United States Department of Transportation

A management construct cannot be used effectively by practitioners and researchers if a common agreement on its definition is lacking. Such is the case with the term “supply chain management”—so many definitions are used that there is little consensus on what it means. Thus, the purpose of this paper is to examine the existing research in an effort to understand the concept of “supply chain management.” Various definitions of SCM and “supply chain” are reviewed, categorized, and synthesized. Definitions of supporting constructs of SCM and a framework are then offered to establish a consistent means to conceptualize SCM. Antecedents and consequences of SCM are identified, and the boundaries of SCM in terms of business functions and organizations are proposed. A conceptual model and unified definition of SCM are then presented that indicate the nature, antecedents, and consequences of the phenomena.

This report describes the annual total cost of metallic corrosion in the United States and preventive strategies for optimum corrosion management. In 1998, an amendment for a Cost of Corrosion study was included in the Transportation Equity Act for the 21st Century (TEA-21) and was approved by Congress. In the period from 1999 to 2001, CC Technologies conducted the research in a cooperative agreement with the Department of Transportation Federal Highway Administration (FHWA) and NACE International (The Corrosion Society). The total direct cost of corrosion is estimated at $276 billion per year, which is 3.1% of the 1998 U.S. gross domestic product (GDP). This cost was determined by analyzing 26 industrial sectors in which corrosion is known to exist and extrapolating the results for a nationwide estimate. The sectors were divided among five major categories: infrastructure, utilities, transportation, production and manufacturing, and government. The indirect cost of corrosion is conservatively estimated to be equal to the direct cost (i.e., total direct cost plus indirect cost is 6% of the GDP). Evidence of the large indirect corrosion costs is lost time, and thus lost productivity because of outages, delays, failures, and litigation. It was found that the sectors of drinking water and sewer systems ($36 billion), motor vehicles ($23.4 billion), and defense ($20 billion) have the largest direct corrosion impact. Within the total cost of corrosion, a total of $121 billion per year is spent on corrosion control methods and services. The current study showed that technological changes have provided many new ways to prevent corrosion and there has been improved use of available corrosion management techniques. However, better corrosion management can be achieved using preventive strategies in non-technical and technical areas. These preventive strategies include: (1) increase awareness of large corrosion costs and potential savings, (2) change the misconception that nothing can be done about corrosion, (3) change policies, regulations, standards, and management practices to increase corrosion cost-savings through sound corrosion management, (4) improve education and training of staff in recognition of corrosion control, (5) advance design practices for better corrosion management, (6) advance life prediction and performance assessment methods, and (7) advance corrosion technology through research, development, and implementation.

The authors report the results of three experiments that address the effects of health claims and nutrition information placed on restaurant menus and packaged food labels. The results indicate that when favorable nutrition information or health claims are presented, consumers have more favorable attitudes toward the product, nutrition attitudes, and purchase intentions, and they perceive risks of heart disease and stroke to be lower. The nutritional context in which a restaurant menu item is presented moderates the effects of both nutrition information and a health claim on consumer evaluations, which suggests that alternative (i.e., nontarget) menu items serve as a frame of reference against which the target menu item is evaluated.

Accurate short-term traffic flow forecasting facilitates active traffic control and trip planning. Most existing traffic flow models fail to make full use of the temporal and spatial features of traffic data. This study proposes a short-term traffic flow prediction model based on a convolution neural network (CNN) deep learning framework. In the proposed framework, the optimal input data time lags and amounts of spatial data are determined by a spatio-temporal feature selection algorithm (STFSA), and selected spatio-temporal traffic flow features are extracted from actual data and converted into a two-dimensional matrix. The CNN then learns these features to construct a predictive model. The effectiveness of the proposed method is evaluated by comparing the forecast results with actual traffic data. Other existing models are also evaluated for comparison. The proposed method outperforms baseline models in terms of accuracy.

