bluuebunny/crossref_metadata_2025 huggingface dataset:
Driving Simulators for Evaluation of Novel Traffic-Control Devices: Protected–Permissive Left-Turn Signal Display Analysis
Authors: Noyce David A. , Smith Christopher R.
Published: April 2007

A study evaluated drivers’ comprehension of several experimental five-section protected–permissive left-turn (PPLT) signal displays. A full-scale driving simulator and static driver study were used. Study methods were compared while evaluating drivers’ comprehension and response to various combinations of five-section PPLT signal-display arrangements (horizontal, vertical, and cluster) and permissive left-turn indications (green ball, flashing red ball, flashing yellow ball, flashing red arrow, and flashing yellow arrow). The results showed that the type of five-section PPLT signal display arrangement has very little effect on driver comprehension of the permissive left-turn maneuver. The type of permissive indication used in five-section PPLT signal displays had a significant effect on driver comprehension, since the green ball, flashing yellow ball, and flashing yellow arrow were the best understood. When combining five-section PPLT signal-display arrangements and permissive indications, the five-section horizontal arrangement with a flashing-yellow-ball permissive indication had the highest level of driver comprehension. The lack of surrounding driving cues in the static driver study led to significantly higher fail-critical (serious) response rates. The green-ball permissive indication had a driver comprehension rate over 30% lower in the static study, clearly showing that drivers do not correctly comprehend the meaning of the green ball (assume it is protected) and use other information to make left-turn decisions while driving. The findings of this research show that driving simulation provides an effective study method and effectively replicates the actual driving environment. Simulators should be considered when conducting driver comprehension analyses.
Detection and Identification of Light-Emitting Diode Traffic Signals by Protan Observers
Authors: Huang Michelle Kun , Bullough John D. , Boyce Peter R. , Bierman Andrew
Published: April 2007

Protan observers have lower spectral sensitivity than color-normal observers at long wavelengths of the visible spectrum. Responses of protan and color-normal subjects to light emitting diode (LED) and incandescent traffic signals of red and yellow nominal color during simulated daytime viewing conditions are described. Reaction times, missed signal percentages, and color-identification accuracy were measured. The results indicate that for protans, detection performance to red LED signals was enhanced when the dominant wavelength was moved toward shorter wavelengths, but this shift also appeared to decrease their ability to correctly identify the signal color. Although the yellow LED signal used in this study provided similar detection performance for protans as a yellow incandescent signal, its dominant wavelength was sufficiently long for it to sometimes be confused with red. In general, the results of this study are consistent with the 1994 recommendations of the Commission Internationale de l’Éclairage for signal colors to be seen by color-normal and protan observers. Nonetheless, neither detection nor color identification for protans approached that of color-normal observers.
Nighttime Expert Panel and Photometric Evaluations of Unlighted Overhead Guide Signs
Authors: Zwahlen Helmut T. , Russ Andrew , Vatan Şahika
Published: April 2007

A nighttime field evaluation of four different retroreflective overhead-sign sheeting combinations (ASTM D4956 beaded Type III legend on beaded Type III background, Type IX legend on beaded Type III background, Type IX legend on Type IX background, and Type VII legend on beaded Type III background) was conducted on a section of US-30 near Mansfield, Ohio. The test-material combinations were compared when lighted and unlighted (illuminated by low-beam headlights only). Twelve Ohio Department of Transportation engineers and technicians served as evaluators, riding the test loops in 2002 Dodge Caravans. The white Type IX legend on green-beaded Type III background sheeting combination received the highest evaluation scores for appearance, conspicuity, and legibility. The scores for the Type VII legend on beaded Type III background signs were only slightly lower in all three categories. The Type IX legend on Type IX background combination received slightly lower evaluation scores, and the beaded Type III legend on beaded Type III background combination received the lowest evaluation scores. The same signing material combinations were also photometrically (luminance and luminance contrast ratio) evaluated under low-beam illumination at selected approach distances from 200 to 1,000 ft (61 to 305 m) using a 1984 Peterbilt truck, a 2002 Chrysler Town and Country minivan, and a 2002 Toyota Camry sedan, both when lighted and unlighted (low beams). Unlighted overhead signs made with either the white Type VII or the Type IX legends on green-beaded Type III backgrounds provide nighttime motorists with adequate appearance, conspicuity, and legibility.
Reductions in Traffic Sign Retroreflectivity Caused by Frost and Dew
Authors: Hildebrand Eric D.
Published: April 2007

