bluuebunny/crossref_metadata_2025 huggingface dataset:
Recognition Distances of Different Pavement Arrow Designs During Daytime and Nighttime
Authors: Zwahlen Helmut T. , Schnell Thomas , Miescher Sarah
Published: April 2007

This study was conducted to test the visibility of five designs for pavement marking arrows at both full scale and half scale. Two designs were standard arrows (the Ohio and Federal arrows), and three were elongated arrows (Australian, Swiss, and an experimental arrow). A field study was conducted at an abandoned airport test site for both daytime and nighttime (low-beam headlight) conditions. Ten young subjects with normal vision were tested. The subjects drove a vehicle equipped with a distance-measuring instrument and were asked to indicate what direction the arrow pointed to at the earliest point when they could correctly do so. The elongated full-scale arrows provided significantly longer recognition distances than their standard full-scale counterparts. For the half-scale arrows, recognition distances did not differ as much across designs. Further analysis indicated that successive pairs of half-scale standard arrows provide longer recognition distances than a single application of the fullscale standard arrow, with the added benefits of redundant cueing. It should be noted that the substantial recognition distance gain obtained by applying successive pairs of the half-scale arrows comes with a 50 percent savings in material cost. It is also quite likely that installation of half-scale arrows is easier and quicker and that they are less prone to wear and tear because of their smaller size.
Driver Preview Distances at Night Based on Driver Eye Scanning Recordings as a Function of Pavement Marking Retroreflectivities
Authors: Schnell Thomas , Zwahlen Helmut T.
Published: April 2007

Pavement marking visibility models and tightly controlled pavement marking field experiments indicate that increased pavement marking retroreflectivity does in fact result in longer pavement marking visibility distances. The authors suggest that drivers should be provided with a pavement marking visibility distance long enough to allow for a preview time of 3.65 s at a given vehicle speed. This minimum required preview distance can be translated into a minimum required pavement marking retroreflectance. Questions were raised that perhaps drivers may not take advantage of brighter pavement markings (increased retroreflectance)—that is, drivers may not be looking as far ahead as possible from a pavement marking visibility point of view. This study was conducted to test whether drivers increase their longitudinal eye fixation distance when pavement marking retroreflectance is increased. Eye scanning data from six subjects were used to establish longitudinal eye fixation distributions on straight and level roads under low-beam illumination at night. In general, drivers appear to adjust their visual information acquisition behavior (longitudinal eye fixation distances and eye fixation preview times) when driving on roads with bright and highly visible pavement markings. Within the range of pavement marking retroreflectances investigated, it appears that, at least for half the drivers tested, brighter markings are indeed better and provide longer preview distances, which is desirable from an information acquisition, information processing, and safety point of view.
Legibility of Traffic Sign Text and Symbols
Authors: Zwahlen Helmut T. , Schnell Thomas
Published: April 2007

An exploratory daytime and nighttime sign recognition and legibility field driving experiment involving 11 new reflectorized right-shoulder-mounted traffic signs and 10 young, healthy subjects (three replications) is described here. It was hypothesized that daytime conditions would provide longer recognition and legibility distances than nighttime conditions and that signs with bold symbols would provide longer recognition and legibility distances than textual signs. Also of interest was the formulation of the instructions to the subjects, which is likely to influence the legibility and recognition distances. Whereas other researchers have encouraged subjects to guess the symbols or legends, it was emphasized in the instructions of this experiment that the subjects were to say aloud the information on the traffic signs at that point during the approach when they could clearly (with near 100 percent certainty) identify all visual details of the message or the symbol. By comparing these results with the results of other studies, it was found that legend and symbol identification under clearly seen conditions provides legibility and recognition distances that are considerably shorter than those obtained if guessing is allowed. The average daytime legibility and recognition distances were about 1.8 times longer than the average nighttime legibility and recognition distances. It may be tentatively concluded that when reporting on field legibility research, it is of utmost importance to provide the reader with detailed information about how the subjects were instructed to respond to the stimuli (e.g., guessing was allowed versus clearly seen message). From the data obtained in this study, it appears that the effect of the subject instruction formulation is stronger under nighttime low-beam conditions than during daytime.
Long-Distance Travel by Women: Results from the 1995 American Travel Survey
Authors: Mallett William J.
Published: April 2007