This report serves as a comprehensive guide to traffic signal timing and documents the tasks completed in association with its development. The focus of this document is on traffic signal control principles, practices, and procedures. It describes the relationship between traffic signal timing and transportation policy and addresses maintenance and operations of traffic signals. It represents a synthesis of traffic signal timing concepts and their application and focuses on the use of detection, related timing parameters, and resulting effects to users at the intersection. It discusses advanced topics briefly to raise awareness related to their use and application.\n

The U. S. Department of Transportation was established to bring together in one place the government's major promotional and safety responsibilities in transportation. It provides the focal point for developing a system suited to the accomplishment of our transportation objectives while at the same time recognizing the necessary relationship of transportation to other social and economic objectives. The act (Public Law 89-670) creating the Department specifies as its declaration of purpose: "The Congress therefore finds that the establishment of a Department of Transportation is necessary in the public interest and to assure the coordinated, effective administration of the transportation programs of the Federal Government; to facilitate the development and improvement of coordinated transportation service, to be provided by private enterprise to the maximum extent feasible; to encourage cooperation of Federal, State, and local governments, carriers, labor, and other interested parties toward the achievement of national transportation objectives; to stimulate technological advances in transportation; to provide general leadership in the identification and solution of transportation problems; and to develop and recommend to the President and the Congress for approval national transportation policies and programs to accomplish these objectives with full and appropriate consideration of the needs of the public, users, carriers, industry, labor, and the national defense." In essence, then, the major functions of the Department are plannings, finding technical and economic solutions to all transportation policy problems, and assuring the safety of all transportation.

Auto ownership and mileage per car are shown to vary in a systematic and predictable fashion in response to neighborhood urban design and socio-economic characteristics in the Chicago, Los Angeles, and San Francisco regions. In all three cases, average auto ownership is primarily a function of the neighborhood's residential density, average per capita income, average family size and the availability of public transit. Similarly, the average annual distance driven per car is a strong function of density, income, household size and public transit, and a weaker function of the pedestrian and bicycle friendliness of the community. The similarity of these relationships among the three metro areas, despite their differences in geography and age, suggests that similar relationships may be consistent throughout the United States or worldwide. The application of the results to other metro areas is discussed. The dependence of driving on the policy-related variables of residential density, transit access, and pedestrian and bicycle-friendliness may provide policy makers with additional tools for reducing the costs and environmental impacts of transportation.

In a between-subjects experiment, the authors examine how differences in Nutrition Facts information on fat and fiber, coupled with differing claims for these nutrients (including multiple nutrient claims and a health claim), influence consumers’ product evaluations, perceptions and awareness of disease risk, and trust of the claims and Nutrition Facts information. Results show that the Nutrition Facts information regarding fat affects consumers’ evaluations and perceptions of disease risk but that information on fiber does not. Claims do not affect product evaluations or purchase intentions, and there is a weak effect of inclusion of a health claim on disease risk perceptions. Consumers are less likely to recognize incongruencies in claim and Nutrition Facts information about fiber than fat. Incongruencies regarding the level of fat in the product result in lower trust in the claim information but do not affect trust in the Nutrition Facts data. The authors discuss implications for consumer welfare and public policy.

Market share can influence perceived quality through several different mechanisms, including signaling, creating network externalities, and inclusion as an attribute in consumers’ quality functions. The direction of this potential effect is ambiguous. Making use of data on 85 different brands across 28 product categories, the authors explore the effect market share has on consumers’ perceptions of quality and the extent to which category-wide and brand-specific factors moderate this effect.

Abstract This paper examines different algorithms for calculating the shortest path from one node to all other nodes in a network. More specifically, we seek to advance the state‐of‐the‐art of computer implementation technology for such algorithms and the problems they solve by exmining the effect of innovative computer science list structures and labeling techniques on algorithmic performance. The study shows that the procedures examined indeed exert a powerful influence on solution efficiency, with the identity of the best dependent upon the topology of the network and the range of the arc distance coefficients. The study further discloses, for the problems tested, that the lable‐setting shortest path algorithm previously documented as the most efficient is dominated for all problem structures examined by the new methods.

In a laboratory experiment using a between-subjects design, the authors examine the effects on nutrition and product evaluations of nutrition claims made (e.g., “99% fat free; ” “low in calories ”) on a product package, product nutrition value levels, and enduring motivation to process nutrition information. Enduring motivation is shown to moderate the effects of product nutrition value on consumer evaluations. Also, nutrition claims interact with product nutrition value in affecting consumer perceptions of manufacturer credibility. Given the availability of nutrient levels in the Nutrition Facts panel on the back of the mock package, nutrition claims on the front of the package generally did not affect positively consumers’ overall product and purchase intention evaluations. The authors discuss some implications of these findings, suggestions for further research, and study limitations. 1 1. The generalizability of the findings from this laboratory study may be restricted because the mock package used as the stimulus was examined outside of an actual in-store purchase environment. Because consumers in store settings may spend less time and care examining Nutrition Facts panels and are subject to a variety of other influences (Cole and Balasubramanian 1992), findings from this study may not generalize to such settings.

