) Interstate 80, northern New Jersey. The Santa Monica and Dulles projects are considered failures, whereas the Interstate 80 and 90 projects are considered successful. From these case studies and the literature review, implementation elements were identified: (a) technical feasibility, (b) early public outreach, (c) strong institutional arrangements, (d) inclusion of law enforcement agencies, (e) open relationships with the media, and (f) project opening timing.
OAK-TREE: One-of-a-Kind Traffic Research and Education Experiment
Authors: Sun Carlos , Recker Wilfred , Ritchie Stephen , Gallagher Brian , Shen Eric , Thai John
Published: April 2007

The creation and progress of OAK-TREE (One-of-a-Kind Traffic Research and Education Experiment) are chronicled. OAK-TREE is a traffic educational laboratory experiment that was developed and conducted at the University of California at Irvine (UCI) during the spring quarter of 1996. This project involved a cooperative effort between the academic community and public-sector transportation operating agencies in developing a comprehensive field and laboratory educational experience for undergraduate students in transportation engineering. The agencies involved in this effort were the Department of Civil and Environmental Engineering at the University of California at Irvine, the Advanced Traffic Surveillance and Control Center of the city of Los Angeles, the Transportation Management Center of the city of Anaheim, and the Irvine Traffic Research and Control Center of the city of Irvine. These agencies were instrumental in creating an innovative laboratory experience for academic training in the use of state-of-the-practice resources and methods for traffic engineering. The results were the development of a state-of-the-art traffic-control educational laboratory at UCI and the genesis of a unique traffic-control course that fulfilled the requirements of both fundamental academic education and rigorous professional training.
Influence of the Metropolitan Atlanta Rapid Transit Authority on Population and Employment Location
Authors: Nelsonand Arthur C. , Sanchez Thomas W.
Published: April 2007

The rail system operated by the Metropolitan Atlanta Rapid Transit Authority (MARTA) began operating in 1979. As its 20th anniversary nears, how has it influenced land use patterns? Results are mixed. Throughout the Atlanta metropolitan area, the population continues to sprawl outward and MARTA’s facilities do not appear to attract large-scale residential development to them. On the other hand, employment also continues to decentralize, and MARTA’s rail facilities appear to have attracted employment-based development. As MARTA extends service into the affluent northern tier suburbs, its attractiveness to employment centers and perhaps higher-density residential development should improve. The downside is that MARTA is exhausting its reach because most of the region’s new development is outside its jurisdiction.
Transit Friendliness Factor: Approach to Quantifying Transit Access Environment in a Transportation Planning Model
Authors: (Jay) Evans John E. , Perincherry Vijay , Bruce Douglas G.
Published: April 2007

In traditional travel forecasting models, a limited set of attributes are used to describe transit utility. The transit access environment is one of the characteristics of the travel experience often ignored by the models in use today. A quantitative approach to incorporating the effects of the transit access environment into transportation planning models is presented. A measure called the transit friendliness factor, which is defined as a function of the characteristics of the area surrounding a transit stop, is proposed. These characteristics include the quality of the pedestrian facilities, the character of nearby streets, the presence of amenities at the stop, and the proximity to potential destinations. A method for evaluating both the existing and the future value of the transit friendliness factor is described. Application of the proposed approach is illustrated by its successful implementation in the mode choice model used in a study for the Triangle Transit Authority in Research Triangle Park, North Carolina. In conclusion, the lessons learned and suggested future applications are discussed.
Use of Geographic Information System for Analysis of Transit Pedestrian Access
Authors: Hsiao Shirley , Lu Jian , Sterling James , Weatherford Matthew
Published: April 2007

The development and application of transit accessibility measures by geographic information system technology are described. The approach allows transit planners to focus on access to transit routes and bus stops at the neighborhood level and draws attention to the significance of the walk access mode to transit. Then land use, population, and employment characteristics are incorporated into the evaluation of transit service. A case study example of a “what-if” scenario for evaluation of transit service alternatives is discussed. Conclusions are offered about the use and further development of the approach for transit planners.
Research on Customer Requirements for Transit Service Design and Delivery
Authors: Glascock Jane
Published: April 2007

