bluuebunny/crossref_metadata_2025 huggingface dataset:
Developing Transportation-Related Environmental Policy for the United States-Mexico Border Region
Authors: Cockerill Kristan , Espinosa Judith M.
Published: April 2007

Stressing the strong ties between transportation and environmental concerns, researchers at the Alliance for Transportation Research Institute (ATRI) developed a unique repository for Border Region Information on Transportation and the Environment (BRITE). BRITE’s purpose is to provide relevant environmental information to transportation agencies and planners working in the United States–Mexico border region. BRITE is being created in phases, but it is not a static entity and will never be “complete.” Each BRITE segment is generated from an extensive literature review. This paper provides an example of how the information from the literature review can be applied to developing better monitoring programs and better environmental policy relevant to transportation in the border region. Using the information gathered in the first BRITE segment, the authors identified alternative monitoring methods to assist agencies in ensuring compliance. The authors conclude that successful monitoring involves gathering data on environmental conditions via technical means as well as remaining abreast of policy and regulatory issues by establishing strong communication links with other agencies. Building on the importance of multifaceted monitoring, ATRI researchers created a framework to allow agencies to develop an environmental policy responsive to needs in the U.S.-Mexico border region. The framework is structured along a continuum to allow agencies to develop a personalized policy to reflect their needs and interests. The authors assess the overall project and conclude that meeting transportation needs in concert with addressing environmental concerns requires a clearly articulated policy that emphasizes communication and collaboration.
Prediction of Bearing Capacity of Friction Piles in Soft Louisiana Soils by Cone Penetration Test
Authors: Abu-Farsakh Murad Y. , Titi Hani H. , Tumay Mehmet T.
Published: April 2007

A comparison of four different methods for predicting the axial compression capacity of single piles using cone penetration test (CPT) results is presented. Nineteen pile load tests and parallel CPT soundings conducted close to the piles were identified and documented from the Louisiana Department of Transportation and Development archives. Piles with different sizes and lengths were investigated. The four prediction methods selected were the Schmertmann method, the de Ruiter and Beringen method, the French Central Bridge and Pavement Laboratory (LCPC) method, and the Tumay and Fakhroo method. An evaluation scheme was performed using these methods to assess their capability to reliably predict the axial compression capacity of piles installed in soft Louisiana soils. The predicted pile capacities obtained by the different methods were compared with the measured pile capacities obtained from pile load tests. Analysis of the results showed that the Schmertmann, de Ruiter and Beringen, and Tumay and Fakhroo methods predicted the ultimate compression capacities of piles installed in soft Louisiana soils with a reasonable accuracy. The LCPC method underpredicted the measured capacities of these piles.
Metro-North’s Cortlandt Station: Regional Intermodal Success Story
Authors: Bennett Christopher K.
Published: April 2007

The Metro-North Commuter Railroad was created in 1983 to operate, maintain, and manage the commuter railroads that were abandoned by Conrail in response to federal legislation. Working after January 1, 1983, Metro-North has improved the structures and facilities, stations, and track and electrical systems that had long been neglected by predecessor railroads. Over the course of the past 15 years, expenditures have averaged approximately $100 million yearly. This funding was provided through a series of capital programs initiated by the Metropolitan Transportation Agency, the umbrella agency that controls the New York metropolitan region’s transit properties. Funding for these projects is derived from various sources, including taxes, bond sales, state grants, and Federal Transit Administration grants. Projects often involve interaction with local communities, state and federal funding agencies, and special interest groups. The Cortlandt Station, with a total project cost of almost $11 million, was one example of the success that can be achieved in the public transportation arena when a local municipality is convinced it is part of the planning and design process. Although the overall planning and implementation took nearly 9 years to complete, the Cortlandt Station has turned out to be one of the railroad’s major successes. It is also an excellent example of the coordination that is required to execute a major improvement project when several state and federal agencies, four design and engineering consultants, and three contractors are added to the mix.
Are Incident Management Programs Effective? Findings from Washington State
Authors: Carson Jodi L. , Mannering Fred L. , Legg Bill , Nee Jennifer , Nam Doohee
Published: April 2007

