bluuebunny/crossref_metadata_2025 huggingface dataset:
Species-specific trajectories of nitrogen isotopes in Indiana hardwood forests, USA
Authors: McLauchlan K. K. , Craine J. M.
Published: June 2011

Abstract. Humans have drastically altered the global nitrogen (N) cycle, and these alterations have begun to affect a variety of ecosystems. In North America, N deposition rates are highest in the Central US, yet there are few studies that examine whether N availability has been increasing to different tree species in the forests of the region. To determine the species-specific trajectories of N availability in secondary temperate forests experiencing high N deposition, we measured the N concentrations and composition of stable N isotopes in wood of four tree species from six hardwood forest remnants in Northern Indiana, USA. Annual nitrogen deposition rates averaged 5.8 kg ha−1 from 2000 to 2008 in this region. On average, wood δ15N values in Quercus alba have been increasing steadily over the past 100 yr. In contrast, wood δ15N values have been declining in three other hardwood species – Acer saccharum, Carya ovata, and Fagus grandifolia – over the same time period. The species-specific trends suggest a change in the partitioning of ammonium and nitrate among species, a change in nitrification rates, and/or offsetting changes in the dependence of species on mycorrhizal fungi. With no apparent net change in wood δ15N over the past century at the stand level, on average there appears to have been little change in N availability for these forests despite high levels of N deposition in the region.
Towards understanding how surface life can affect interior geological processes: a non-equilibrium thermodynamics approach
Authors: Dyke J. G. , Gans F. , Kleidon A.
Published: June 2011

Abstract. Life has significantly altered the Earth's atmosphere, oceans and crust. To what extent has it also affected interior geological processes? To address this question, three models of geological processes are formulated: mantle convection, continental crust uplift and erosion and oceanic crust recycling. These processes are characterised as non-equilibrium thermodynamic systems. Their states of disequilibrium are maintained by the power generated from the dissipation of energy from the interior of the Earth. Altering the thickness of continental crust via weathering and erosion affects the upper mantle temperature which leads to changes in rates of oceanic crust recycling and consequently rates of outgassing of carbon dioxide into the atmosphere. Estimates for the power generated by various elements in the Earth system are shown. This includes, inter alia, surface life generation of 264 TW of power, much greater than those of geological processes such as mantle convection at 12 TW. This high power results from life's ability to harvest energy directly from the sun. Life need only utilise a small fraction of the generated free chemical energy for geochemical transformations at the surface, such as affecting rates of weathering and erosion of continental rocks, in order to affect interior, geological processes. Consequently when assessing the effects of life on Earth, and potentially any planet with a significant biosphere, dynamical models may be required that better capture the coupled nature of biologically-mediated surface and interior processes.
Effects of antecedent soil moisture on runoff modeling in small semiarid watersheds of southeastern Arizona
Authors: Zhang Y. , Wei H. , Nearing M. A.
Published: June 2011

Abstract. Antecedent soil moisture prior to a rain event influences the rainfall-runoff relationship. Very few studies have looked at the effects of antecedent soil moisture on runoff modeling sensitivities in arid and semi-arid areas. This study examines the influence of initial soil moisture on model runoff prediction capability in small semiarid watersheds using model sensitivity and by comparing the use of antecedent vs. average long term soil water content for defining the model initial conditions for the modified Green-Ampt Mein-Larson model within the Rangeland Hydrology and Erosion Model (RHEM). Measured rainfall, runoff, and soil moisture data from four semiarid rangeland watersheds ranging in size from 0.34 to 4.53 ha on the Walnut Gulch Experimental Watershed in southeastern Arizona, USA, were used. Results showed that: (a) there were no significant correlations between measured runoff ratio and antecedent soil moisture in any of the four watersheds; (b) average sensitivities of simulated runoff amounts and peaks to antecedent soil moisture were 0.05 mm and 0.18 mm h−1, respectively, with each 1 % change in antecedent soil moisture; (c) runoff amounts and peaks simulated with long term average soil moisture were statistically equivalent to those simulated with measured antecedent soil moisture. The relative lack of sensitivity of modeled runoff to antecedent soil moisture in this case is contrary to results reported in other studies, and is largely due to the fact that the surface soil is nearly always very dry in this environment.
Refrigerated Trucking Revisited
Authors: Beilock Richard , Ciello James Del
Published: June 2011