In the past, transit had a monopoly over service to large segments of society: one-car families or those who could not afford to drive. Now transit competes with the automobile for most consumers’ travel. To increase trip making and attract new customers in a competitive market, transit agencies must refocus from an internally driven orientation aligned with providing public service to an externally driven orientation aligned with the mission of delivering products and service that meet consumer expectations and requirements. Descriptive results of research to identify customer requirements for design and delivery of high-quality transit service are reported. Nearly 500 customers and potential customers of King County Metro Transit in Seattle, Washington, completed questionnaires designed to identify important elements and their performance requirements for each. The questionnaire was developed with intensive customer input to ensure that wording reflected customer and not staff perceptions. Requirements for service design included the following: 15-min headways for work and personal travel; no transferring to work; and total travel time to work no more than 50 percent longer than by car. Customer requirements for service delivery among elements that customers considered important included the following: the bus never leaves the stop early; seats are clean and dry; arrival time to work is no more than 5 min late; and windows are in good repair. Nonriders who were potential customers rated service delivery elements of transferring comparablity with automobile travel time as more important than did riders. Riders were more likely than nonriders to require 15-min headways for work travel.
Have We Lost the Message Before Gaining the Knowledge?
Authors: Rogers Lee H.
Published: April 2007

Professional documentation of transportation technology and project development from the past 12 decades is progressively being lost to the engineering and economic community. For more than three decades tons of books, reports, plans, and documents on myriad aspects of transportation have been discarded by local and national government agencies, university libraries, and private firms. Seldom have these groups sought alternative locations for their accumulated collections. The issues at the time of discard are not often related to proprietary aspects of the documents but rather appear to be based on the human reasoning that if the documents have no merit for the agency or firm in possession of them, then they have no interest for others. The issue is brought before professionals so that discussion and options may be explored. Given the electronic options in document retention and retrieval, the professional community has new opportunities to preserve and utilize the valuable insights of paper-based documents without incurring the expense of extensive floor space.
Effects of Font and Capitalization on Legibility of Guide Signs
Authors: Garvey Philip M. , Pietrucha Martin T. , Meeker Donald
Published: April 2007

The research objective was to improve highway guide sign legibility by replacing the 40-year-old guide sign font with a new font called Clearview. It was believed that the current guide sign font’s thick stroke design, made with high-brightness materials and displayed to older vehicle operators, exhibited a phenomenon known as irradiation or halation. Irradiation becomes a problem if a stroke is so bright that it visually bleeds into the character’s open spaces, creating a blobbing effect that reduces legibility. The Clearview font’s wider open spaces allow irradiation without decreasing the distance at which the alphabet is legible. Results are presented of two daytime and two nighttime controlled field experiments that exposed 48 older drivers to high-brightness guide signs displaying either the current or the Clearview font. The Clearview font allowed nighttime recognition distances 16 percent greater than those allowed by the Standard Highway Series E(M) font, without increasing overall sign dimensions.
Model Guidelines for Visibility of On-Premise Advertisement Signs
Authors: Thompson Kuhn Beverly , Garvey Philip M. , Pietrucha Martin T.
Published: April 2007

On-premise advertising signs play an important role in directing drivers. Well-placed and well-designed on-premise advertising signs can guide vehicle operators toward their destinations with minimal demand for attention. Poor placement of signs can sap a driver’s cognitive and perceptual resources, resulting in erratic maneuvers such as inappropriate slowing and lane changing. Increasingly, however, the visibility of on-premise advertising signs is being determined not by human factors researchers, visibility experts, or traffic engineers but by local planning and zoning officials, who lack specialized training in relevant fields. Regulations affecting on-premise sign visibility characteristics, such as means of illumination, lateral offset, and sign size, have been established mainly on the basis of arguments for improved aesthetic appeal and of vague, often unsubstantiated safety claims. There is a clear need to determine, from scientific and ergonomic perspectives, the effects these regulations have on sign visibility and traffic safety. An organized synthesis of existing literature on sign visibility based on 60 years of research and consisting of more than 150 journal articles and technical reports is presented. The synthesis may be used by sign designers to optimize the visual effectiveness of their signs. It also can provide a scientific basis for the development of new on-premise sign regulations or changes to existing regulations. A model set of guidelines for designing and locating on-premise advertisement signs for conspicuity and legibility is provided.
Experience of Metropolitan Planning Organizations with Intermodal Surface Transportation Efficiency Act Financial Planning Requirements: Interviews and Analysis
Authors: Bishop Elbert R. , Wornum Christopher , Weiss Martin
Published: April 2007