Research on women’s mobility has focused mostly on local travel, partly as a result of data availability. Women’s long-distance travel, defined as trips over 161 km (100 mi) one way, is examined, with data from the 1995 American Travel Survey (ATS). Conducted for the Bureau of Transportation Statistics by the Bureau of the Census, the ATS collected information on the origin, destination, volume, and characteristics of long-distance travel from 80,000 households in the United States. Data are presented on women’s long-distance travel disaggregated by, among other things, trip purpose, trip mode, age, race/ethnicity, and household type. Where possible and appropriate, ATS data are compared with data from 1977, the last time such a survey was conducted. The data show women made fewer long-distance trips than men in 1995 and the disparity between the sexes is virtually unchanged since 1977. About 80 percent of the difference in trip making results from men taking more than twice the number of business trips as women, despite women’s business travel having grown faster than men’s over the past 18 years. Most of the rest of the difference results from men’s greater trip making for outdoor recreation. Differences in long-distance travel behavior can be explained, to a degree, by women’s lower income, lower employment rates, and lower driver’s licensing rate, and because women are more likely to be the primary caregivers for children whether they work outside of the home or not.
Examining Trip-Chaining Behavior: Comparison of Travel by Men and Women
Authors: McGuckin Nancy , Murakami Elaine
Published: April 2007

Gender and household life cycle together affect daily travel behavior. Although this makes intuitive sense, transportation planners and policy makers have done little to understand what effect and impact these factors have on daily transportation choices. The 1995 Nationwide Personal Transportation Survey was used to examine trip-chaining behavior of adult men and women traveling Monday through Friday. The data show that women continue to make more trips to perform household-sustaining activities such as shopping and family errands to a greater extent than men. Women, especially with children in the household, are more likely to chain these household-sustaining trips to the trip to and from work. Women’s participation in the labor force is at an all-time high, but women’s patterns in travel to work are different from men’s patterns, and they vary with family and life-cycle status. The type and location of jobs that women take are likely affected by their greater household and family responsibilities. The biggest question for the future is whether and how the changes in women’s status in the workplace, and perhaps the concomitant change in the household dynamics and responsibilities, will affect travel behavior of both men and women. These changes will deeply affect the development of programs related to transit, land-use planning, work schedules, telecommuting, and other programs related to automobile use.
Heuristic Wayfinding for Nonmotorized Transport
Authors: Jotin Khisty C.
Published: April 2007

Heuristic processes are described for finding the shortest path by looking at maps and sketches representing transportation networks drawn true to scale and not to scale. Nine experiments were conducted and the results were compared with those derived from Moore’s algorithm. Fifty subjects in each experiment were given a fixed amount of time to find the shortest path. The majority of subjects used two mental processes to demarcate the shortest path. Two of the nine experiments required finding the safest path through a network. All experiments support the general belief that most people are able to choose the shortest or the safest path with some degree of accuracy. The results of these experiments and the interviews with the subjects indicate that good maps and sketches are important for steering people in wayfinding, particularly those using nonmotorized transportation.
Transportation Project Selection Through Robustness Analysis for Developing Countries
Authors: Khisty C.J. , Sriraj P.S.
Published: April 2007

The decision-making process within infrastructure projects in the public domain comes under severe scrutiny—from the public and the media—particularly in the initial planning stages. This process becomes progressively complicated as the degree of uncertainty embedded in the outcome of the project increases. Such complications can become more critical in developing countries, where funding and resources are scarce. One way to address this dilemma is to use robustness analysis, a comparatively new technique that has not been applied much in the past. Robustness analysis is a technique used in infrastructure planning that emphasizes the need, under condition of high uncertainty, to take early decisions in a time-phased sequence, so as to preserve many future options that currently appear attractive. The concepts of robustness analysis are outlined, and its use in public project selection is explained through two transportation-related examples. The results of this exercise indicate that robustness analysis is easy to comprehend, is relatively simple to use, and provides the flexibility needed in long-range planning to undertake decision making under uncertainty.
Rehabilitation of Tappan Zee Bridge Using Precast Concrete Composite Deck Units
Authors: White Richard N. , Smith Peter
Published: April 2007

The criteria used for successful rehabilitation of decks of major bridges when it is not feasible to close the bridge to traffic are described. These criteria are described with specific reference to recent work on the trestle spans of the Tappan Zee Bridge over the Hudson River near New York City. The results of an experimental program conducted with a full-scale, 10-m-span, lightweight concrete slab-steel beam composite bridge deck unit intended for later use in rehabilitating the through-truss decks of the bridge are also described. Loading history included 107 cycles of flexural fatigue loading followed by a flexural load capacity test. Measured values of capacity and midspan deflection at this ultimate load level are compared with simplified analytical predictions. A description of the actual rehabilitation process used on the Tappan Zee Bridge deck is also provided.
Bridge Software Validation Guidelines and Examples
Authors: Mlynarski Mark , Puckett Jay A. , Clancy Chad M. , Goodrich Brian L. , Jablin Mark C. , Smyers William , Wilson Ken
Published: April 2007