The development of an incident response team (IRT) program has been touted to improve incident response and clearance times, as well as to improve interdisciplinary cooperation. To determine the effectiveness of its IRT program, the Washington State Department of Transportation (WSDOT) commissioned a comprehensive study that considered both quantified and perceived benefits. The average duration of incidents to which the IRTs responded was reduced by 20.6 min from 1994 to 1995. The ability to statistically attribute this reduction in incident duration to the IRT was limited because only 2 years of data were available (i.e., reduction may be attributable to temporal variations in incident characteristics). Nonetheless, the implications of this reduction can be quantified. This reduction results in a monetary savings of $20,600 to $61,800 per incident and an annual savings of $3.09 million to $9.27 million in King County. Comparing these monetary benefits to the IRT program, costs in the Northwest Region result in a benefit-to-cost ratio of 4.3:1 to 12.9:1. Given these values, even minor reductions in incident duration attributable to IRTs can justify the program. Public support for WSDOT’s incident response team program was high, with 62 percent of the respondents thinking it is a good idea. IRT program support from other response personnel was also high. WSDOT’s IRT was viewed as an important service for improving scene accessibility and improving the safety of both the motoring public and the incident responders. Despite the positive feedback, inconsistency in operation among individual IRT members makes it difficult to draw conclusions as to the effectiveness of different operating styles, for other response personnel to work effectively with IRT members, and to build a positive consensus among the motoring public for continued program support.
Evaluation of Diamond Interchange Signal Controller Settings by Using Hardware-in-the-Loop Simulation
Authors: Koonce Peter J. V. , Urbanik Thomas , Bullock Darcy
Published: April 2007

Research sponsored by the Texas A&M University ITS Research Center of Excellence was used to analyze the application of hardware-in-the-loop simulation at a diamond interchange. The study shows that hardware-in-the-loop simulation can improve the accuracy of traffic operations analysis by removing the inherent differences between emulated controllers and the actual hardware. In this study, a controller enhancement called conditional service was considered for implementation at an actuated diamond interchange. An evaluation of the traffic operations at the diamond interchange was completed using PASSER III-98, CORSIM, and hardware-in-the-loop simulation. The results of these analyses were compared to field observations that were used as the basis for evaluating the accuracy of each of these methods. An assessment of each method was discussed to identify issues and results using each method. One of the important supplementary benefits of hardware-in-the-loop simulation is that it allows engineers and technicians to test signal control strategies and hardware before deployment in the field. This capability provides a platform for innovation and the development of new control strategies. Hardware-in-the-loop simulation is also a valuable training tool.
Determining Capacity Benefits of Real-Time Signal Control at an Intersection
Authors: Skabardonis Alexander , Gallagher Brian R. , Patel Kartik P.
Published: April 2007

Traffic responsive control strategies are increasingly being implemented to improve intersection performance. Critical intersection control (CIC) is using real-time traffic data to better assign green times to conflicting movements. However, the benefits of CIC have not been assessed, and existing methodologies for estimating intersection performance do not account for CIC or other traffic responsive control strategies. The effectiveness of CIC was evaluated at seven signalized intersections in the city of Los Angeles. The findings indicate that CIC generally improves traffic operations. The ongoing evaluation of additional test sites will result in guidelines and adjustment factors in estimating intersection performance under CIC using the Highway Capacity Manual and other analysis techniques.
Evaluating a Roadside Assistance Program: Penn-Lincoln Parkway Service Patrol
Authors: Donnell Eric T. , Patten Michael L. , Mason John M.
Published: April 2007

The results of a preliminary evaluation of the Penn-Lincoln Parkway Service Patrol are summarized. The Pennsylvania Department of Transportation contracts with a local towing company to operate the Service Patrol on the Penn-Lincoln Parkway (PA Route 60, U. S. Route 22, and Interstates 279 and 376) in the Pittsburgh metropolitan area. The Service Patrol, consisting of specially equipped tow trucks driven by specially trained drivers, provides assistance to disabled vehicles along the parkway, thus reducing traffic delays and congestion. Service patrol hours of operation are during the morning and afternoon peak travel hours. The length of highway included in the evaluation is approximately 32 km (20 mi). The evaluation compared data from the period January–April 1997 with incident data collected by the Pennsylvania State Police during the corresponding period in 1996. The data were analyzed to determine the effect of the Service Patrol on incident response times, incident clearance times, and incident-related congestion factors (i.e., vehicle-hours of delay, fuel consumption, and vehicle emissions). This evaluation yielded the following results: ( a) the Service Patrol reduced incident response times by approximately 8.7 min; ( b) the Service Patrol cleared incidents approximately 8.3 min faster than before implementation; ( c) the Service Patrol reduced hours of delay by approximately 547,000 h per year; ( d) total monetary savings resulting from implementation of the Service Patrol are approximately $6.5 million per year; and ( e) the public response to the Service Patrol is overwhelmingly favorable.
Using Commodity Flow Survey Data to Develop a Truck Travel-Demand Model for Wisconsin
Authors: Huang Wen-Jing , Smith Robert L.
Published: April 2007