The Intermodal Surface Transportation Efficiency Act of 1991 (ISTEA) requires metropolitan planning organizations (MPOs) to develop financially constrained metropolitan transportation plans and programs. FHWA officials believed that independent studies were needed if problems with the requirement were to be understood. A summary of findings of those studies along with an analysis by an FHWA official are presented. Financial planning requirements were found to be generally well received. Fiscal constraint requirements can be traumatic, but there is agreement that realistic programs are worth having. Reconciling costs with revenues was found to present MPOs with the most severe difficulties. Allowing contingency projects and revenue sources and smoothing the transportation improvement program amendment process can retain fiscal realism while diminishing the trauma of cost-revenue reconciliation. Underestimation of capital and operating and maintenance costs to balance a plan were found to be probable. Dissemination of “best practice” examples by FHWA and FTA and MPO self-policing appear to be the most likely corrective actions. It was found that few MPOs considered technologies to reduce operations and maintenance costs. Placement of such technologies will be slow. MPO personnel were found to have encountered more constraints than expected in using the modal flexibility provisions of ISTEA. More MPO regional coalition building will be needed to meet flexibility expectations. Despite availability, it was found that FHWA and FTA information, reports, and software concerning nonfederal sources of revenue were not obtained by officials desiring them. MPOs are encouraged to rely more on expert assistance to implement local funding sources.
Statewide Transportation Policy Planning: Pennsylvania’s Collaborative Approach
Authors: Smithmyer Kent E. , Dikes Shawn P.
Published: April 2007

The Pennsylvania Department of Transportation (PennDOT) determined that a collaborative approach would be most effective for compliance with Intermodal Surface Transportation Efficiency Act of 1991 (ISTEA) requirements for the development and implementation of its Statewide Transportation Policy Plan. The process for developing and adopting the plan, along with its companion document, the Performance Report, included cooperative efforts among PennDOT and its transportation partners. Both documents were developed within the contexts of current and future planning initiatives and tailored to fit PennDOT’s overall business strategy, mission statement, and vision for the 21st century. Plan development activities included data collection, cooperative and coordinated planning efforts with metropolitan planning organizations and local development districts, consideration of ISTEA’s 23 planning factors, coordination with private and public transportation interests, and extensive outreach and consensus-building programs. The performance report was conceived as part of the policy plan to measure the status of the transportation system and answer the question, “What difference did it make to have the policy plan?” The report adopted an economic approach to performance, measuring supply, usage, and condition. The report was used to articulate a “maintenance first” philosophy, highlighting PennDOT’s continuing struggle to fund transportation programs and dispelling public myths and misconceptions about transportation in the commonwealth. Lessons learned during development, data collection, and outreach activities are applicable to other states still developing or refining their plans. Discussions of these activities, future endeavors, and the path forward are critical, especially in light of ISTEA reauthorization and the trend toward a more fiscally and, perhaps, politically constrained national transportation context.
Technical Report of Southern California Association of Governments’ Transportation Performance Indicators
Authors: Ikhrata Hasan , Michell Patrick
Published: April 2007

The overall goal of the staff of the Southern California Association of Governments (SCAG) is to develop specific, quantifiable, and easily understandable performance indicators for the region’s transportation system that better inform elected officials and policy boards of the broad array of choices for investing public and private funds. SCAG’s performance indicators are intended to capture the important relationships between transportation and a diversity of public policy concerns. The seven performance indicators used in the preparation of the 1997 Regional Transportation Plan (RTP) are mobility, accessibility, environment, cost-effectiveness, reliability, safety, and customer satisfaction. SCAG applies these performance indicators to each of its 13 subregions and to the region as a whole. The federal Intermodal Surface Transportation Efficiency Act of 1991 and Clean Air Act Amendments of 1990, and SCAG’s 1994 Regional Mobility Element, set the stage for the abandonment of the old and popular level of service measure. SCAG’s performance indicators approach the concept of performance from the perspective of the users of the transportation system, in contrast to traditional approaches that focused more on facilities and vehicles. SCAG is currently at approximately the midpoint in the development of the 1997 RTP and therefore has considerable practice in working with the performance indicators. This experience confirms the value of performance indicators as a planning tool.
Developing Public Awareness and Acceptance of Metrication: Preliminary Analysis
Authors: Buchanan Raymond W. , Chang Kyu Y.
Published: April 2007