NCHRP 12-50 is a research project to investigate current software validation procedures and to provide an improved method of verifying bridge design and analysis software. The removal of errors in bridge design and analysis software has a far-reaching impact on safety assurance in the design and rating of bridges. Bridge engineers are relying on automated computations at an increasing rate. Automation of bridge computations is now an integral part of routine practice. In theory, this software should be error free—yet perfect software remains elusive. The number of bridge types and geometric configurations, materials, and loadings creates a large solution domain that must be addressed. The validation method currently being developed involves the automated generation of a series of test suites. Each test suite will contain input files for several analysis engines (software packages) and the results of the analyses and designs performed by these engines. The automatic generation of input files for a particular software package enables thousands of different cases to be created in a matter of minutes. Similarly, the output from the engines can be compared automatically using database or spreadsheet software. Each problem generated will have slightly varying input parmeters. The goal is to increment the various input parameters to test as many articles of the LRFD Specifications as possible. This novel, systematic, and automated approach provides guidelines that can be applied to a host of computational processes associated with bridge engineering, specification development, and software maintenance. Some examples are presented to illustrate the process.
Australia’s Bridge Design Load Model: Planning for an Efficient Road Transport Industry
Authors: Heywood Rob , Gordon Ross , Boully Geoff
Published: April 2007

A new Australian bridge design traffic loading standard for design and construction of Australian bridges was developed. The loading model is expected to set the bridge design standard for the next 25 years. This is an important visionary task, an investment for future improvements in transport efficiency, and an investment for our grandchildren, which was motivated by the increased transport efficiency that this generation has been able to achieve because of the investment of our grandparents. The challenge is to appropriately and effectively provide for the future in a manner that is consistent with the potential benefits and costs. The complexities of a range of traffic and vehicle loading scenarios, vehicle loading practices and enforcement, an infinite variety of bridge spans and forms of construction, and future unknown vehicle and bridge technologies are combined to develop, in collaboration with AUSTROADS and other interested bodies, a recommended bridge design load. The load model represents a substantial increase from the current design load to be one of the heaviest in the world. The load model’s features include a moving load model (M1600) that forms the basis for the application of dynamic load allowances, centrifugal and braking forces, and a stationary load model (S1600). The load model is designed to represent the traffic of the future and hence ensure the future productivity of Australia’s road transport industry. It is a bridge engineering contribution to Australia’s international competitiveness.
Practical Applications of a Bridge Management System in Japan
Authors: Miyamoto Ayaho , Kawamura Kei , Nakamura Hideaki
Published: April 2007

Recently, the necessity of developing a practical bridge management system (BMS) has been pointed out in Japan, because the maintenance of existing bridges has become a major social concern. The aim of this study was to develop a practical BMS for deteriorated concrete bridges. The proposed system (J-BMS) uses multilayered neural networks to predict deterioration processes in existing bridges, to construct an optimal maintenance plan for repair or strengthening measures based on minimizing life-cycle cost, and to estimate the maintenance cost. A comparison of the results of applying this system to some actual in-service bridges with the results of questionnaire surveys of experts indicates that optimal maintenance planning as well as bridge rating can be predicted accurately by this system.
Aesthetics of Cable-Stayed Bridges
Authors: Tang Man-Chung
Published: April 2007

Among the various bridge types, cable-stayed bridges offer the most intriguing configurations. By varying the shape of the towers, the arrangement of the cables, and the cross section of the deck girder, it is almost always possible to create a cable-stayed bridge to fit in any given land-scape. Since their debut 45 years ago, the beauty of cable-stayed bridges has piqued the interest of engineers and nonengineers alike.
Performance of Precast Segmental Structures with External Tendons Under Moderate Seismic Conditions
Authors: Moreton Alan J. , Wolek Arthur L. , Hoffman Garrett G. , Goñi Juan J. , Rodriguez José M.
Published: April 2007

The 1998 draft of the AASHTO Guide Specifications for Segmental Bridges restricts the use of external posttensioning tendons in regions of severe seismic activity, Seismic Performance Category (SPC) C and SPC D, by requiring that at least 50 percent of the tendons be internal to the concrete. This requirement has also been applied to selected projects in SPC B designed before or during the development of the 1998 draft. A case study is presented that substantiates the use of purely externally posttensioned structures in SPC B and indicates that the requirement may not even be necessary for SPCs C and D. The case study concerns a project in which precast segmental superstructures carry a light-rail access system to the John F. Kennedy International Airport in New York. Two different precast segmental superstructures with external tendons are modeled using a multimode spectral analysis. The goal is to determine the stress levels under the worst possible seismic conditions for SPC B and, in particular, to establish whether the joints would open or crack and the external tendons would suffer any distress. For both models, results show conclusively that the forces, moments, and stresses in the superstructure are less severe than under normal service level loads. Thus, there is no risk of cracking or opening of joints, and the external tendons experience no increase in stress over their normal service conditions. In addition, research shows that there is no significant difference in behavior between external and internal tendons for loads within ultimate conditions.
Risk-Based Design of Bridge Scour Countermeasures
Authors: Pearson David R. , Jones J. Sterling , Stein Stuart M.
Published: April 2007