Four similar truck travel-demand (TTD) models were developed for Wisconsin using 1993 Commodity Flow Survey (CFS) origin–destination (O-D) data and a limited number of truck classification count data. First, statewide zonal-level trip tables were developed using the CFS database. Then gravity models for four trip types were calibrated to match the trip-length frequency distributions of the CFS O-D trip tables. Finally, zonal trip productions and attractions were adjusted using an iterative procedure to match assigned traffic volumes with truck classification count data for 40 selected links. The four alternative TTD models differed only in the method used to assign external trips to the external stations. All of the models provided reasonable levels of goodness-of-fit to the 40 selected calibration links, as well as 104 additional count locations across the state. The primary limitation of the four models was that they substantially underestimated the truck trips that crossed the state boundary. The CFS data focused on longer-distance transport of major commodities; therefore, the local truck trips that used the external stations were underrepresented in the model. Simple regression models for estimating trip productions and attractions were developed using zonal population and employment as the independent variables. These improved models were possible because the CFS data made available more detailed initial estimates of trip productions and attractions.
Accessibility Indices: Pilot Study and Potential Use in Strategic Planning
Authors: Schoon John G. , McDonald Michael , Lee Adrian
Published: April 2007

Accessibility indices (AIs) for public and private transport were estimated in a pilot study in northeast Hampshire, England. The AIs were based on a formulation relating travel time and cost between specified origins and destinations (O-Ds). Wider use of the role of the indices was examined, particularly for reducing car dependency as one element in improving sustainability within the North East Hampshire Transport Strategy. The indices, which can be presented in simplified graphical fashion to inform nontechnical audiences, are based on door-to-door travel times and costs, and the O-Ds represent trips between home and important destinations. Significantly, the only example in which travel-cost AIs for bus versus car travel were approximately equal was that in which a substantial car-parking charge was made. The AIs thus help to indicate the transport corridors where actions to improve equity in transport opportunities for users have the greatest priority and potential. These actions, such as improved bus priority and varying fare levels, parking charges, and other user charges, can be verified by prescriptive use of the AIs to illustrate the impacts. This approach provides a basis for using the AIs to quickly examine future transport scenarios and in associated decision making. It also helps in focusing on detailed modal shift analysis aimed at reshaping the transport system in a sustainable manner. This process is described within the context of strategic transport planning at county and regional levels, and continuing work on the theory and applications of the AIs is outlined.
Parking Requirements and Housing Affordability: Case Study of San Francisco
Authors: Jia Wenyu , Wachs Martin
Published: April 2007

Residential parking requirements specify the number of parking spaces that must be provided when new residential units are built. How these parking requirements influence housing affordability is examined. The provision of parking spaces requires land, building materials, and equipment, which increase the price of housing. On the other hand, it is a common belief that off-street parking requirements prevent streets from being overcrowded with parked cars. In a case study of six neighborhoods in the city of San Francisco, the influence on housing affordability of code-required parking was studied. A hedonic model was fit to data that described housing and neighborhood characteristics to explain statistically the sales price of housing units that changed hands in those neighborhoods in 1996. The analysis revealed that single-family houses and condominiums were more than 10 percent more costly if they included off-street parking than if they did not. Based on the selling prices and the distribution of incomes of San Francisco residents, it was estimated that tens of thousands of additional households could qualify for home mortgages for units without off-street parking if those units could be provided legally under zoning and subdivision ordinances. The policy implications of this finding include the possible consideration of alternative forms of regulation pertaining to the provision of off-street parking in residential projects.
Effects of Heavy-Vehicle Mechanical Condition on Road Safety in Quebec
Authors: Gou Michel , Clément Bernard , Birikundavyi Salvator , Bellavigna-Ladoux Olivier , Abraham Erick
Published: April 2007

A 2-year study was conducted of the effect of heavy-vehicle mechanical condition on road safety in the province of Quebec, Canada. The results in this summary include an evaluation of the effect of an existing annual heavy-vehicle mandatory mechanical inspection program (MMIP) on road safety and its effectiveness in improving heavy-vehicle mechanical condition. The effect of various mechanical components on road safety and the importance of their periodic inspection also are analyzed. Among the main findings were ( a) heavy-vehicle mechanical condition is responsible for 10 to 20 percent of accidents involving this type of vehicle in Quebec; ( b) if older vehicles (12 years or more) are not taken into account, the MMIP seems to prevent accidents caused by mechanical defects for a subsequent period of 2 to 3 months; ( c) the MMIP is not fulfilling its mandate adequately, because the observed frequency of heavy vehicles with noncomplying mechanical components is high, independent of the elapsed period since the last MMIP; ( d) heavy vehicles affected by major noncomplying components have a propensity to be involved in accidents that is five times higher than that of complying vehicles; ( e) the braking system is the most affected by major noncomplying components; ( f) the braking system comes in first when the dangerousness of mechanical components is considered, followed by tires, chassis, and steering system; ( g) the inspection program is not equally effective in identifying defect locations; ( h) heavy vehicles are responsible for 46 percent of the accidents in which they are involved; ( i) pretrip inspections appear to be the ideal complement to the MMIP in preventing accidents caused by mechanical defects. Based on these findings, recommendations are made on the inspection program, the data, and braking system maintenance to improve the mechanical condition of heavy vehicles and to reduce accidents caused by mechanical defects.
Reusable High-Molecular-Weight, High-Density Polyethylene Crash Cushions for Wide Hazards
Authors: Carney John F. , Alberson Dean C. , Lance Bullard D. , Chatterjee Subhasish , Menges Wanda
Published: April 2007