The three major arguments made by opponents of metrication—cost, confusion, and cultural perception—are addressed. Research into these factors has suggested that encouraging the use of metrication is not an impossible task if strategic planning for a comprehensive communication campaign is conducted.
Waterborne Passenger Transportation Planning in Rhode Island
Authors: Braum Philip H. , Reardon Martha A. , Keefe Marjorie A.
Published: April 2007

The state of Rhode Island had no plan for waterborne passenger transportation, even though the state sits astride Narragansett Bay and has several existing ferry operations. The Rhode Island Department of Transportation (RIDOT) recognized the need to create such a plan to clarify the desired role of waterborne transportation in the state’s transportation system and the agency’s responsibility for its development. RIDOT undertook the development of a waterborne passenger transportation plan to guide decisions about capital investments, to provide a basis for seeking federal funding, and to assist ferry operators in their decisions about establishing or expanding services. The plan addresses a broad range of issues and includes a set of policies and actions for the state’s waterborne passenger transportation system.
Probabilistic Method of Asphalt Binder Selection Based on Pavement Temperature
Authors: Lukanen Erland O. , Han Chunhua , Skok Eugene L.
Published: April 2007

The Strategic Highway Research Program, conducted in the United States and Canada from 1987 to 1992, included a significant asphaltic concrete study. The study included a new grading method for asphalt binders, performance grading, resulting in what is termed PG asphalt. The grade selection process is based on air temperature distribution. Since 1994, the Long-Term Pavement Performance program has established a seasonal monitoring program that consists of a number of sites with air and pavement temperature sensors and a data logger that records the air and pavement temperatures hourly. These data are now available for prediction of the extreme temperatures that are needed for the selection of the appropriate PG asphalt binder. On the basis of the review of the recent pavement temperature studies and statistical analysis of the pavement temperature data available, an empirical prediction model has been developed from the original data set and validated from the expanded data set. The model is compared with existing prediction relationships including the heat flow model. Pavement prediction data and climatic data on high and low temperature from weather stations are used to calculate the probability that a specific asphalt temperature will be exceeded. Variations both in prediction and in annual maximum or minimum air temperature are assumed to be independent and considered in the calculation. The reliability contours for a given PG grade are presented as a convenient tool to the asphalt binder selection.
Stabilization Characteristics of Clays Using Class C Fly Ash
Authors: Misra Anil
Published: April 2007

Coal-burning utilities using subbituminous coal from Wyoming typically produce fly ash, which, because of its high calcium oxide content, may be classified as Class C fly ash. These ashes are characterized by their self-cementing property and therefore can be used for soil improvement. Stabilization characteristics of clay soils blended with Class C fly ash were evaluated. Because fly ash is a by-product, uniformity of its physical and chemical properties is significant for quality control. The statistical characteristics of fly ash physical and chemical properties are obtained and compared with the data in literature. Fly ash is blended with several different clay soils of varying plasticity to study moisture-density relationships and strength behavior of stabilized soils. It is observed that the fly ash used in these experiments has a rapid hydration characteristic. Consequently, higher densities and strengths are achieved when the compaction is performed with little or no delay after the addition of moisture to clay-fly ash blends. Conversely, delayed compaction produces low densities and strength. In addition, it is observed that the stabilization characteristics are closely related to the soil mineral type and plasticity. Results also are presented for strength gain behavior with curing period for the various soil-fly ash blends.
Driver Eye and Vehicle Heights for Use in Geometric Design
Authors: Fitzpatrick Kay , Lienau Torsten , Fambro Daniel B.
Published: April 2007