A study of in-service traffic signs was undertaken to quantify the average effects of frost and dew on their retroreflective capabilities. The results were then compared with proposed minimum retroreflectivity standards recently developed by FHWA-sponsored research for inclusion in the Manual on Uniform Traffic Control Devices. Although the effects of frost and dew were found to be variable, average reductions in retroreflectivity levels of 79% and 60%, respectively, were found. None of the different colored signs sampled with Type I (engineering grade) sheeting was found to meet the proposed minimum levels when covered in frost or dew (with the exception of signs with white backgrounds covered in dew), even though all signs were in like-new condition. Signs sampled with Type III (high intensity) sheeting had mixed results. The findings are significant enough that they should be considered in the development of the final version of the FHWA national standards. Furthermore, those jurisdictions subject to frequent cycles of frost and dew should review usage guidelines governing the grade of sign materials used, allowing for expected loss of retroreflectivity.
Effect of Variable-Message Signs in Reducing Railroad Crossing Impacts
Authors: Sivanandan R. , Dion Francois , Rakha Hesham , Van Aerde Michel
Published: April 2007

At-grade highway–railroad crossings cause traffic control problems that have a bearing not only on traffic safety but also on traffic flow efficiency. Crossings located near freeway exits pose particularly acute problems, as long closures could result in vehicle queues that spill back onto freeway lanes. A potential solution to this problem was evaluated by investigating the use of variable message signs to divert exiting freeway traffic through non-congested alternate exits. This was done using the crossing near the Fredericksburg Road exit on Interstate 10 (I–10) in San Antonio, Texas, as a case study. In the evaluation, microscopic simulation was used to determine the impacts of train operations at the crossing and the potential benefits of a variable-message sign (VMS) system installed on I–10. These effects were gauged by considering scenarios with varying levels of train duration, traffic demand on the freeway exit, and driver compliance to the displayed messages. While little network improvements were obtained, the analysis demonstrates the capability of the INTEGRATION software in analyzing such scenarios and the extent to which exiting freeway traffic may benefit from the VMS system, as well as the need to consider fuel consumption and vehicles emissions in the evaluations.
Structural Evaluation of Precast Concrete Channel Beams in Bridge Superstructures
Authors: Durham Stephan A. , Heymsfield Ernest , Schemmel John J.
Published: April 2007

During the period from the mid-1950s through the mid-1970s a large number of bridges were constructed throughout Arkansas using a 5.79-m (19-ft) long, precast, non-prestressed, concrete channel beam that was then standard. A survey of highway departments has identified 12 states that have used a similar bridge element in the past. It has been determined that nearly 400 of these bridges remain in use in Arkansas alone. Recently, the Arkansas State Highway and Transportation Department discovered that a number of these sections are exhibiting potentially serious deterioration. The deterioration appears to have been initiated by corrosion of the flexural reinforcement in the beam stems. An additional issue is that these beams were fabricated without any shear reinforcement. Moreover, some sections are showing signs of concrete degradation. The need to determine the in-place load capacity, serviceability, and durability of these sections has reached a critical level. To date, 20 beams have been removed from existing structures and tested for their flexural load capacity and the material properties of the concrete and longitudinal reinforcement. Results have varied depending on the extent of deterioration. However, in nearly every case shear failure has controlled the load capacity of a section. Based on this research, a draft field guide, intended for use by inspection crews, is being prepared. This guide will aid inspectors in prioritizing sections for repair, rehabilitation, and removal.
Application of Nondestructive Evaluation to Subway Tunnel Systems
Authors: Delatte Norbert , Chen Shen-en , Maini Nitin , Parker Neville , Agrawal Anil , Mylonakis George , Subramaniam Kolluru , Kawaguchi Akira , Bosela Paul , McNeil Sue , Miller Richard
Published: April 2007

Subway tunnel condition assessment presents significant challenges for engineers and managers and is becoming increasingly important as the systems continue to age. Tunnels are in constant heavy use in an aggressive environment. Tunnel systems are vast, dark, and noisy. The national investment in subway tunnels is enormous, and careful maintenance and management are necessary to protect this investment. Technologies that can rapidly and accurately access the condition of subway tunnels without interfering with the normal operation of the system were studied. First, issues and problems in subway tunnel maintenance were reviewed through the literature and by interviewing transit agency managers and engineers. Next, different nondestructive evaluation (NDE) methods including spectral analysis of surface waves, impact echo, ground-penetrating radar, and impulse response were evaluated to determine the advantages and limitations of these methods on different problems like water leakage, corrosion, and cracks in subway tunnel systems. Issues of data and infrastructure management were also considered. NDE technologies have considerable potential for improving the maintenance and management of transit infrastructure. However, to fully realize that potential, further development is needed. It is necessary to distinguish between methods that require interruption of subway traffic from those that do not. Rapid screening NDE methods must be researched to develop clear signals of delamination, moisture-related damage, and other issues of concern. It is also necessary to develop automated procedures to process the vast amounts of data generated during extensive NDE testing. Case studies and demonstration projects must be developed and documented to convince managers of the utility of this approach.
Time Domain Reflectometry for Void Detection in Grouted Posttensioned Bridges
Authors: Chajes Michael , Hunsperger Robert , Liu Wei , Li Jian , Kunz Eric
Published: April 2007