The development and full-scale crash testing of a new, reusable, and essentially maintenance-free crash cushion designed to shield wide hazards are described. The energy-dissipating medium in this device is composed of high-molecular-weight, high-density polyethylene cylinders. This “smart” energy-dissipating thermoplastic is the same material used in the REACT family of narrow-hazard crash cushions and truck-mounted attenuators. It is self-restorative and reusable and possesses excellent energy-dissipation properties. The design process incorporated the results of impact testing with individual polyethylene cylinders, finite-element modeling, and a comprehensive full-scale crash testing program conducted in accordance with the guidelines of NCHRP Report 350. It is demonstrated that finite-element modeling is a cost-effective tool whose use can minimize the number of costly full-scale crash tests required to develop an effective impact attenuation device. This new, reusable, wide-hazard crash cushion satisfies all of the requirements of NCHRP Report 350 and has been accepted by FHWA for use in the National Highway System.
Development of a Flared End Terminal That Meets Criteria of NCHRP Report 350: The REGENT System
Authors: Denman Owen S. , Welch James B.
Published: April 2007

A project to develop a flared guardrail end terminal system that would meet NCHRP Report 350 Test Level 3 (100 km/h) requirements was initiated at the request of a group of small guardrail manufacturers that did not have access to such a system. This was a major concern to this group that needed to have access to such a system before the October 1998 Intermodel Surface Transportation Efficiency Act of 1991 implementation date for NCHRP Report 350 roadside hardware. A set of design, performance, and cost objectives was established, and a decision was made to qualify the system for both weak and strong soils. The development project resulted in a new type of design and specifications for the wood posts used in the end terminal section. The redirective and gating end terminal (REGENT) system was designed and tested to meet the conditions described in NCHRP Report 350 (Test Level 3) and was approved for use on the National Highway System by FHWA. The REGENT system was tested when it was attached to both wood and steel downstream guardrail posts.
Effects of Post and Soil Strength on Performance of Modified Eccentric Loader Breakaway Cable Terminal
Authors: Patzner Greg S. , Plaxico Chuck A. , Ray Malcolm H.
Published: April 2007

The effects of wood post strength and soil strength on the dynamic performance of guardrail systems have long been a concern of the roadside safety community. Evidence from full-scale crash tests has suggested that these parameters may significantly affect guardrail system performance. Essentially identical tests have resulted in widely varying outcomes that might be the result of various post strengths and soil conditions. A finite-element model of a common guardrail terminal—the modified eccentric loader breakaway cable terminal—was developed to examine the effects of post strength and soil strength on the overall performance of the terminal system. A matrix of 12 simulations of a particular full-scale crash test scenario was conducted with the explicit nonlinear dynamic finite-element software LS-DYNA3D to establish the combinations of post and soil strengths that produce favorable results. The parametric simulations show that certain combinations of soil and post strengths increase the hazardous possibilities of wheel snagging, pocketing, or rail penetration, whereas other combinations produce more favorable results. Conditions that will maximize the safety and reliability of the guardrail terminal system are identified.
User Requirements and Willingness To Pay for Traffic Information Systems: Case Study of Sydney, Australia
Authors: Kim K.S. , Vandebona U.
Published: April 2007

The field of information provision to motorists has seen remarkable technological innovations in recent years. These techniques are generally classified under advanced traveler information systems (ATISs). These systems are designed to bring travel time savings and congestion alleviation to commuters. In the context of determining who will use this information system, what types of information are required, and how traffic information affects traveler behavior, the user needs and preferences derived from a survey of commuters in Sydney, Australia are described. The attitudinal survey has examined driver attitudes toward radio traffic information systems in particular. It is seen that drivers thought of radio traffic information systems as generally accurate. Drivers revealed that information on dynamic conditions such as traffic entities and road accidents is more desired than information on relatively static conditions such as alternative routes. On the aspect of technology preference, radio has overwhelming support as the preferred delivery system compared with computers and telephones. The results of an analysis of willingness to pay for information are similar to findings from overseas. This particular analysis has been based on an ordered probit model that shows the significance of information system attributes and commuter demographics.
Flintshire Bridge [Pont Sir Y Fflint], Wales: Design Aesthetics and Innovation
Authors: Hollinghurst Edmund
Published: April 2007