Abstract New vapor pressure data is presented for RDX, PETN, TNT, nitroglycerin, and ammonium nitrate. By comparison with the data of previous workers, it has been possible to calculate global vapor pressure expressions which are valid over a wide range of temperatures.

The question of whether population density affects the amount of household automobile travel in the United States is revisited. Controls for income and demographics are included in a multivariate regression model of vehicle travel that includes vehicle ownership as an intermediate factor and that treats a household's pick of neighborhood density and the amount of travel as a simultaneous relationship. The data come from the 1990 Nationwide Personal Transportation Survey. It is found that density matters, but not much. A 10 percent increase in density leads to only a 0.7 percent reduction in household automobile travel. By comparison, a 10 percent increase in household income leads to a 3 percent increase in automobile travel. The results are similar when vehicle trips are used as the dependent variable. The effect of density is so small that even a relatively large-scale shift to urban densities would have a negligible impact on total vehicle travel.

Design consistency refers to the conformance of a highway's geometry to driver expectancy. Drivers make fewer errors in the vicinity of geometric features that conform to their expectations. A technique to evaluate the consistency of a design is to evaluate changes in operating speeds along an alignment. To use operating speed as a consistency tool requires the ability to accurately predict speeds as a function of the roadway geometry. In this research project, several efforts were undertaken to predict operating speed for different conditions such as on horizontal, vertical, and combined curves; on tangent sections using alignment indices; on grades using TWOPAS model; and prior to or after a horizontal curve. The findings from the different efforts were incorporated into a speed-profile model. The model can be used to evaluate the design consistency of the roadway or can be used to develop a speed profile for an alignment. The model considers both horizontal and vertical curvature and the acceleration or deceleration behavior as a vehicle moves from one feature to another.

A growing number of epidemiological studies conducted worldwide suggest an increase in the occurrence of adverse health effects in populations living, working, or going to school near major roadways. A study was designed to assess traffic emissions impacts on air quality and particle toxicity near a heavily traveled highway. In an attempt to describe the complex mixture of pollutants and atmospheric transport mechanisms affecting pollutant dispersion in this near-highway environment, several real-time and time-integrated sampling devices measured air quality concentrations at multiple distances and heights from the road. Pollutants analyzed included U.S. Environmental Protection Agency (EPA)-regulated gases, particulate matter (coarse, fine, and ultrafine), and air toxics. Pollutant measurements were synchronized with real-time traffic and meteorological monitoring devices to provide continuous and integrated assessments of the variation of near-road air pollutant concentrations and particle toxicity with changing traffic and environmental conditions, as well as distance from the road. Measurement results demonstrated the temporal and spatial impact of traffic emissions on near-road air quality. The distribution of mobile source emitted gas and particulate pollutants under all wind and traffic conditions indicated a higher proportion of elevated concentrations near the road, suggesting elevated exposures for populations spending significant amounts of time in this microenvironment. Diurnal variations in pollutant concentrations also demonstrated the impact of traffic activity and meteorology on near-road air quality. Time-resolved measurements of multiple pollutants demonstrated that traffic emissions produced a complex mixture of criteria and air toxic pollutants in this microenvironment. These results provide a foundation for future assessments of these data to identify the relationship of traffic activity and meteorology on air quality concentrations and population exposures.

Consumption of renewable energy in the United States is the highest in history, contributing to energy security, greenhouse gas reductions, and other social, economic, and environmental benefits. The largest single source of renewable energy is biomass, representing 3.9 quadrillion of 9.6 quadrillion British thermal units (Btu) in 2015 (EIA 2016). Biomass includes agricultural and forestry resources, municipal solid waste (MSW), and algae. For more than a decade, the U.S. Department of Energy (DOE) has been quantifying the potential of U.S. biomass resources, under biophysical and economic constraints, for production of renewable energy and bioproducts. The 2016 Billion-Ton Report: Advancing Domestic Resources for a Thriving Bioeconomy (BT16) evaluates the most recent estimates of potential biomass that could be available for new industrial uses in the future. BT16 consists of two volumes: Volume 1 (this volume) focuses on resource analysis—projecting biomass potentially available at specified prices. Volume 2 evaluates changes in environmental sustainability indicators— water quality and quantity, greenhouse gas emissions, air quality, soil organic carbon, and biodiversity—associated with select production scenarios in volume 1. The following is a summary of BT16, volume 1.