The presence of voids is a serious problem in grouted posttensioned bridges because voids greatly reduce the corrosion-protective capabilities of the grout. Current methods for void detection suffer several significant drawbacks. A new method utilizing time domain reflectometry (TDR) is discussed. TDR is a well-developed method for detecting discontinuities in electrical transmission lines. A recent study has indicated that TDR can be used as an effective nondestructive damage detection method for concrete bridges. A void changes the electrical properties of transmission lines and therefore introduces electrical discontinuities. It can be detected and analyzed by TDR. Experiments on short specimens that are used to model grouted posttensioning ducts with built-in voids have been conducted and demonstrate the potential of TDR as a void detection method.
Structural Performance of Fiber-Reinforced Polymer Honeycomb Sandwich Panels: Evaluation of Size Effect and Wrap Strengthening
Authors: Kalny Ondrej , Peterman Robert J. , Ramirez Guillermo , Cai C. S. , Meggers Dave
Published: April 2007

Stiffness and ultimate load-carrying capacities of glass fiber-reinforced polymer honeycomb sandwich panels used in bridge applications were evaluated. Eleven full-scale panels with cross-section depths ranging from 6 to 31.5 in. (152 to 800 mm) have been tested to date. The effect of width-to-depth ratio on unit stiffness was found to be insignificant for panels with a width-to-depth ratio between 1 and 5. The effect of this ratio on the ultimate flexural capacity is uncertain because of the erratic nature of core-face bond failures. A simple analytical formula for bending and shear stiffness, based on material properties and geometry of transformed sections, was found to predict service-load deflections within 15% accuracy. Although some factors influencing the ultimate load-carrying capacity were clearly identified in this study, a reliable analytical prediction of the ultimate flexural capacity was not attained. This is because failures occur in the bond material between the outer faces and core, and there are significant variations in bond properties at this point due to the wet lay-up process, even for theoretically identical specimens. The use of external wrap layers may be used to shift the ultimate point of failure from the bond (resin) material to the glass fibers. Wrap serves to strengthen the relatively weak core–face interface and is believed to bring more consistency in determining the ultimate load-carrying capacity.
Model for Evaluating Cost-Effectiveness of Retrofitting Railway Bridges for Seismic Resistance
Authors: Day Kevin R. , Barkan Christopher P. L.
Published: April 2007

Many of the major railroad lines in the Mid-America earthquake region are potentially susceptible to high peak ground accelerations (PGA) and soil liquefaction effects due to an earthquake associated with the New Madrid fault. With geographic information systems (GIS) data and analysis techniques, the risk to the rail network posed by a major earthquake in the region was estimated. It was estimated that about 2,107 active rail route miles and 2,082 railroad bridges, including eight major river-crossing bridges over the Ohio and Mississippi Rivers, are in areas with a 2% probability of experiencing PGA values with potential to cause moderate to severe damage (>20% g) in the next 50 years. Because of the importance of this portion of the rail network and the bridges in the region, a model to calculate the cost-effectiveness of retrofitting railway bridges for enhanced seismic resistance was developed. Analysis using the model indicates that retrofitting small to moderately sized bridges is not generally cost-effective in the Mid-America region. However, a sensitivity analysis indicated that for large river-crossing bridges there may be plausible conditions when retrofitting would be cost-effective.
Seismic Analysis and Displacement-Based Evaluation of the Brooklyn-Queens Expressway, New York
Authors: Dameron Robert A. , Arzoumanidis Serafim G. , Bennett Steven W. , Malik Ayaz
Published: April 2007

The Brooklyn–Queens Expressway (BQE), Interstate 278 between Atlantic Avenue and Washington Street in Kings County, is an approximately 1,500-m-long multiple-level highway reinforced concrete structure that was built in 1948. It is an important transportation link in the New York City metropolitan area and serves a daily traffic volume of 122,000 vehicles. The longest portion of the BQE consists of elevated one-, two-, and three-level cantilever structures. They are built into the hillside of Brooklyn Heights in successive levels, set back to provide light and air to three lanes of traffic in each direction. They have a unique configuration consisting of rigid frames supporting the roadways with long cantilevers, serving also as retaining walls supporting the hillside beneath adjacent brick buildings. The reinforced concrete portions of the BQE were modeled with finite elements that explicitly represented the concrete and reinforcement and used nonlinear material models. The displacement performance was determined in cyclic pushover analysis that predicted concrete cracking and reinforcing bar yielding. This performance was compared with recently developed displacement performance criteria to establish displacement capacities. The displacement demands were determined by time history analyses using nonlinear models. The methods and criteria that were used for evaluation of the BQE structures are described, and conclusions that may be applicable to future seismic evaluations using the displacement-based approach are provided. Other project challenges are also discussed, including the seismic effects of adjacent buildings and subway tunnels.
Nonmotorized Interference and Control Measures at Signalized Intersections in China
Authors: Wei Heng , Lu Feng , Hou Gang , Mogharabi Abi
Published: April 2007