Acclaimed winning design of the competition to devise the new River Dee crossing, the landmark Flintshire Bridge in Wales, United Kingdom, opened on March 6, 1998, by Her Majesty the Queen, defines new levels of excellence in engineering design and technology. A long-span, cable-stayed asymmetric concrete structure, it represents a radical resolution of major environmental, aesthetic, and technological problems, resulting in significant advances in the techniques of modern bridge building. A demonstration of the state of the art in civil engineering, it has won local and national praise. The impact of the use of concrete in relation to aesthetics, engineering, and architecture is discussed, in particular the use of a project as a pilot scheme for the development of a new specification for internally grouted posttensioned concrete following the collapse of a bridge in Wales due to corrosion. The innovation relating to the inherent instability of parallel strands (stay cables) in rain and light wind is discussed, together with the resulting innovations to overcome associated problems.
Tests of Large Girders Treated To Enhance Fatigue Strength
Authors: Takamori Hiroyuki , Fisher John W.
Published: April 2007

Two large-scale fatigue test studies of plate girders are reported on. One study involved a series of coverplated bridge girders with small fatigue cracks that were retrofitted in 1976 as described in NCHRP Report 206. The second study involved plate girders fabricated from HPS-485W (HPS-70W) steel with welded attachments. The Category E’ coverplated beams that were removed from the I-95 Yellow Mill Pond Bridge in 1997 had been retrofitted in 1976 by either air hammer peening or gas tungsten arc (GTA) remelting. All details had small fatigue cracks at the time of retrofit. No further fatigue cracking was observed at the coverplate ends after 20 years of service and an estimated 56 million truck passages. The beams were tested at a stress range of 69 MPa (10 ksi). Cracks developed from the root of the transverse end weld and propagated through the weld throat. The fatigue resistance of the treated weld toe details improved to Category C except for one GTA-remelted detail, which exceeded Category D. Another study was carried out on large-scale HPS-485W plate girders with as-welded and ultrasonic-impact treatment (UIT) details. UIT was applied to the weld toe of transverse stiffeners welded to the web and flanges (Category C) and to coverplated ends (Category E’). The as-welded details cracked at their expected fatigue resistance. The UIT transverse stiffeners improved to Category B fatigue resistance, whereas the UIT coverplated details improved to Category C fatigue resistance.
Fitness-for-Purpose Evaluation of Bridges Using Health Monitoring Technology
Authors: Heywood Rob , Roberts Wayne , Taylor Ray , Andersen Ryan
Published: April 2007

Evaluation of in-field performance of bridges is dependent on many assumptions. Those associated with the analytical model (boundary conditions, influence of curbs, membrane action, the model, etc.) and the resistance model (material properties, condition, fatigue damage, etc.) are commonly recognized as the sources for the differences between theoretical strength and in-service strength as demonstrated by proof load testing worldwide. Likewise there are many assumptions associated with the loading model and the related load factors. Bridge health monitoring technology is providing the opportunity to monitor the in-service performance of bridges. A methodology is presented for undertaking a fitness-for-purpose evaluation (FPE) of bridges based on health monitoring and theoretical data. The methodology is set in the context of limit state codes and illustrated by four case studies, two from Australia and two from New Zealand. Each of the bridges is steel, lowly rated theoretically, and located on relatively low-trafficked routes. The outcome of the FPEs indicates that the structures are safe to remain in service under current loading conditions although interventions are suggested in the relatively short term. Health monitoring was also able to identify the reasons for the significant differences between the theoretical and the health monitoring results. Many of the reasons are related to the specific loading conditions at the site and could not readily have been identified using theoretical approaches, behavioral testing, or proof load testing. Although this technology has its limitations, it is providing better information for those involved in the decision-making process and helping to target actions based on risk.
Design and Construction of a Cable-Trussed Girder Bridge
Authors: Mochizuki Hidetsugu , Hanada Katsuhiko , Nakagawa Tomokazu , Hanawa Youji , Yamagiwa Ichiro , Yasuda Katsunori , Fujino Yozo , Nagai Masatsugu
Published: April 2007

Takehana No. 3 Bridge is a cable-trussed girder bridge constructed on a highway route in Shikoku Island, Japan. This is the first application of a cable-trussed girder bridge to a highway bridge in Japan. The cable-trussed bridge (or reversed cable-stayed girder bridge) consists of relatively slender steel plate I-girders, a spatial frame-type post arranged beneath the girders at the middle of the span, and external cables anchored at the ends of the girders. The structural details, static and dynamic characteristics, and design and construction of the bridge are presented. In addition, the efficiency of this type of bridge is emphasized.
Innovative Design and Construction of Chesapeake and Delaware Canal Bridge
Authors: Pate W. Denney
Published: April 2007