HYRISK was originally developed to prioritize bridges with unknown foundations to determine where to spend limited resources to investigate those bridges. It was later modified to prioritize bridges of any type for scour evaluations where there are limited resources for the evaluations each year. The model is based on information that can be read from the National Bridge Inventory and accounts for average daily traffic, detour lengths, value of lost time, risks associated with scour at various types of foundations, bridge condition, bridge geometry, and bridge age. The model can readily be modified for use as a decision tool to select various levels of countermeasures for a bridge that has already been evaluate and determined to be scour critical for some probability flood event. For that application, the model can use the determined probability of failure and does not need to rely on the assumed risks for various foundation types. The model will need to account for the risk of loss of life on the basis of recent experience. The bridge owner will provide information on the expected life of the bridge and the costs of various levels of protection. The model will determine the optimum level of protection for the bridge and the maximum expenditures that should be accepted to increase the level of protection.
Integrated Multimedia Uniform Bridge Element Identification System Database for Bridge Inspection and Maintenance
Authors: Haque Mohammed , Pongponrat Kajpong
Published: April 2007

Bridge inspection information management poses a conundrum to transportation agencies across the nation. Today, there is a real need to use all media types, including text, image, sound, and video, to document bridge inspection projects, rather than only text. The development of an interactive, menu-driven, PC-based bridge inspection and maintenance database system using various information technologies to provide multimedia documentation is addressed. The system is geared to identify each bridge element uniquely using the Uniform Bridge Element Identification System (UBEIS). UBEIS is a generalized multidimensional coordinate system consisting of a string of alphanumeric characters that does not require any structural detail drawings, such as framing plan or cross sections, to identify a unique structural element. This database system enables bridge engineers to evaluate future rehabilitation needs, track the condition of structurally deficient members, and keep the rehabilitation and replacement history of the bridge. The system can be considered as a practical link between inspection and rehabilitation and acts as a warning system against bridge deterioration and potential failure.
Ultrasonic Inspection of Bridge Hanger Pins
Authors: Graybeal B. A. , Walther R. A. , Washer G. A.
Published: April 2007

Ultrasonic inspection is currently one of the most common and reliable methods used in the inspection of hanger pins in pin-and-hanger bridge structures. Recently, a pin-and-hanger connection on a heavily traveled truck route in the Midwest showed visual indications of being deficient. Field contact ultrasonic inspections were performed on the remaining pin connections. The field inspections indicated that a number of the pins contained cracks or significant wear grooves at the pin shear planes, or both. These pins were replaced and sent to the FHWA’s Nondestructive Evaluation Validation Center for further testing in an ultrasonic immersion tank. The results of the contact and immersion tank ultrasonic studies were nearly identical. Both methods found two pins that contained transverse cracks at the level of a shear plane, with one of these cracks encompassing a majority of the pin cross section. Clearly, for the conditions found in the study, field contact ultrasonics can accurately locate defects in hanger pins.
High-Performance Concrete in the Richlands Bridge in Virginia
Authors: Ozyildirim Celik , Gomez José P.
Published: April 2007

The Virginia Department of Transportation built a high-performance concrete (HPC) bridge in Richlands, Virginia. The beams had a minimum compressive strength of 69 MPa (10,000 psi) at 28 days; the large strands, 15 mm (0.6 in.) in diameter, were placed 51 mm (2 in.) apart. The deck concrete was designed to have a minimum compressive strength of 35 MPa (5,000 psi) and low permeability. A test program was initiated before construction to develop the HPC mixes. The development of the mixes and the construction and condition assessment of the bridge after two winters is described. The test program, field application, and inservice performance indicated that HPC concrete with high strength and low permeability can be produced using locally available material.
Optimization of Amount and Blending of Cementitious Materials in High-Performance Concrete
Authors: Bajorski Peter , Streeter Donald A.
Published: April 2007