Driver eye, headlight, taillight, and vehicle heights are important elements for determining passing and intersection sight distances and horizontal and vertical curve lengths to provide required stopping sight distance. Driver eye and object heights have varied significantly since their inception in the 1920s, when their values were suggested as 1676 mm. The objective of this study was to determine appropriate driver eye, headlight, taillight, and vehicle heights for use in developing geometric design criteria. The results of this research were used to recommend a driver eye height of 1080 mm for design purposes. This value represents 90 percent of the passenger car driver eye height values and an even higher percentage of the total vehicle fleet, because passenger cars have the lowest driver eye height values and represent fewer than two-thirds of the total vehicle fleet. Headlight and taillight heights of 600 mm are recommended for design. These values represent over 90 and 95 percent of the passenger cars observed in this study, respectively. The vehicle height recommendation for sight distance was 1315 mm, which represents the 10th percentile passenger car height values measured in the research.
Highway Alignment: Three-Dimensional Problem and Three-Dimensional Solution
Authors: Hassan Yasser , Easa Said M. , Abd El Halim A. O.
Published: April 2007

Highway geometric design has usually been considered in separate two-dimensional (2-D) projections of horizontal and vertical alignments. Such a practice was followed mainly because three-dimensional (3-D) analysis of combined highway alignments was expected to be difficult. As a result, the effect of ignoring the 3-D nature of the highway alignment could not be quantified. With the long-term objective of developing 3-D design practice, a framework for 3-D highway geometric design was developed and 3-D sight distance was extensively studied as the first design basis. The status of sight distance in current design policies and previous research is summarized, and mainly 2-D analysis was considered. The five main tasks performed to cover the 3-D highway sight distance are presented. ( a) As a preliminary step, the 2-D sight distance on complex separate horizontal and vertical alignments was modeled, and the finite element method was used for the first time in the highway geometric design. ( b) The 2-D models were then expanded to cover the daytime and nighttime sight distances on 3-D combined alignments. ( c) The analytical models were coded into computer software that can determine the available sight distance on actual highway segments. ( d) The models were applied in 3-D design of combined horizontal and vertical curves in cut-and-fill sections, and preliminary design aids were derived. ( e) Finally, a new concept of red zones was suggested to mark the locations on alignments designed according to current practices where the available sight distance will drop below that required. A comprehensive work on 3-D sight distance analysis has been compiled that should be of great importance for highway researchers and professionals.
Instrumentation and Calibration of Geotextiles Used in Centrifuge Modeling of Slopes
Authors: Mahmud Mahadzer B. , Zimmie Thomas F.
Published: April 2007

Research on the application of geotextile strips used as reinforcement in marginally stable soft soil slopes was performed with a geotechnical centrifuge. A variety of instrumentation was used in the model studies. When centrifuge models are used, the elements being modeled must be scaled down by the level of centrifuge acceleration—that is, the g level used in the modeling process. This results in the use of very small geotextile reinforcing strips, which are difficult to instrument. In this study, small strips of nonwoven geotextile were driven into the model slope while the centrifuge was in flight. These strips were instrumented with miniature foil-type strain gauges. The following items are discussed in detail: various stages of installation of the strain gauges on nonwoven geotextiles, selection of suitable bonding techniques, use of thin coatings for gauge protection, and selection of suitable bridge excitation voltages for the gauges. The devices used in the calibration process, and the calibration results, are presented.
Calculation of Settlements of Shallow Foundations on Sand and Silt Based on In Situ Test Results
Authors: Larsson Rolf L.
Published: April 2007

Calculations of settlements of foundations on sand and silt are often made with methods that do not take into account the curved load-settlement relations. With reasonable accuracy, these methods can be used to calculate settlements only for the “normal” ground pressures for which they have been elaborated. For lower ground pressures the settlements become overestimated and for higher pressures they become increasingly underestimated. However, new design rules often contain varying demands for acceptable settlements depending on the type of structure. The failure criteria for bearing capacity are also more often defined in terms of large relative settlements than of actual failure. This leads to higher demands for accurate predictions of settlements over a wide range of possible ground pressures. New methods of predicting the load-settlement curves for shallow foundations have been proposed and two of these methods have been compared and calibrated against the results of a series of plate load tests in Sweden. Both methods appear to greatly improve the possibilities of accurate predictions of settlements and failure loads based on settlement criteria.
Evaluation of Strain Variation Within a Triaxial Specimen Due to End Effects
Authors: Pezo Rafael , Picornell Miguel , Nazarian Soheil
Published: April 2007