An outstanding accomplishment of bridge design, construction, and management, the Chesapeake and Delaware (C&D) Canal Bridge demonstrates that precast, segmental, cable-stayed bridges can be an economical and aesthetically pleasing solution in an area of the country where steel bridges are predominant. The C&D Canal Bridge is the first major concrete segmental cable-stayed bridge structure to be completed in the Northeast. The $58 million C&D Canal Bridge is a precast concrete, segmental structure 1417 m (4,650 ft) in length. Twin parallel box girders were designed to provide six lanes of travel with a total bridge width of 38.7 m (127 ft), with each precast box girder containing three 3.65-m (12-ft) lanes and two 3-m (10-ft) shoulders. Innovative construction techniques, economy, and aesthetics were the primary focus of the construction and design solutions used for the 229-m (750-ft) cable-stayed main-span crossing. The bridge was completed on schedule, with no claims or suits, at a cost slightly under the original bid. A quality-based selection process for the bridge designer, a prequalification process for the selection of the contractor, a disputes review panel, and informal partnering during construction all contributed greatly to a very successful project. The use of precast concrete elements provided an efficient and time-saving technique for the construction of this bridge. In addition, precast concrete box girders, box piers, and delta frames were designed to anchor the cable stays and make the parallel trapezoidal box girders monolithic throughout the main span.
Influence of Elastomeric Bearings on Traffic-Induced Vibration of Highway Bridges
Authors: Kawatani Mitsuo , Kobayashi Yoshikazu , Kawaki Hideaki
Published: April 2007

Elastomeric bearings (rubber bearings) have been used in highway pseudo-continuous bridges without joints changed from simple girders to reduce the environmental influence of traffic-induced vibration. In addition, elastomeric bearings have been adopted in simple girder bridges for base isolation systems of earthquakeproof structures. Three-dimensional analysis of dynamic response of bridges under moving vehicles is carried out to examine the change of dynamic response in bridges caused by replacing steel bearings with elastomeric bearings. Analytical results are compared with experimental results in urban highway bridges. It is not shown clearly in experiments that natural frequencies are changed slightly in analysis by replacing steel with elastomeric bearings. Although vertical displacements of main girders at the span center do not almost change between steel and elastomeric bearings, horizontal displacement in the bridge axis direction becomes larger with elastomeric bearings. For the evaluation of the experimental acceleration of the ground motion, the dynamic reaction force is analyzed and the dynamic influence is investigated.
In-Service Performance of High-Performance Concrete Bridge Decks
Authors: Alampalli Sreenivas , Owens Frank
Published: April 2007

The current statewide standard for New York State bridge decks is Class HP (high-performance) concrete. This mix was introduced in April 1996 to increase deck durability by reducing cracking and permeability. Since its introduction, more than 80 bridge decks have been built with Class HP concrete. To compare the performance of Class HP concrete with that of previously specified concrete, the decks were visually inspected. Results indicated that Class HP decks performed better than previously specified concrete in resisting both longitudinal and transverse cracking. Furthermore, of the 84 decks inspected, 49 percent exhibited no cracking at all, but of those that had cracked, 88 percent exhibited equal or less longitudinal cracking and 80 percent exhibited equal or less transverse cracking than previously specified concrete. A final result showed that average transverse crack density on Class HP decks, excluding uncracked decks, was 6.9 cm/m2. This value is comparable with crack densities for other decks (not using HP mix) that were reported in recent literature.
Highway Bridge Seismic Design: How Current Research May Affect Future Design Practice
Authors: Friedland Ian M. , Mayes Ronald L. , Yen W. Phillip , O’Fallon John
Published: April 2007

Under several contracts sponsored by FHWA, the Multidisciplinary Center for Earthquake Engineering Research has been conducting a research program on highway structure seismic design and construction. Among its objectives, the program studies the seismic vulnerability of highway bridges, tunnels, and retaining structures and develops information that could be used, in the case of bridges, to revise current national design specifications. A specific requirement of the program is to have research results independently reviewed and assessed to determine the impact they may have on future seismic design specifications for highway structures. Some of the important results of the research that has been conducted under the program are summarized, and issues that resulted from this impact assessment about expected changes in future seismic design practice of highway bridges are discussed.
Scour Countermeasures Using Geosynthetics and Partially Grouted Riprap
Authors: Heibaum Michael H.
Published: April 2007

The main requirement of any scour countermeasure or scour protection measure is to prevent erosion, so a top layer has to be built that is sufficiently resistant against the hydrodynamic loads and that protects the subsoil. Single elements have to be large enough to withstand the scouring forces and require an appropriate layer thickness. Smaller, mutually connected elements allow for a moderate layer thickness but provide the same resistance. To avoid excess water pressures below the top layer, permeable systems are recommended. A very reliable system is partially grouted riprap, which meets all the requirements of strength, flexibility, and permeability. Permeable systems need a well-designed filter. Placement of a grain filter or a geotextile filter is complicated by the current, so special equipment is needed. In mild currents a “sandmat” (a sand-filled nonwoven geotextile) can be used. In stronger currents use of geosynthetic geocontainers is proposed to achieve both a high resistance against the current and a well-performing filter.
Using Pavement Management System Concepts to Determine the Cost and Impact of Utility Trenching on an Urban Road Network
Authors: Lee Stephen Q.S. , Lauter Katherine A.
Published: April 2007