The adverse effects of bicycles and pedestrians on motor vehicle traffic in at-grade, signalized intersections under mixed-traffic conditions have been observed at several typical intersections in Beijing. Mixed bicycle and motor vehicle traffic is a major characteristic of urban transport in China and has led to serious congestion and capacity reduction in at-grade signalized intersections in urban areas. A method is presented to quantitatively measure nonmotorized effects, and values are recommended for adjusting the model to estimate the capacity of through vehicle lanes. Several temporal segregation solutions to mixed-traffic problems in at-grade signalized intersections are described that have proven cost-effective in several Chinese cities, and suggestions for their application are provided.
Capacity Analysis Based on Theoretical and Practical Considerations
Authors: Wei Zhou , Sun Xiaoduan
Published: April 2007

China’s unprecedented development of freeway systems has been one of the largest infrastructure investments in the country’s recent history. Capacity analysis is key to the planning, construction, and classification of Chinese freeway systems. Incorrect capacity analysis could lead to either an overbuilt freeway system wasting valuable resources or an underbuilt freeway system that cannot meet the demand resulting from rapid economic development. A new method of freeway capacity analysis is presented that links the traffic flow model with highway safety requirements. The capacity derived from this method is theoretically sound and feasible in practice.
Unevenness of Intersection Pavement and Bicycle Safety
Authors: Koike Hirotaka , Morimoto Akinori , Kitazawa Atsushi
Published: April 2007

Bicycles are environmentally friendly and easy to operate. However, the bicycling environment in Japan is inadequate compared with many developed countries. Bicycle accidents have been increasing in recent years, and safety measures are needed to improve the bicycling environment. Although road surface conditions have improved, as reflected in the recent barrier-free policy for elderly and disabled pedestrians, an uneven surface between the road and the crosswalk can help to reduce accidents by reducing running speed. Because the most frequent type of bicycle accident is a collision with a car at an intersection, the accident-prevention potential of an uneven surface at an intersection crosswalk was examined. Students were asked to run along specific routes, and speed and vibration changes when they passed through intersections were measured. On the basis of the results, an analysis was made of what road environments would benefit from an uneven crossing surface. An uneven surface was found to reduce speeds at intersections with limited sight distance. However, other appropriate safety measures must be applied to reduce bicycle speed when an uneven crossing surface cannot be used because of the barrier-free policy.
Effects on Road Safety of Converting Intersections to Roundabouts: Review of Evidence from Non-U.S. Studies
Authors: Elvik Rune
Published: April 2007

A meta-analysis of studies reported outside the United States was performed to evaluate the effects on road safety of converting intersections to roundabouts. Twenty-eight studies that provided 113 estimates of effect were evaluated. State-of-the-art techniques of meta-analysis were applied to synthesize evidence from these evaluation studies. A meta-regression analysis was performed, and the possible presence of publication bias was tested and adjusted using the trim-and-fill method. The results show that roundabouts are associated with a 30% to 50% reduction in the number of injury accidents. Fatal accidents are reduced by 50% to 70%. Effects on property damage accidents are highly uncertain, but in three-leg intersections, an increase often will occur. Evidence from the evaluation studies, although highly uncertain, suggests that the effect of roundabouts on injury accidents is greater in four-leg intersections than in three-leg intersections, and it is greater in intersections previously controlled by yield signs than in intersections previously controlled by traffic signals. Few studies have evaluated in detail the effects on safety of design parameters for roundabouts. Findings are inconsistent, but the majority of studies find that small roundabouts (a small diameter of the central traffic island) are safer than large roundabouts (a large diameter of the central traffic island).
Determination of Storage Lengths of Left-Turn Lanes at Unsignalized Intersections Using M/G2/1 Queuing
Authors: Lertworawanich Ponlathep , Elefteriadou Lily
Published: April 2007