A new triaxial test setup is described that has been developed to test large specimens (150 mm in diameter and 300 mm long). The system was designed to use eight proximitors: two placed on opposite ends of a diameter at midheight of the specimen to measure lateral deformation and six placed in pairs along the specimen and distributed at 120 degrees around the specimen to measure axial deformations. To calibrate this setup and to cover the typical range for highway base materials, nine elastomer specimens were manufactured with three different stiffnesses. A quasi-static test program was implemented with these specimens to evaluate the capabilities and shortcomings of the system, the repeatability and accuracy of the test results, and the optimization of the gauge length to be used for measuring axial strains in the production test system. An axisymmetric computer model was assembled to predict axial and lateral deformations at the measuring points used in the experimental program. The experimental and numerical results are in fairly good agreement except in the vicinity of the loading end platens. The numerical results indicate overprediction of the moduli by about 15 percent when the gauge length used is the whole length of the specimen instead of the central one-fifth. The experimental data show somewhat higher discrepancies (about 20 percent) for the same range of gauge lengths.
Assessment of On-Sample Instrumentation for Repeated Load Triaxial Tests
Authors: Dawson Andrew R. , Gillett Simon D.
Published: April 2007

Five laboratories have been involved in a series of comparative studies of the repeated load triaxial testing of soils and unbound granular materials as found in the lower layers of pavement construction. These comparisons with soil, granular materials, and an artificial specimen are outlined. The performance of the varied types of instruments that measure both axial and radial deformations is assessed, with particular attention to the fixing arrangements, instrument limitations, and weight. On the basis of the information presented, recommendations are given about the most appropriate types of instrument. No universal type is recommended, and it is clear that some variation in performance is an inevitable consequence of the measurement process.
Neural Network Modeling of Anisotropic Aggregate Behavior from Repeated Load Triaxial Tests
Authors: Tutumluer Erol , Seyhan Umit
Published: April 2007

Determining horizontal specimen response in a repeated load triaxial test is essential to properly characterize the directional dependency of unbound aggregate resilient behavior under anisotropic loading conditions. Recent research has applied artificial neural networks (ANNs) for predicting, in the absence of lateral deformation data, the anisotropic stiffness properties of granular materials from standard AASHTO tests. Feed-forward backpropagation-type neural networks were successfully trained with two triaxial stresses (confining pressure and applied deviator stress), measured vertical deformation, and two aggregate properties (compacted dry density and crushed particle percentage) used as input variables. The output variables were the horizontal and shear moduli for which the actual (target) values were derived and computed from test results. The ANN models predicted the two moduli, with mean errors of less than 3 percent compared with those computed by using experimental stresses and strains. Both the applied stress state and the aggregate properties were found to affect the generalization and thus the prediction ability of the ANN models.
Precision and Accuracy of the Ignition Method for Determining Asphalt Content: Florida Round-Robin Study
Authors: Choubane Bouzid , Musselman James A. , Page Gale C.
Published: April 2007

To implement the ignition method for both quality control and acceptance purposes in Florida, the State Materials Office of the Florida Department of Transportation (FDOT) carried out a round-robin study to determine the precision and accuracy of this procedure for local conditions. Twelve materials laboratories, including both public and private sectors throughout Florida, participated in the investigation. Each of the 12 participant laboratories received a total of 36 hot-mix asphalt (HMA) mixture samples for asphalt content determination and gradation analysis. Samples were prepared in accordance with FDOT specifications with six different types of aggregate and one type of asphalt cement. Six laboratories used one ignition tester brand and the remainder used a tester from a different manufacturer. The testers, similar in nature, both include an internally mounted load cell and an automated system for data collection and processing. The interlaboratory test data were collected and analyzed at the FDOT State Materials Office. The round-robin test program is described and the accuracy and precision of the ignition method on materials commonly used in HMA construction in the state of Florida are discussed.
Georgia Department of Transportation’s Experience with Microsurfacing
Authors: Watson Donald , Jared David
Published: April 2007