The results are presented from a 2-year study on the impact of utility trenching on urban flexible road network pavement roughness, pavement surface distress, structural carrying capacity, pavement life cycle, rehabilitation and maintenance requirements, and the costs associated with these impacts in Ottawa-Carleton, Canada. Included are the pavement performance and life-cycle relationships developed using modified methodologies to address concerns raised by reviews carried out by Construction Technology Laboratories Inc. and the National Research Council of Canada on utility trenching studies to date. In this study, normalized individual pavement section life cycle, a composite pavement quality indicator, and performance prediction models calibrated with numerous years of field data were used in the life-cycle and pavement performance determination. These modifications made to the conventional pavement management system when used to determine the impact of utility trenching are shown to provide performance and life-cycle relationships with better correlation than algorithms used in the previous studies. In this study, very high coefficients of determination ( R2) of 0.79 to 0.85 were obtained for the pavement performance and life-cycle relationships regressed from field data for quantification of urban road network pavement with and without the impact of utility trenching. The factors and costs associated with the impact of utility trenching, such as reduction in pavement life cycle, additional cost for subgrade base repair, pavement strengthening requirements from loss of fatigue structural carrying capacity, and the additional area affected beyond the trenched area, are also quantified in this study.
Forecasting of Pavement Crack Performance with Adaptive Filter Model
Authors: Lou Zhenyu , John Lu Jian , Gunaratne Manjriker , Dietrich Bruce
Published: April 2007

The capability to forecast pavement crack performance has been identified as a critical pavement management system (PMS) need. In particular, crack performance forecasting can support proactive pavement management strategies. However, previous attempts at developing crack forecasting models have met with limited success. Because of the complexity of the pavement crack progression mechanism over time, a dynamic forecasting model could be more appropriate as opposed to static forecasting models. The results of a research effort to develop an adaptive filter model to forecast a pavement crack index for Florida’s highway network are summarized. The concept of the adaptive filter model is introduced along with its mathematical algorithm and modeling procedure. The adaptive filter model, which was developed with field data collected from Florida’s highway network, is able to dynamically forecast crack performance on the basis of historical crack performance data. For the purpose of model evaluation, the adaptive filter model was compared with the traditional autoregressive (AR) model. According to the comparison results, the adaptive filter model had significantly lower errors as compared with the AR model, demonstrating better forecasting capability. The adaptive filter model was more responsive to unexpected changes in pavement performance than the AR model. Given these advantages, it appears that such an adaptive filter model may have considerable potential for use in PMS applications.
Evaluation of Accuracy of Surface Profilers
Authors: Fernando Emmanuel G.
Published: April 2007

The Texas Department of Transportation (TxDOT) is implementing smoothness specifications based on profilograph testing as part of its construction quality control/quality assurance (QC/QA) program. Automated California-type profilographs are now used in most tests, in which the equipment is pushed over a prescribed wheelpath. It appears that smoothness specifications will continue to be based on the profilograph, at least for the short term. However, in view of advances in profiling technology, it becomes prudent to investigate other methods of measuring surface profiles and to develop smoothness specifications based on profilers that offer greater accuracy and higher production rates. In pursuit of its goal of providing smooth pavements, TxDOT initiated a research project with the Texas Transportation Institute to develop a smoothness specification for asphalt concrete overlays based on the new generation of pavement profilers, which offer greater accuracy in profile measurement relative to the profilographs now used in construction projects. Among other things, this research project evaluated a number of profile-measuring devices to establish the availability of equipment for implementing a new profile-based smoothness specification in Texas. This evaluation showed that lightweight profilers provide a basis for developing and implementing smoothness specifications that are based on surface profile. Since surface smoothness is commonly monitored using inertial profilers in pavement condition surveys conducted for pavement management, having the initial profile allows highway agencies to tie the as-built smoothness to the rest of the performance history and thus maintain a consistent historical record of surface smoothness throughout the pavement life cycle.
Laboratory Calibration and In Situ Measurements of Moisture by Using Time-Domain Reflectometry Probes
Authors: Diefenderfer Brian K. , Al-Qadi Imad L. , Loulizi Amara
Published: April 2007