In recent years, there has been a demand by the traveling public for longer-lasting, more durable transportation structures. One of the biggest problems encountered is the corrosion of reinforcing steel used in concrete applications. To reduce the damage caused by the ingress of chlorides, and the subsequent corrosion, the New York State Department of Transportation (NYSDOT) has developed and used a high-performance concrete, designated Class HP. As part of a continuous improvement effort to produce longer-lasting structures, research has been ongoing to further improve the characteristics of Class HP concrete. The study is a continuation of the previous experimental work performed by the NYSDOT and reported in Transportation Research Record 1574. During that study, the effects of microsilica, fly ash, and the total cementitious mass in a mixture on cracking and permeability of the resulting concrete were studied. The experimental design used in the investigation resulted in testing a minimal number of concrete mixtures yet allowed the analysis of a broad range of possible combinations. Statistical analysis of experimental data is presented, and examples of a scientific approach to experimentation are shown. The Response Surface Methodology was used with the appropriate statistical experimental designs, including the Box–Behnken design. In addition to the traditional linear regression models, a modern technique of the local regression was used.
Detecting the Extent of Corrosion with Acoustic Emission
Authors: Yoon Dong-Jin , Weiss W. Jason , Shah Surendra P.
Published: April 2007

Reinforced concrete beams were tested in flexure, and their acoustic emission (AE) response was recorded. This research was performed to investigate the characteristic AE response that is associated with microcrack development, localized crack propagation, corrosion, and debonding of the reinforcing steel in an attempt to use AE to characterize the source of damage. Concrete beams were prepared to isolate these damage mechanisms by using unreinforced, notched-unreinforced, reinforced, and corroded-reinforced specimens. The AE response was analyzed to obtain key parameters such as the total number and rate of AE events, the amplitude and duration of the events, and the characteristic features of the waveform. Initial analysis of the AE signal has shown that a difference in the AE response can be observed depending on the source of the damage. By plotting the AE signal amplitude versus duration (cross-plot), it can be seen that distributed microcracking is typically characterized by a relatively low amplitude and short duration, whereas debonding cracks have a higher amplitude and longer duration. The Felicity ratio (ratio of the load level at which AE activity begins to occur and the previous loading level) exhibits a favorable correlation with the overall damage level, and the total number of AE events that occur during unloading may provide an effective criterion for estimating the level of corrosion distress in reinforced concrete structures. Based on these results, AE parameter analysis may provide a promising approach for estimating the level of damage and corrosion distress in reinforced concrete structures.
Developing a Quantitative Rating System for Continuously Reinforced Concrete Pavement
Authors: Wu Shie-Shin
Published: April 2007

A jointed concrete pavement rating system based on sampling and quantitative surface distress data was developed several years ago for North Carolina. This rating system has been adopted by the pavement management system for the priority ranking of projects. The first attempt to develop a similar rating system for continuously reinforced concrete (CRC) pavement was made with no fruitful results. There remains an urgent need for a comparable CRC rating system for project ranking. Another attempt that used a different approach was made. A linear regression equation was developed, and the correlation with experts’ rating was reasonably good.
Planning and Implementation of a Management System for Utility Cuts
Authors: Arudi Rajagopal , Pickering Brian , Flading Joseph
Published: April 2007

Utility cuts are made in city street pavements either to install new facilities or to maintain existing ones. Controlling the quality of pavement restoration is a challenge because of the large number of cuts made annually. Although utility companies restore the pavement sections after the cuts according to available guidelines, it is often observed that the pavement within and adjacent to the cuts fails prematurely. The resulting condition has a direct influence on pavement integrity and life, maintenance cost, aesthetic value, and safety of motorists. Because existing pavement management systems do not consider the effect of utility cuts on pavement performance, municipalities such as the city of Cincinnati are currently seeking specific guidelines in the form of a utility cut management system (UCMS). The results of a study on the development of a UCMS are reported in this paper. The UCMS is a synthesis of field evaluation procedures and cost management and policy issues related to street pavement sections affected by utility cuts. The goals of the UCMS are to ( a) identify the factors most useful for evaluating performance of utility cuts; ( b) differentiate between the quality of restoration by different utilities or subcontractors; ( c) address issues related to planning, investments, and maintenance activities; and ( d) be compatible with existing pavement management systems.
Defining the Operator Interface of a Snowplow Lane Tracking System from Field Interviews and Surveys
Authors: McGehee Daniel V. , Raby Mireille , Nourse Gary E.
Published: April 2007