Inadequate lengths of left-turning lanes can have negative effects on the performance of unsignalized intersections. Existing methods are inadequate for recommending appropriate storage lengths as a function of the traffic demands. This study uses an M/G2/1 queuing system to develop a model for determining storage lengths of left-turning lanes for unsignalized intersections based on probability of lane overflow. Left-turning vehicle arrivals are assumed to be Poisson arrival processes. Service times of left-turning vehicles are categorized into two groups: ( a) service times incurred by the vehicles that arrive when the left-turning lane is empty, and ( b) service times incurred by the vehicles that arrive when the left-turning lane is not empty. The effects of heavy vehicles on lengths of left-turning lanes are also taken into account. Recommended storage lengths of left-turning lanes are estimated using the proposed method and are provided for various combinations of opposing volumes, left-turning volumes, and threshold probabilities of lane overflow. To select values of the threshold probability of lane overflow, many factors should be considered, such as safety, site-specific conditions, accident records, operating speeds, and economics. The results of the proposed method were compared to those provided in the 2001 AASHTO Green Book. The 2001 AASHTO Green Book overestimates the storage lengths required for left-turning lanes when opposing and left-turning volumes have fewer than 900 vehicles per hour and 500 vehicles per hour, respectively, but it underestimates storage lengths when left-turning volumes are near capacity.
Optimal Location of U-Turn Median Openings on Roadways
Authors: Zhou Huaguo , Hsu Peter , Lu Jian John , Wright John E.
Published: April 2007

Many state and local transportation agencies have considered using U-turns as alternatives to direct left turns from driveways or side streets. Median designs are used that prohibit left turns onto the facility and mid-block U-turn median openings to accommodate diverted left turns from side streets or driveways. The location of these U-turn median openings has a great impact on the operations of U-turns. Traffic operations (weaving and delay) for right turns followed by U-turn movements on urban or suburban multilane roadways were analyzed. A working model was developed to guide the location of U-turn median openings by minimizing the average delay for U-turn movements. A case study demonstrates the operational and safety benefits of optimal U-turn median opening location.
Traffic Planning Models for Single-Point and Tight Diamond Interchanges
Authors: Bared Joe G. , Powell Alvin , Kaisar Evangelos
Published: April 2007

Although the single-point interchange (SPI) has been around for approximately three decades, users do not yet have a simplified procedure to evaluate its traffic performance with a similar configuration, the tight diamond interchange (TDI). Several studies have derived general results without decisive conclusions or with partial coverage to assist the users in the selection process. Simulation modeling is used to compare operational traffic performances of isolated SPI and TDI without frontage roads. Modeling was conducted on similar geometries over a wide distribution of traffic flow conditions (101 scenarios). The 101 scenarios were run for both SPI and TDI to derive control delay, stop time, and percent stops from CORSIM. The multivariate statistical comparison of all three variables showed a combined significant difference between the two interchange types, favoring SPI. TDI created more delay, stop time, and percent stops when the left-turn off-ramp flows were very high. Regression models were derived to estimate the three measures for both SPI and TDI. The models are robust and are functions of the highest flows on the cross street and off-ramps. These models are tools that can help planners in the evaluation and selection process of these interchange configurations.
Speed Differential as a Measure to Evaluate the Need for Right-Turn Deceleration Lanes at Unsignalized Intersections
Authors: Hadi Mohammed A. , Thakkar Jan
Published: April 2007

Limited research is available to help transportation agencies make decisions about installing right-turn deceleration lanes at uncontrolled approaches of unsignalized intersections and driveways. Criteria for right-turn lanes developed by some agencies do not adequately consider the effects of through and right-turn movement volumes and speeds. To evaluate the need for right-turn lanes, the percentage of through vehicles behind right-turning vehicles in the outside (right) lane that perform evasive maneuvers because of the presence of right-turning vehicles has been used as a surrogate. This measure is difficult to use under different combinations of volumes, speeds, and other operating conditions; it also cannot be estimated from traffic simulation models if these models are used to evaluate the need for right-turn deceleration lanes. Safety is the most important factor when deciding to provide a deceleration right lane. The speed differential between through vehicles affected by right-turning vehicles and those not affected by these turns is used to determine the need for right-turn deceleration lanes at unsignalized intersections. The speed differential measure has been shown to be a surrogate to safety and to be related to crash involvement. To determine the total speed differential caused by right-turning vehicles in the outside lane, two variables are needed: the number of through vehicles in the outside lane affected by right-turning vehicles and the average drop in speed of affected vehicles. Total speed differential can be used to evaluate the need for a right-turn deceleration lane.
Romanian Model for Road Sector Restructuring
Authors: Robinson Richard , Stanciu Michael M.
Published: April 2007