Excessive moisture in pavement systems can cause considerable damage and can lead to early deterioration. One method for continually monitoring the moisture content of pavement systems nondestructively is the use of time-domain reflectometry (TDR) probes. Although originally developed to measure faults in electrical cables, TDR probes employ an electromagnetic wave that is transmitted along a set of metallic conducting rods (or waveguides). The velocity of the electromagnetic wave is influenced by the dielectric constant (ϵ) of the material surrounding the waveguides. The large contrast between the dielectric constants of free water and of dry soil makes this an effective nondestructive evaluation method. Soil samples with different moisture contents were prepared and the TDR output, which is a function of the dielectric properties, was compared with the measured gravimetric moisture content. Calibration equations were developed in a laboratory setting for two types of TDR probes (CS610 and CS615) embedded in the Virginia Smart Road test facility at Blacksburg, Virginia. Preliminary field data were collected for the two different probe types embedded in different pavement structures. It is shown that the two types of TDR probes yield similar data in some situations and different data in other circumstances. It appears that the composition of the pavement structure has an effect on the moisture measured in the subbase layer. Although preliminary results indicate that the use of CS615 TDR probes in pavement applications is promising, further continuous monitoring of both types of TDR probes is necessary to determine if the CS615, which can be readily connected to a data acquisition system, can be used in lieu of the CS610, which requires a time-consuming collection procedure or possible additional data collection equipment.
Sustainable Highway Development in a National Park
Authors: Morrall J.F. , McGuire T.M.
Published: April 2007

Sustainable highway-engineering improvements have been developed or adopted to mitigate the unique environmental impact that highways and roads have in Canadian Rocky Mountain National Parks, which are also World Heritage Sites. Three levels of sustainable highway development are presented. The first is the reconstruction or rehabilitation of park roads. Examples are presented from several national parks in which parkways and low-volume roads were reconstructed or repaired in ways that reduced impacts. The second is the development of the passing-lane system on the Trans-Canada Highway in the Rocky Mountain National Parks. The passing-lane system has extended the design service life of the two-lane highway by approximately 15 years while maintaining an acceptable level of service. The third example is the twinning of 18.6 km of the Trans-Canada Highway, which represents a logical next step in a program of sequential twinning following the passing-lane phase. Discussion includes the ways in which highway-engineering improvements were developed to address and mitigate numerous potential project impacts that were identified during environmental assessment. Included in the environmental mitigations were a series of measures such as fencing, animal-crossing structures, and underpasses to address wildlife movement, biodiversity, and mortality. Stream, terrain, and vegetation disturbance-minimization techniques also were applied. Research has found that the mitigation measures have been effective in reducing wildlife–vehicle collisions by as much as 97 percent.
Using Theoretical Models to Design Low-Noise Wheels and Track
Authors: Thompson D.J. , Jones C. J.C.
Published: April 2007

The main source of railway noise is the rolling of the steel wheel on the steel rail. Theoretical models of the phenomenon have been under development since the 1970s, culminating in the Track-Wheel Interaction Noise Software (TWINS). Using the TWINS model, it is possible to evaluate the rolling-noise behavior of different wheel and track designs and thereby derive new designs that are inherently quieter. An overview is given of the mechanisms involved in noise generation and the parameters that have the most influence on the noise are identified. It is usually important to reduce the noise from both the wheel and the track. Some examples are given of techniques that are being developed using the model with the aim of reducing the noise at the source.
Investigation of Tire-Road Noise Levels for Ohio Pavement Types
Authors: Herman Lloyd A. , Ambroziak Matt J. , Pinckney Elvin
Published: April 2007

Tire-road noise levels for Ohio Department of Transportation pavement types were investigated to provide an additional criterion for pavement selection in noise-sensitive areas. Tire-road noise measurements were conducted in accordance with the International Organization for Standardization’s statistical pass-by method (ISO 11819-1)—the first use of this standard in the United States. A statistical pass-by index (SPBI) was determined for each pavement test, which enabled the ranking of the pavement types according to tire-road noise levels, as well as a means of comparing results with other studies conducted according to the standard. There was a difference of 6.7 dB between the lowest (open-graded asphalt) and the highest (random-transverse-grooved concrete) SPBI for all of the pavements measured. Additionally, the data were analyzed to produce reference energy mean emission levels for future use with traffic-noise prediction modeling.
Airport Infrastructure Management with Geographic Information Systems: State of the Art
Authors: McNerney Michael T.
Published: April 2007

The widespread application of geographic information systems (GISs) at airports is detailed through surveys of U.S. airports. A recent survey conducted through the Airport GIS Committee of the American Association of Airport Executives indicated that more than 60 percent of airports use GISs or plan to use GISs within the next 3 years. The application of GISs for infrastructure management, environmental analysis, and airport operations is becoming commonplace at larger U.S. airports. Integration of infrastructure management in general and pavement management in particular with airportwide GISs provides far greater management capabilities than traditional infrastructure management systems. The development of integrated airport GISs and the availability of affordable, differentially corrected Global Positioning System receivers have resulted in a paradigm shift in methods of infrastructure management. As the new millennium approaches, the state of the art in infrastructure and pavement management is turning away from the traditional forms toward map-based systems that have sophisticated analytical tools. In the case of pavement management, the use of map-based analysis will overcome many of the shortcomings of the traditional MicroPAVER inspection process. The capabilities of the current state of the art in pavement management are detailed.