Maintaining lane position during low-visibility conditions can be a challenge for snowplow operators. Providing continuous and accurate lane position information to complement existing roadway cues may be the solution to increasing driver awareness. The first phase of a systemsbased approach to designing the operator interface for a snowplow lane tracking system is described. Through a systems-based approach, not only can the type of controls and displays to use for the operator interface be better defined, but the interface’s role and the amount, type, and presentation of information can be determined. In this first phase, ridealong interviews and an operator survey were used to identify factors affecting forward visibility and lane position in snowplow operations. More than 1,000 department of transportation snowplow operators from Iowa and Minnesota completed the survey. Ride-along drives showed that operators frequently lose sight of the forward roadway for brief periods and use several cues to adjust the lane position of their vehicles. Survey findings indicated that center and shoulder lines are helpful and intuitive cues for left- and right-wing plow operations. Additional findings suggest that operators need a flexible system that enables them to adjust alarm thresholds and that the operator interface should be designed as an aid rather than as a primary display. Because drivers do not have the visual resources for a dedicated display, a peripheral visual or haptic (tactile) display could be used to complement existing roadway cues.
Investigation of Passenger Vehicle Rental Rates: Case Study in Virginia
Authors: Hanson Robert A. , Kyte Cherie A.
Published: April 2007

The rental rates for centralized fleet passenger vehicles that the Virginia Department of Transportation’s (VDOT) Division of Fleet Management charges state agencies were investigated. Similar studies by Virginia’s Joint Legislative and Audit Review Commission were reviewed, Fleet Management data were analyzed, and regression analyses were performed to develop new replacement criteria and more equitable rental rates for customers. The impacts of these suggested rates on the VDOT Fleet Management budget and customers were identified.
Operating Speed on Crest Vertical Curves with Limited Stopping Sight Distance
Authors: Fambro Daniel B. , Fitzpatrick Kay , Russell Charles W.
Published: April 2007

Horizontal and vertical elements of a highway are designed based on an assumed design speed. This concept was developed in the 1930s as a mechanism for designing rural alignments to permit most drivers to operate uniformly at their desired speed. In 1938, AASHO recognized that drivers select a speed influenced by the roadway environment instead of an assumed design speed. Recent research suggests that design speed is no longer the speed adopted by the faster group of drivers but that it has become a value used to establish the sharpness of horizontal and vertical design elements. The objective of this study was to establish the relationship between design and operating speeds for crest vertical curves with limited sight distance. Geometric data and 3,500 paired speeds (speeds at control and crest sections) were collected at 36 sites in 3 states. The results indicated that both the 85th percentile and the mean operating speeds were well above the inferred design speeds of the crest vertical curves for the range of conditions studied and that the lower the design speed the larger the difference between the 85th percentile speed and the design speed. The mean reductions in speed between the control and crest sections tend to increase as available sight distance is decreased; however, the reduction in speed is less than that suggested by current AASHTO criteria.
Speed-Profile Model for a Design-Consistency Evaluation Procedure in the United States
Authors: Ottesen Jeffery L. , Krammes Raymond A.
Published: April 2007

A speed-profile model for estimating 85th percentile speeds along horizontal alignments of rural two-lane highways in the United States is documented. The model is an evaluation tool to check for speed consistency violations on alignments with design speeds less than 100 km/h (62.1 mph). The model was calibrated by using speed and geometry data collected for 138 horizontal curves and 78 approach tangents on 29 rural highways in 5 states. A preliminary evaluation suggests that the model provides reasonable estimates of the reductions in 85th percentile speeds from an approach tangent to a horizontal curve.
Experience Predicting Construction-Site Noise
Authors: Staiano Michael A.
Published: April 2007

The practical aspects of predicting construction-site noise are examined: the implementation of the prediction process, including the use of suitable source-noise emission measurement standards, the identification of propagation factors, and the assumption of meteorological conditions. The application of a prediction procedure is compared with field measurements to verify accuracy and to establish appropriate design safety margins. To estimate the site sound levels from one or more noise sources, sound attenuation was considered due to four mechanisms—spreading, atmospheric absorption, ground reflections (“ground interaction”), and barrier shielding. Noise-source emissions were measured essentially at maximum noise-generation conditions for the equipment, based on the test procedures of both the Society of Automotive Engineers and the American National Standards Institute. Prediction accuracy was verified for eight sites with 19 total locations and conditions. When observed primary-machine sound levels were compared with the predictions, the mean error was 3 dB(A). For group equipment operations and measurement-period sound levels, which are subject to source operating condition variation and mobile-equipment movement, the mean equivalent sound-level overprediction was approximately 6 dB(A).
New Paradigm for State Department of Transportation Environmental Initiatives: New York State’s Guidelines and Procedures
Authors: McVoy Gary , Sengenberger Mark , Novak Elizabeth
Published: April 2007