During the last 20 years of the Communist regime in Romania, the road network was allowed to fall into decline. But since 1993 Romania’s plans for accession to the European Union have led to an increased emphasis on effectiveness and efficiency of the road transport system, and plans have been prepared and implemented for restructuring the road sector. Progress in the restructuring is charted in the areas of road sector financing, management, and regulatory and institutional development. Efficiencies have resulted from greater specificity of operations and increased use of competition. There have been remarkably few losses resulting from this process. The approach adopted in Romania provides a simple framework that has potential for application throughout Central and Eastern Europe, and perhaps more widely, for improving the effectiveness and efficiency of road network management arrangements.
Evaluation of Private-Sector Asset Management Practices
Authors: Pal Shaumik , Sriraj P. S. , Ogard Libby , McNeil Sue
Published: April 2007

The focus of the transportation industry, in both the public and private sectors, has slowly been changing from construction and expansion to that of preservation, as a result of various factors. Private-sector industries have made strides in asset management that could be beneficial to the public sector. Private-sector asset management principles and concepts that would form an integral part of any asset management program employed by state transportation agencies and that are transferable to the public sector, especially state departments of transportation, are identified. An overview of best practices in asset management in the private sector is presented. Thus, lessons learned are identified based on a synthesis of case studies. The analysis has been done by carefully examining asset management practices of seven near-transportation private-sector companies. Included are case studies from two railroads, two airlines, two energy companies, and one railcar leasing company. The case studies highlight the need for communication, tools, and education as well as an information technology foundation from which asset management can be practiced effectively.
Traffic Signal Operations Education Through Hands-On Experience: Lessons Learned from a Workshop Prototype
Authors: Kyte Michael , Abdel-Rahim Ahmed , Lines Melissa
Published: April 2007

The development, implementation, and assessment of the traffic signal summer workshop (TSSW) are explored. An innovative educational prototype that has been conducted at the University of Idaho during the past two summers, TSSW addresses several critical issues, including the need to educate and train university engineering students in different ways, and the lack of adequately trained engineers and technicians prepared to design and manage today’s traffic signal infrastructure. Those issues are discussed along with the pedagogical basis for hands-on experiences in engineering education. Also discussed is how the university has responded, with the TSSW prototype, to the need to deliver transportation engineering education in a new way.
Technology Transfer of Intelligent Transport Systems: China and the Netherlands
Authors: van Zuylen Henk J. , Chen Yu Sen
Published: April 2007

China is a developing country with a great need for an expansion of its transport system. Its policy aim is, among others, stimulating the role of the car in its transport system. That creates problems similar to those found in nearly all other countries in the world: congestion and inefficiency of the road transport system, especially in and around cities. To deal with those problems and to speed up the process of solving them, the Chinese cities cooperate with experts from other countries. Intelligent transport systems (ITS) are seen as a key to solving urban congestion problems. A cooperation agreement has been signed between the Chinese government, certain Chinese cities, and the Netherlands Ministry of Transport that aims to exchange experts, execute shared research and development, and provide training. The shared research shows that many of the traffic problems in Chinese cities differ very little from problems found in European cities: many of the problems concern particularly the interfaces between high-capacity urban freeways and the urban road network. The technology transfer was executed partly by providing training to Chinese experts. The training program is based on two principles: training for impact and training the trainers. The impact concerns participants applying what was learned from training to their daily practice, and their improved ability to work on solving traffic problems. Course participants are stimulated to become trainers themselves. The first results of the Chinese–Netherlands ITS training center are very promising.
Linking Economic Development to Highway Improvements: Pine Ridge Reservation, South Dakota
Authors: Khan Sakina , Levy David
Published: April 2007

Much of the literature on the economic benefits associated with investments in transportation infrastructure focuses on locations with at least some measure of private-sector economic activity. The focus here is on the Pine Ridge Indian Reservation in South Dakota, an area with extremely limited private economic activity and a transportation network with limited connectivity and accessibility. The study was one of a series sponsored by FHWA to examine linkages between transportation improvements and economic development in rural areas. The Pine Ridge study established a framework for analyzing these linkages and focused the analysis on tourism, a key sector that both offers great potential for economic development and is dependent on improvements in transportation infrastructure. The analysis estimated the potential benefits of the tourism sector and identified the transportation improvements that would be needed to support this sector. It was found that, assuming implementation of a suite of supportive initiatives, a mature tourism sector at Pine Ridge could attract more than 1 million visitors each year, which would have an estimated total economic impact of $153 million during a 15-year period. By the end of the analysis period, these tourists would generate more than 1 million automobile trips per year, with a peak average daily traffic of 5,200 vehicles. The local enhancements in transportation infrastructure that would be needed to provide adequate levels of service include both upgrading the functional class of key roads and performing adequate maintenance throughout the life cycle of the improved roads. The costs of these transportation investments are estimated at $73.3 million.
Effective Transfer of Research Results: Human Element for Successful Transfer
Authors: Elrahman O. A.
Published: April 2007