Contaminated sediments and other sites present a difficult challenge for environmental decisionmakers. They are typically slow to recover or attenuate naturally, may involve multiple regulatory agencies and stakeholder groups, and engender multiple toxicological and ecotoxicological risks. While environmental decision-making strategies over the last several decades have evolved into increasingly more sophisticated, information-intensive, and complex approaches, there remains considerable dissatisfaction among business, industry, and the public with existing management strategies. Consequently, contaminated sediments and materials are the subject of intense technology development, such as beneficial reuse or in situ treatment. However, current decision analysis approaches, such as comparative risk assessment, benefit-cost analysis, and life cycle assessment, do not offer a comprehensive approach for incorporating the varied types of information and multiple stakeholder and public views that must typically be brought to bear when new technologies are under consideration. Alternatively, multicriteria decision analysis (MCDA) offers a scientifically sound decision framework for management of contaminated materials or sites where stakeholder participation is of crucial concern and criteria such as economics, environmental impacts, safety, and risk cannot be easily condensed into simple monetary expressions. This article brings together a multidisciplinary review of existing decision-making approaches at regulatory agencies in the United States and Europe and synthesizes state-of-the-art research in MCDA methods applicable to the assessment of contaminated sediment management technologies. Additionally, it tests an MCDA approach for coupling expert judgment and stakeholder values in a hypothetical contaminated sediments management case study wherein MCDA is used as a tool for testing stakeholder responses to and improving expert assessment of innovative contaminated sediments technologies.

Abstract An examination of the variational formulations confirms the similarity between the incompatible displacement model and the assumed stress hybrid model that was pointed out by Irons in 1972. But the basic differences between the two are also identified. For 8‐node solid elements the assumed stress terms obtained through a rational procedure also agree with those deduced by Irons purely from his physical insight.

Traffic was studied upstream and downstream of a bottleneck that arose near a freeway lane drop near London, U.K. using archived high-resolution loop detector data. The bottleneck’s location and mean discharge flows were reproducible from day to day. Further, it is shown that the bottleneck’s discharge flow was about 10% lower than the prevailing flow observed prior to queue formation. Upon bottleneck activation, flow reductions occurring sequentially in time and space marked the passage of the backward-moving shock. Mean shock velocities ranged between 4.8 and 6.4km∕h (3 and 4 mph) as they traveled upstream from the bottleneck. During bottleneck discharge, oscillations arose in the queue and propagated upstream at nearly constant speeds of 17.6–19.2km∕h (11–12 mph). Flows measured at locations downstream of the bottleneck were not affected by these oscillations. These findings were corroborated using data from a freeway lane drop in Minneapolis, Minn. The analysis tools used for this study were curves of cumulative vehicle count, time mean speed and occupancy versus time. These curves were constructed using data from neighboring freeway loop detectors and were transformed in order to provide the measurement resolution necessary to observe the transitions between freely flowing and queued conditions and to identify important traffic features.

Abstract Somatotopic organization was demonstrated by means of microelectrode mapping studies of three somatic sensory nuclear regions in the raccoon medulla. Projections of peripheral receptive fields in the cuneate‐gracile nuclear complex occur iteratively in rostro‐caudal columns. These projections are organized into a detailed 3‐dimensional pattern, in contrast to the more diffuse intermingling of such projections in the spinal dorsal roots and columns. This indicates that afferent fibers are re‐sorted before synaptic termination. In the extensive representation of the volar hand, there are distinct subnuclei, delineated by intervening fiber laminae, each containing the projections from one of the forepaw digits. Units in the external‐cuneate nucleus responded only to stimulation of deeperlying tissues in anterior body regions. These projections were also somatotopically organized. Retrograde degeneration studies indicated that some cells, in that region where cuneate‐gracile adjoins external‐cuneate, may project through both the ipsilateral cerebellar peduncles and the contralateral midbrain. The spinal trigeminal nucleus adjoining the cuneate‐gracile complex displayed many characteristics similar to those of the latter. Neighboring, although anatomically distinct, regions contained projections from neighboring peripheral receptive fields.