Public-works agencies have an obligation to enhance the environment as opportunities arise. The New York State Department of Transportation (NYSDOT) has developed an environmental initiative to make an affirmative contribution to the environment, using the department’s organizational strengths. The environmental initiative is a paradigm shift applicable to all departments of transportation (DOTs). Conventional reactive regulatory compliance can reduce unnecessary environmental damage and sometimes gain grudging regulatory agency cooperation; however, it is not a positive, satisfying way of doing the people’s work. Through proactive steps, NYSDOT has become an important part of the state’s environmental solution (often at little or no additional cost) and has changed its working relationships with environmental agencies and groups. As these agencies and groups have become partners, instead of adversaries, permit-approval times have improved, mitigation costs have declined, morale has improved, and cost-effective environmental benefits are being realized. Procedures are outlined to apply the engineering capabilities of a DOT to the environmental-stewardship responsibilities shared by all governmental organizations.
Use of Path Objects for Air Traffic Control
Authors: Barrer John N.
Published: April 2007

A path object is a set of instructions plus the values of associated parameters that would be used by an aircraft’s flight management system (FMS) or area navigation (RNAV) computer to construct a flight trajectory on the basis of the values of the parameters provided by the pilot or air traffic control (ATC) system. The concept of path objects and its applicability for development of FMS- or RNAV-based flight paths for aircraft routes are described. The use of path objects requires only a small number of parameters for specification of an RNAV route, and the computer then calculates the resulting flight path. Because most RNAV routes are just variations of the same basic shapes, many RNAV routes can be generated from a single path object by changing just one or two parameters. This offers the capability to reduce the size of the navigation database by a significant amount. This also allows the dynamic alteration of three-dimensional FMS-RNAV routes instead of radar vectoring, which represents a significant improvement in ATC procedures. Because of the compact expressions for the path objects, these procedures could be used in a voice communications environment as well as a data link environment. A path object can be thought of as a high-level language with which aircraft and ATC systems communicate flight path intentions. The concept of FMS- or RNAV-stored path objects is a change in thinking about the role of avionics technology. It offers a means of including the precision of the FMS-RNAV technology in the ATC system during the transition from today’s system to the future’s fully automated control system. This is an enabling technology that improves the ability to use and maintain FMS-RNAV in its role as a vital component of the ATC system. It has the potential to enhance future air traffic management-communication navigation surveillance concepts and applications.
Aviation System Performance Measures for State Transportation Planning
Authors: Gosling Geoffrey D.
Published: April 2007

A proposed set of aviation system performance measures that have been defined to support multimodal transportation planning in California is presented. As part of the 1998 update of the California Transportation Plan (CTP), the California Department of Transportation has defined a framework of system performance measures that could be applied on a multimodal basis to assess the performance of the transportation system, support informed decision making, and establish a coordinated and consistent process for performance measurement throughout the state. The research that is described examined approaches to measuring the performance of the aviation system that have been adopted at a national level and in other states, as well as general principles for measurement of transportation system performance that emerged from a conference held in 1997 as part of the CTP update process. The range of considerations that arise in measuring the performance of the aviation system is discussed, and potential performance measures that have been proposed to address the requirements of the CTP framework are identified. Finally, issues that will need to be addressed in implementing any comprehensive set of performance measures for the aviation component of the transportation system are discussed.
Assessing the Impact of Aviation System Performance by Using Airline Cost Functions
Authors: Hansen Mark , Gillen David , Djafarian-Tehrani Reza
Published: April 2007

The manner in which changes in the performance of the U.S. National Airspace System (NAS) affect carrier costs is examined. The methodology includes estimation of airline cost functions that contain NAS performance metrics as arguments, using quarterly data for 10 U.S. domestic airlines. The primary interest is in the impact of delay on cost performance, and performance metrics that vary by airline and quarter are developed. The potentially large number of metrics are reduced by applying factor analysis to seven underlying variables, including average delay, delay variance, and the proportion of flights that are cancelled. The analysis reveals that variations in the seven variables can be adequately captured by three or fewer factors. The three factors used correspond to “delay,” “variability,” and “disruption,” the last two of which are merged into a single “irregularity” factor in the two-factor model. When used as arguments in an airline cost function, the “disruption” factor is found to be a significant contributor to airline costs in the three-factor model, as is the “irregularity” factor in the two-factor model. No significant effect is found for the delay factor in the multifactor models. These results challenge the prevailing assumption that delay reduction is the most important benefit from investments in NAS capital and operations rules. The carrier cost savings that would result from improved NAS performance levels are estimated, and these are compared with previously published estimates.
Traditional Airport Performance Indicators: A Critical Perspective
Authors: Humphreys Ian , Francis Graham
Published: April 2007