Trucking is the dominant transport mode in the United States for foodstuffs, particularly those with high value and requiring controlled temperature and humidity. For example, 95% of all interstate produce shipments are by truck. To understand better this segment of the motor carrier industry, during the 1980s surveys were conducted of long-distance truckers exiting the Florida Peninsula. That work helped establish baseline data about the industry, including its structure, pricing, impacts of regulations, etc. After nearly 15 years, a similar survey was conducted in 2001-2002 of more than 1,600 drivers of long-distance refrigerated trucks. Issues addressed included: use of brokers and the Internet to arrange loads, importance of owner-operators and their ability to operate independently versus under lease to larger carriers, equipment replacement and utilization, and lumping.
A Comprehensive Approach for Rolling Stock Planning: Combining Train Performance Simulation and Life-Cycle Cost Analysis
Authors: Liu Rongfang (Rachel) , Song Albert C. , Nelson David O.
Published: June 2011

Rolling stock has a limited life span during which it can provide efficient service. Faced with today's budget constraints and economic slowdown, all railroad or transit operators will eventually face the following questions: What is the most suitable equipment available to replace the existing equipment for the particular service? What is the most economic way of procuring the required fleet?

To answer those questions, various railroad agencies and transit operators used diversified measures such as capacity demanded by the ridership forecast, performance afforded by the proposed equipment, or the operating and capital cost associated with certain rolling stock configurations. However, comprehensive analyses based on all three factors mentioned above are rare, even though it is agreed that all those factors affect railroad services simultaneously and they all should be considered in the rolling stock planning process.

To fill the gap, this paper describes a comprehensive approach to select long-term rolling stock for commuter services. This approach not only considers the performance of the proposed equipment but also evaluates the life cycle costs of the proposed fleet configuration. A case study of rolling stock planning for a commuter rail service is included to demonstrate the practical application of the suggested approach. Combining the train performance simulation (TPS) and life cycle cost (LCC) analysis, the proposed approach derives an optimal balance between service costs and service quality. Moreover, by incorporating the timing of the new equipment purchases into the life cycle cost, this approach further maximizes the return on capital investment for transit agencies.
The Disappearing Diagrams
Authors: Kahn Fritz R.
Published: June 2011

Railroads are ignoring the statutory and regulatory requirement that they file current system diagram maps with the Surface Transportation Board. As a result shippers and communities are denied advance notice of lines likely to be shut down or abandoned. Moreover, potential operators qualified to purchase and render service on such lines are unable to force their sales contemplated by the law without having to prove the inordinate service deficiencies of the railroads, nearly an impossible burden.
Effects of Driver Age and Dimensions of the Stop Sign on Braking Distance Performance at Stop-Controlled Intersections
Authors: Dissanayake Sunanda
Published: June 2011

Guidelines for the use of traffic control devices at stop-controlled intersections in the United States are provided in the Manual on Uniform Traffic Control Devices (MUTCD). Based on that, different dimensions of stop signs could be employed, even within the same jurisdiction. The study summarized in this paper investigated the effects of driver age and dimensions of stop signs on braking distance performance at stop-controlled intersections, while paying particular attention to older drivers. Data were collected at several stop-controlled intersections in non-residential areas in Hillsborough County, Florida, where three different sizes of stop signs (30", 36", and 48") were in use. Three driver age groups were also considered: older drivers, middle-age drivers, and young drivers. Statistical testing was used to find out whether the braking distances were different among driver age groups and also among different sizes of stop signs. Based on the observational data, it was found that older drivers had significantly longer braking distances for the largest size of the stop sign. Braking distances were also significantly different among the driver groups for the two larger sizes of the stop signs, but not for the smallest. In other words, older drivers see the larger sign and apply the brakes sooner resulting in longer braking distances. As such, the study recommends considering the replacement of smaller sizes of stop signs with the largest size in non-residential areas with a high older-driver population to increase safety at stop-controlled intersections.
An Econometric Analysis of Ocean Freight Rates for Grain Shipments from the United States to Major Importing Countries
Authors: Park Joon J. , Koo Won W.
Published: June 2011

This article uses a cross-sectional econometric model to evaluate structural changes and price differentials in ocean freight rates for grain shipments from U.S. ports to various major importing countries. Cost factors included are distance and the ship size, and competitive factors are shipping seasons, shipping frequencies, multiple destinations, commodity types, and characteristics of origins and destinations. Results suggest cost factors play a significant role in determining ocean freight rates, and the ocean shipping industry charges different rates by season and commodity. This study also indicates that ocean freight rate structures have changed during the 1987-1998 period.
The Balance Between Private and For-Hire Carriage and Trends in the Use of Large Trucks (1977 to 1997)
Authors: Burks Stephen V. , Monaco Kristen , Myers-Kuykindall Josephine
Published: June 2011