New technology is used in transportation to preserve competitiveness and maintain operational efficiency and effectiveness. Technology transfer is the medium for introducing a new technology into an organization: the missing link between research and operations and the bridge between theoretical knowledge and its practical application. Whether the product of an agency’s own research or the research of others, technology will not be successfully transferred through the mere delivery of reports. That is but one step in the transfer process, yet it is often mistakenly considered to signal completion of the process. Experience has proved that relying solely on report delivery to transfer research products is bound to yield unsuccessful transfer. That passive mode of communication, with the human element almost absent, has proved futile. The effective transfer of technology entails the dedication and commitment of specialists, time, and funds, along with report delivery. An organizational climate conducive to successful technology institutionalization in public transportation agencies was examined with emphasis on the often-overlooked human element. This focus acknowledges that an active interaction between technology provider and receiver greatly facilitates a successful transfer. Components were developed of an effective framework for technology transfer consisting of two fundamental elements: a solid foundation and an effective transfer infrastructure. A solid foundation is established when ( a) top management commits the organization to transfer efforts, ( b) human and financial resources are committed to such efforts, and ( c) the organizational culture embraces change and works to dissolve resistance to new technology introduction. An effective transfer infrastructure uses seamless communication among all parties involved, to avert problems before they arise and strengthen performance at each step.
Multicriteria Project Portfolio Selection: Case Study for Intelligent Transportation Systems
Authors: Ghaeli M. Reza , Vavrik John , Nasvadi Glenyth
Published: April 2007

Transportation strategies encompass a portfolio of projects in which choices must be made between competing alternatives. An appropriate portfolio of projects is essential for the success and growth of transportation agencies. The introduction and implementation of emerging technologies such as intelligent transportation systems (ITS) increase the need for more effective decision-making approaches and project selection in the coming years. Transportation projects, particularly, have a broad impact on the public and are multicriteria in nature. The projects also involve several elements of risk, such as project success, public acceptance, or public image. Traditional methods of project evaluation such as benefit–cost analysis focus mainly on the financial rewards of projects and do not sufficiently consider multicriteria and risk evaluations in an integrated framework. Development of an objective and systematic methodology that could address the multicriteria nature of the projects and also deal with their risks and rewards is necessary for both private and public agencies. This need is important particularly when new technologies are implemented, information on project impacts is insufficient, and resources are constrained. An integrated project portfolio selection model is introduced based on the well-established methodologies used for multicriteria evaluation and proven concepts used for portfolio selection in the finance discipline. The new methodology significantly facilitates decision making by integrating both the risk and the value of projects. A case study for selecting ITS projects in a public agency is demonstrated. Guidance is provided in nontechnical language for interpreting the outputs of the methodology.
Laboratory Evaluation of GeoGauge for Compaction Control
Authors: Lenke Lary R. , McKeen R. Gordon , Grush Matt P.
Published: April 2007

The use of nuclear methods for compaction control is increasingly problematic for state highway agencies. Regulatory and safety issues have prompted agencies such as the New Mexico State Highway and Transportation Department to look for nonnuclear alternatives for compaction control. A laboratory evaluation of one such commercially available device, known as the GeoGauge, is described. The GeoGauge measures soil stiffness, arguably a more viable engineering parameter than moisture—density measurement. The GeoGauge was found to measure soil stiffness as advertised. Results relating moisture, density, and stiffness were found to be consistent with earlier research on compaction and mechanical strength of soils. However, because of the dynamic nature of the measurement obtained with the GeoGauge and associated boundary constraints, the ability to obtain a target value for stiffness in the laboratory has proved to be elusive. Because of the promising nature of the GeoGauge technology, and because it measures a true engineering mechanical property, a paradigm shift may be necessary for its implementation in field compaction control. Future specifications for compaction using this technology may require specific controls of moisture and compaction equipment with stiffness monitoring via the GeoGauge.
Engineering Properties of Recycled Plastic Pins for Slope Stabilization
Authors: Bowders John J. , Loehr J. Erik , Salim Hani , Chen Cheng-Wei
Published: April 2007

An ongoing demonstration project has shown the feasibility of using slender (90 mm × 90 mm × 2.4 m) recycled plastic pins (RPPs) for in situ reinforcement of slopes and embankments. The technique uses RPPs driven into the face of the slope in a grid pattern to intercept the sliding surface and “pin” the slope. The engineering properties of the RPPs, including the compressive, tensile, and flexural strength along with creep behavior, dictate the design and construction practice. Constituent materials and manufacturing processes are highly variable among the more than 30 U.S. manufacturers. A specification for acceptance of the members is needed; however, before an effective specification can be developed, the appropriate engineering properties and design requirements for the RPPs must be determined. The engineering properties and driving performance of four different types of members were evaluated and are reported on. Additional evaluations are under way.
Geosynthetic-Reinforced Soil Walls
Authors: Crouse Phillip E. , Wu Jonathan T. H.
Published: April 2007