Airport managers require effective performance measures to enable them to plan and manage within the context of rapid passenger growth and the trend toward an expansion of commercial activities. Airport performance measurement in various ownership patterns from Europe and the United States is reviewed, bringing together a rich picture of different practices. The need to be aware of contingent circumstances to evaluate airport performance objectively is emphasized. Many measures currently in use are output variables and are usually quantitative and based on what is easy to measure instead of what is important to measure. The problems of discrepancies in the definition of key variables and of attempts to achieve direct comparability between airports are examined. Consideration is given to the dysfunctional effects of measurement systems and how they can be adapted to encourage innovation and organizational learning through such techniques as best-practice benchmarking. Airport planners, managers, and academics who have an interest in performance measurement and who wish to question the role of traditional measures will be interested in the discussion. Lessons from European experience in a postprivatization environment are considered. The research recommends the adoption of a performance measurement system for airports that examines processes as well as results and that considers antecedent variables as well as outcome variables. The conclusions indicate how airport planners and managers can gain new insight into the underlying processes behind quantitative indicators and how an understanding of these processes can stimulate organizational learning and innovation.
Premium Public Parking Services: A Way to Improve Parking Operations at Airports
Authors: Fantoni Anna , Mansel Douglas M. , Mandle Peter B.
Published: April 2007

Premium public parking services, such as valet, reserved, and business parking, are becoming increasingly popular at U.S. airports. They offer an enhanced level of customer service; are important business opportunities and sources of revenue for airports; contribute to reduction of curbside congestion, thereby encouraging travelers to park instead of being dropped off or picked up; and improve an airport’s ability to compete with privately operated, off-airport parking facilities. A study was conducted at more than 14 U.S. airports and demonstrated that successful premium public parking services provide a good combination of location, parking capacity, rate structure, quality of service, and business arrangements. Although these factors are very specific to each airport, general guidelines for parking managers who wish to optimize existing parking facilities, maximize net parking revenues, and provide a high level of customer service are outlined.
Effects of Innovative Pedestrian Signs at Unsignalized Locations: Three Treatments
Authors: Huang Herman , Zegeer Charles , Nassi Richard
Published: April 2007

Three types of devices that have been used in conjunction with marked crosswalks in an attempt to improve pedestrian safety were evaluated: an overhead crosswalk sign in Seattle, Washington; pedestrian safety cones (which read, “State Law: Yield to Pedestrians in Crosswalk in Your Half of Road”) in New York State and in Portland, Oregon; and pedestrian-activated overhead signs (which read, “Stop for Pedestrians in Crosswalk”) in Tucson, Arizona. The signs were used under varying traffic and roadway conditions. The effects of these three treatments on pedestrian and motorist behavior were evaluated. The variables of interest were whether pedestrians had the benefit of motorists yielding to them; whether pedestrians had to run, hesitate, or abort their crossing; and whether pedestrians crossed in the crosswalk. The New York cones and Seattle signs were effective in increasing the numbers of pedestrians who had the benefit of motorists yielding to them. At one location in Tucson, the overhead sign increased motorist yielding to pedestrians. The signs in Seattle and Tucson were effective in reducing the number of persons who had to run, hesitate, or abort their crossing. None of the treatments had a clear effect on whether people crossed in the crosswalk. By themselves, these devices cannot ensure that motorists will slow down and yield to pedestrians. It is essential to use these and other devices along with education and enforcement, but creation of friendlier pedestrian environments (e.g., by means of implementing geometric improvements) for the purpose of reducing vehicle speeds may be more important.
Cycling and Urban Traffic Management and Control Systems
Authors: Clark Stephen D. , Page Matthew W.
Published: April 2007

Since the 1950s, cycling has been a declining mode of travel in the United Kingdom. During this same period, sophisticated techniques for managing traffic in the urban environment have been developed. Given these circumstances, the presence of cyclists is often ignored by urban traffic control (UTC) systems, which are dominated by consideration of the flows and journey times of private motorized vehicles. Authorities are enthusiastic about the promotion of cycling as a mode of travel and are looking to see if this can be assisted by use of traffic management systems. The fact that cyclists and potential cyclists vary considerably in their abilities and performance, as well as in their attitudes to timesaving and safety, is highlighted. The context of the problem is set, the specific issue of detection of cycles is examined, the potential for implementation of priority measures in different types of UTC systems is discussed, and the issue is illustrated with some actual installations. Limited European evidence would suggest that only minimum effort is needed to take explicit account of cycling when a UTC system is being implemented. This supports the idea that cyclists can be given a higher degree of consideration within a UTC system without incurring significant additional costs. Only when cycling achieves a near-dominant proportion of the trips within a city and is growing in volume, as is the case in China, is explicit consideration to cyclists given.