An analysis of data from 20 years (1977 – 1997) of the quinquennial Vehicle Inventory and Use Survey (VIUS), collected by the U.S. Census Bureau, indicates that the overall population of heavy freight vehicles grew at the same rate as real GDP, just under 3% per year. However, the total miles operated by vehicles of this type grew 50% more, 4.5%, which produced a very large cumulative increase, from 46.8 billion miles in 1977 to 111.6 billion in 1997. This was because of a 34% increase in the intensity of use of heavy freight vehicles, as measured by changes in their average annual miles of operation. The key patterns underlying these aggregate changes are analyzed by examining the trajectories of several subdivisions within trucking over the period, segregating the data by private versus for-hire carriage and geographic range of service. There are a number of interesting nuances, but the main underlying trend is a sharp increase in the specialization of for-hire carriage in long-haul operations, complemented by an increasing relative dominance of private carriage in local operations.
Investments Under Uncertainty in Air Transportation: A Real Options Perspective
Authors: Miller Bruno , Clarke John-Paul
Published: June 2011

Infrastructure investment decisions in air transportation are difficult because of long lead times, large capital expenditures and the technological, market and political uncertainties inherent in aviation. In such an environment, a flexible investment strategy is a means of managing risk. The central idea is to structure the investment so that it would benefi t from the upside potential if circumstances are resolved favorably, but would be protected from downside losses otherwise. In this paper, an evaluation methodology based on system dynamics and Monte Carlo simulation in a real options framework is utilized to evaluate different flexible infrastructure delivery strategies.
Value of Time for Commercial Vehicle Operators
Authors: Smalkoski Brian , Levinson David
Published: June 2011

Value of time was estimated for commercial vehicle operators in Minnesota to quantify the effects of spring load restrictions. A sample was constructed from several trucking industry sources to conduct a survey. Interviews were conducted using an adaptive stated preference (ASP) survey to derive an estimate to the nearest dollar.

A tobit model was fit to the data from the interviews to derive the estimate for value of time, $49.42 per hour. Variation in the distribution of values is explained in part by fleet operation: whether the firm operates as a for-hire carrier or a private carrier.
The Effects of Safety Practices, Technology Adoption, and Firm Characteristics on Motor Carrier Safety
Authors: Dammen Sarah J.
Published: June 2011

The theory of the firm suggests that firms should maximize profit by investing in safety until marginal cost is equal to the marginal benefit. This paper addresses motor carrier safety from the perspective of the firm, developing the theoretical framework for firm safety decisions. Additionally, this paper tests the relationship between firm safety performance and safety practices, new safety technologies, and firm marketing strategies. By testing the impact of the safety performance marketing strategy on carrier accident rates, it can be shown that firm managers have control over the safety performance of their firms through management decisions.
A Quantitative Evaluation of the Nighttime Visual Sign Inspection Method
Authors: Rasdorf William J. , Hummer Joseph E. , Vereen Stehanie C. , Cai Hubo
Published: June 2011

A research project to determine the appropriate sign inspection and replacement procedure was conducted at North Carolina State University and sponsored by the North Carolina DOT. The purpose was to determine the optimum strategy for sign inspection and replacement under different conditions to respond to the pending retroreflectivity requirements. This paper reports on a spreadsheet tool developed to quantitatively evaluate the effectiveness of different sign inspection and replacement scenarios. The spreadsheet was designed for yellow and red engineer-grade sign sheetings, and takes into account sign vandalism and knock-downs as well as normal sign aging. The spreadsheet provides estimates of the number of signs in place that would not meet the minimum retroreflectivity standard and the cost of the sign inspection and replacement program.

The results from a number of trials of the spreadsheet show that agencies that generally conform to the key assumptions made to build the spreadsheet should consider replacing all signs every seven years, as that insures that no aged signs are in place at a relatively low cost. If total replacement is not possible, an inspection program using retroreflectometers every three years appears very competitive in its effectiveness with a program using typical visual inspection rates each year. The retroreflectometers appear to allow fewer deficient signs, while the typical visual inspection program costs are lower for a given vandalism rate. More conservative visual sign replacement rates do not appear to offer distinct advantages, because typical replacement rates with visual inspections every two or three years allow relatively high numbers of deficient signs to remain on the roads.
Leading Transportation Indicators: Forecasting Waterborne Commerce Statistics Using Lock Performance Data
Authors: Thoma Mark A. , Wilson Wesley W.
Published: June 2011

This paper develops and applies a forecasting model for transportation data based on the leading economic indicators literature. The specific application is to forecast river tonnages. Waterborne commerce data reflect tonnages of commodities moved on various rivers and in various directions. They are released after the Lock Performance Monitoring System data which reflect tonnages moving through specific locks. The model presented here forecasts waterborne commerce data from lock performance data. The results suggest that even a very simple model can provide precise forecasts.
Forecasting Cycles in the Transportation Sector
Authors: Yao Vincent W. , Sloboda Brian W.
Published: June 2011