An extensive literature review was conducted to collect and synthesize information on geosynthetic-reinforced soil (GRS) walls that had been monitored for extended periods of time for assessment of their long-term performance characteristics. As a result, seven GRS retaining wall projects were selected. These projects typically had well-documented, longterm reinforcement strain data, wall deformation data, and design information. The walls range from 4.5 m to over 12 m in height and typically include surcharge loads composed of earth fills or traffic loads. Reinforcement materials were polypropylene and polyester geogrids or geotextiles, ranging in short-term strength from 5.8 kN/m to more than 17 kN/m. The facings used on the walls were concrete modular blocks, concrete panels, or wrapped geotextile surfaces. Some of the walls were constructed on poor foundations, whereas others were constructed on competent foundation materials. The environmental conditions vary from freezing temperatures in Ontario, Canada, to temperatures up to 44°C for walls built in the state of Arizona. The measured performance data for the seven GRS walls were evaluated in detail. The results indicate that creep deformation was very small when well-compacted granular backfill was employed and that current design methods are overly conservative regarding long-term creep of geosynthetic reinforcement in the GRS walls. A rational procedure for predicting long-term creep deformation of GRS walls is proposed that involves conducting a soil-geosynthetic interactive performance test with on-site soil and the use of a long-term creep equation developed on the basis of the behavior of the seven GRS walls.
Dynamic Finite Element Analysis of Vessel–Pier–Soil Interaction During Barge Impact Events
Authors: Consolazio Gary R. , Lehr G. Benjamin , McVay Michael C.
Published: April 2007

Current specifications for highway bridge design provide empirical relationships for computing lateral impact loads generated during barge collisions; however, these relationships are based on limited experimental data. To better understand and characterize such loads, dynamic finite element analysis techniques were employed to simulate vessel impact conditions never before tested experimentally. Descriptions of the methods used to model a hopper barge, bridge piers, and soil–structure interaction are given. Impact simulation results, including time histories of impact loads and barge deformations, are presented and compared with data generated using current bridge design specifications.
Load and Resistance Factor Design, Cost, and Risk: Designing a Drilled-Shaft Load Test Program in Florida Limestone
Authors: McVay Michael C. , Ellis Ralph D. , Birgisson Bjorn , Consolazio Gary R. , Putcha Sastry , Lee Sang Min
Published: April 2007

Currently there are few if any guidelines on estimating the number of load tests in the design of drilled-shaft foundations in Florida limestone. For instance, for many sites there may be a similar number of field load tests but a significantly different number of design shafts. Moreover, little if any information exists on risk or reliability versus cost of drilled-shaft foundations or on the cost of field load testing. The collection of a large database of drilled-shaft tests (more than 25 with Osterberg and Statnamic devices), in situ laboratory data, drilled-shaft construction costs, and field load testing costs for Florida limestone is reported on. From the field load tests, the average unit skin friction for various sites was found, as well as the predicted values based on the Florida Department of Transportation recommended design approach. Next, using load and resistance factor design (LRFD), the resistance (ϕ) values were found for various reliabilities (risk or probability of failure). Once the factored design loads were known (from plans), drilled-shaft lengths were estimated on the basis of the computed LRFD ϕ-values for different reliabilities (i.e., risk). From the linear length of the designed shaft as well as the expected cost per meter, a plot of total foundation cost versus reliability (risk) was generated for each site. On the basis of the latter plot, acceptable risk, and the cost of field load testing (bid and itemized), the designer can identify the cost savings of load testing and the appropriate number of tests to be performed.
Soil Arching over Deeply Buried Thermoplastic Pipe
Authors: Sargand Shad M. , Masada Teruhisa
Published: April 2007

Soil arching associated with buried thermoplastic pipe is discussed. First, the soil arching phenomenon is described. Then two different approaches are mentioned from the literature to represent the degree of soil arching (or vertical arching factor). The elastic solutions of Burns and Richard are revisited to derive expressions for the vertical soil arching factor for buried pipe. Comparison of the elastic solutions and field soil pressure cell readings reveals the importance of incorporating a bending stiffness parameter. With this finding, the AASHTO method for calculating the load on buried pipe is evaluated against the elastic solutions. The analysis reveals that the AASHTO method is conservative, overestimating the load on thermoplastic pipe by up to 30%. Further evidence to support the finding is found within the strain gauge readings taken on the pipe walls in the field. Therefore, alternative equations derived directly from the elastic solutions are recommended to predict the load on buried thermoplastic pipe instead of the AASHTO method.