Microsurface mix, or microsurfacing, can be used for sealing and providing a friction surface for cracked and deteriorated surface mixes. This mix, essentially consisting of 9.5-mm (0.37-in.) screenings bonded by a polymer-modified asphalt emulsion, is economical and can be placed very swiftly. Microsurfacing is also aesthetically pleasing because of its resemblance to hot-mix asphalt. In 1990–1991, the Georgia Department of Transportation (GDOT) successfully used microsurfacing in a test section on I-75 in Henry County, which had high traffic volumes and a heavy truck concentration. Two varieties of the mix were used, and both showed little deterioration after 2 years. In 1996, GDOT opted to use microsurfacing for a 9.2-km (5.7-mi) section of I-285 in Atlanta between Conley Road and Old National Highway. This 92 lane-km (57-lane-mi) project was initiated to address the raveling and cracking in the section and improve its appearance before the 1996 summer Olympics. The I-285 project began in late May 1996 and was completed in 1 month. The microsurfacing used on I-285 has performed quite well since the project was completed. No additional problems with raveling or load cracking have been encountered. The mix has provided excellent smoothness and good friction, with a minimal increase in pavement noise levels. Microsurfacing may be suitable for use on cracked pavements in lieu of more conventional rehabilitation methods such as crack sealing, leveling, and double surface treatments.
Transportation Economic and Land Use System
Authors: Pignataro Louis J. , Wen Joseph , Burchell Robert , Lahr Michael L. , Strauss-Wieder Ann
Published: April 2007

The purpose of the Transportation Economic and Land Use System (TELUS) is to convert the transportation improvement program (TIP) into a management tool. Accordingly, the system provides detailed and easily accessible information on transportation projects in the region, as well as their interrelationships and impacts. By doing so, TELUS enables public-sector agencies to meet organizational, Intermodal Surface Transportation Efficiency Act, state, and other mandates more effectively. The objectives are accomplished by providing the computer-based capability to analyze, sort, combine, and track transportation projects in or under consideration for a TIP; assessing the interrelationships among significant transportation projects; estimating the regional economic and land use effects of transportation projects; and presenting project information in an easily understood format, including geographic information system formats.
Unintended Consequences of Policy Decisions: Whatever Happened with the Intermodal Surface Transportation Efficiency Act Management Systems?
Authors: Lindquist Eric
Published: April 2007

The concept of “unintended consequences of policy decisions” is introduced as one potential outcome of the implementation of transportation policy. An unintended consequence is one that diverges from an authorized or directed policy action. This concept is illustrated by an assessment of the short-lived transportation management systems mandate in the Intermodal Surface Transportation Efficiency Act of 1991. Policy implementation theory suggests four propositions as an assessment framework: intergovernmental linkages, communication between linkages, organizational capacity of the implementing agency, and interpretation of the policy message. Problems in all four elements contributed to unintended consequences of the management system mandate and its eventual reversal in 1995. Implementing transportation policies and mandates has become increasingly complex; a more informed understanding of the policy-making process, and the conditions under which unintended consequences can occur during the implementation stage, will influence better policy design and implementation efforts.
Driven to Shop?: Role of Transportation in Future Home Shopping
Authors: Gould Jane
Published: April 2007

This study explores some of the transportation implications emerging from electronic home shopping and on-line commerce. It suggests that travel activities and travel patterns are likely to change as electronic commerce develops and as existing stores and commercial activities adjust to future competition from on-line commerce. The study illustrates some of the complex and unanticipated interactions that are likely to take place between the growth of new communication systems and transportation. In today’s retail markets, most goods are shipped to stores and people physically travel to stores to purchase goods. This tradition is likely to change with the growth of electronic home shopping, since many goods will be purchased on-line and consumers will not need to travel to shop. However, many items will require delivery to the home, and this may spur the expansion of home-delivery services. Other goods purchased on-line will require no physical distribution, and a new class of products, such as music CDs and software, is already being “shipped” electronically over broadband networks. Another impact of future electronic home shopping is the likely growth of entirely new types of retail venues, since it becomes easier to establish markets that bring together buyers and sellers who do not travel to meet, and without the movement of physical goods either. The shipping of goods takes place only after the transaction. All of these new market forms, which bring together electronically buyers, sellers, and goods, raise new issues for the study of transportation and communication interactions.
Reaching Jobs in the Suburbs: Tri-Rail in South Florida
Authors: Hadj-Chikh Gibran J. , Thompson Gregory L.
Published: April 2007

Continued expansion of development into suburban areas has led to increased suburb-to-suburb travel, which has contributed to the relative decline in ridership of commuter rail systems from the suburbs to the central business district (CBD). If commuter rail is to remain a viable element of the urban transportation network, it must serve new markets. The potential of commuter rail to serve suburb-to-suburb markets is examined. The size of the potential market for suburb-to-suburb commuter rail travel is estimated and compared with that of the suburb-to-CBD market. The mean market penetration is compared for suburb-to-suburb and suburb-to-CBD markets to determine whether there is a statistically significant difference between the two markets. The relationship between station-to-station distance and market penetration is tested for both the suburb-to-suburb and suburb-to-CBD markets. The results of this study indicate that the total potential ridership market for suburb-to-suburb home-based work trips is comparable with that for suburb-to-CBD homebased work trips. However, market penetration is greater for suburb-to-CBD trips than for suburb-to-suburb trips. Market penetration is found to increase with distance; however, initial results indicate that other factors affect market penetration more than distance.
Land Use and Transit Integration and Transit Use Incentives
Authors: Khasnabis Snehamay
Published: April 2007

Planners have often looked on transportation policies as a means of controlling broad patterns of land use. It has been argued that past transportation policies have contributed to decentralization of urban activities resulting in congestion, traffic hazards, and environmental pollution. Others contend that urban land uses reflect location decisions by individual households and employers and that transportation is just one of the many factors that affect such decisions. Thus, public policies in transportation have very little opportunity to alter future land use. The exact effect of transit on the distribution of urban activities, the resulting urban structure, the level of congestion, and air quality is not fully understood. An attempt is made in this paper to document successful cases of transit and land use integration as well as the techniques used by different agencies to bring about such integration. Various studies under the Transit Cooperative Research Program on different aspects of transit and land use policies serve as the basic sources of information for this paper. Eight case studies are examined that encompass a variety of transit modes in urban North America. It is concluded that the accessibility advantages provided by transit may play a crucial role in the concentration of development and in creating economic opportunities. However, transit by itself is not sufficient to guarantee successful transit-focused development. Other major factors are supportive regional and local policies and private investment in concert with the transit program. Further, successful transit and land use integration does not necessarily imply the presence of a high-speed rail system. In a strong market, when support policies are in place, light rail and busways can also be used to channel urban growth.
Outlay Rates and the Politics of Capital versus Operating Subsidies in Federal Transit Finance
Authors: Li Jianling , Taylor Brian D.
Published: April 2007

“Outlay rate” is a measure of the lapsed time between the obligation of federal funds for some purpose and the actual drawdown, or expenditure, of those funds. Outlay rates are an important, though often unspoken, reason for the gradual withdrawal of federal operating support of public transit. Rationales for reducing and/or eliminating federal support of transit operations are examined, overall capital and operating outlay rates for a sample of transit operators in California are measured, and possible causes and effects of federal grant outlay rates are discussed. On average, transit operators do, in fact, expend operating grants more quickly than capital grants. However, the overall size of the grant is actually a better predictor of slow outlays than grant purpose. Although the revenues generated by unexpended transit grants represent real revenues to the treasury, the goal of the federal transit program clearly is not simply to maximize such revenues. Evidence from other studies suggests that strict separation of capital and operating grants contributes to less efficient, overcapitalized transit systems, and an emphasis on capital grants may cost the federal treasury in the form of reduced tax revenues resulting from the lower economic multiplier of capital versus operating grants. Thus, it is unlikely that society benefits from a “float-driven” federal transit subsidy policy. Because federal transit grants seek to generate an array of social and economic benefits far broader than interest earned from the float from unexpended grants, the costs of the current capital-oriented or possible capital-only programs should be more systematically considered.