This paper predicted fluctuations in the transportation sector using leading indicators. From 25 initial candidates, we selected seven leading indicators, using various screening techniques and modern time series models. A composite leading index was constructed and found to perform well in predicting transportation reference cycles. The leading index signals downturns in the transportation sector 10 months ahead and upturns six months ahead on average. The index predicted the latest recession in transportation with a lead of 20 months. The analysis also confirms the predictive contents of the composite leading index (CLI) in relation to transportation growth cycles. These evaluation criteria ensure accurate forecasts of the general state of the transportation sector in a timely fashion.
Benefits, Costs, and Financing of Truck-Only Highway Lanes
Authors: Forkenbrock David J. , Hanley Paul F.
Published: June 2011

As increasing amounts of intercity freight are transported by trucking firms, the possibility of constructing truck-only lanes along selected rural Interstate highways warrants consideration. On heavily traveled sections, there is potential for improvements in safety and productivity if such lanes were added. In this paper, we explore the conditions under which investment in truck-only lanes could be considered and what sorts of benefits may accrue to both occupants of passenger vehicles and to operators of heavy trucks. Then we examine the available evidence regarding the nature and magnitude of these benefits to gain insight into the willingness of highway users to pay for these lanes. We conclude that the willingness to pay for truck-only lanes on the part of occupants of passenger vehicles appear to be quite limited and that support for these lanes on the part of trucking firms is likely to depend upon their being allowed to operate longer-combination vehicles (LCVs) on them. Trucking firms could be assessed tolls to travel in truck-only lanes, with these tolls representing some fraction of the increased productivity gained through being allowed to operate LCVs. Finally, we pose several questions that would need to be answered before an investment in truck-only lanes might be considered along a given Interstate segment.
Operational and Safety Evaluation of Freeways with Posted Minimum Speed Limit
Authors: Muchuruza Victor , Mussa Renatus
Published: June 2011

An operational and safety evaluation was conducted in relation to the posting of the minimum speed limit of 40 mph and the maximum speed limit of 70 mph on the Florida rural interstate freeway system. The results showed that 57% of the recorded vehicles exceeded the maximum speed limit. Additionally, while only 0.14% of recorded vehicles had speeds below the 40 mph posted minimum speed limit, 9% of crash-involved vehicles were estimated to have speeds below 40 mph. The overrepresentation of slow-moving vehicles in the crash data suggests that even a small proportion of under-40-mph vehicles can have negative implications on safety. Thus, regulation of vehicle speeds at the lower end of the speed distribution is equally important. The second order polynomial model developed to estimate the risk of a vehicle being involved in a crash as a function of the speed deviation from the mean speed of traffic indicated that the minimum risk occurred when the driving speed was 8 mph above the mean speed, equal to the 85th percentile speed observed in the field. Further, the Poisson regression modeling indicated that the difference between the 85th and 15th percentile speeds had a positive effect on crashes.
Specifying Automated Pavement Condition Surveys
Authors: Lindly Jay K. , Bell Frank , Ullah Sharif
Published: June 2011

Between 1994 and 2004, the number of U.S. and Canadian Departments of Transportation (DOTs) using automated techniques to record pavement surface distresses increased fourfold to approximately 30. Twenty more U.S. state agencies can be expected to automate techniques in the near future. The typical agency will use vans traveling at highway speeds to automatically measure roadway roughness, rutting, joint faulting, and cracking. This paper describes the upgrade of the Alabama Department of Transportation's automated pavement condition data survey specifications. The objective of the paper is to provide information concerning costs, standards, and survey methodology that will be valuable to other DOTs as they add automation to their systems.
Multi-Measure Quality Analysis of Weather Forecasts Used for Winter Highway Maintenance Purposes
Authors: Dissanayake Sunanda , He Wei , Landman Dean , Knapp Mary
Published: June 2011

State Departments of Transportation spend a considerable portion of their winter maintenance budgets getting accurate weather forecasts that are essential for proactive operations and are interested in getting the best value for their money. With that intention, the Kansas Department of Transportation obtained weather forecasts from three commercial weather data providers for four selected locations within the state of Kansas. This paper presents a quality analysis of those forecasts to identify the most accurate and reliable provider. In doing so, researchers used the prediction of frost events as the performance measure. Several different measures that were capable of quantifying the selected attributes (reliability, accuracy, and skill) were used to evaluate different forecasts for each location and for combined data.
The Journey to Work: 25 Years on the Jamaicaway
Authors: Martland Carl D.
Published: June 2011

More than 600 observations were recorded for the author's home-to-work trip for the same route from Boston to Cambridge, Mass., over the period 1980 to 2004. With this data, it is possible to graph the pattern of travel times and travel time reliability as a function of departure times during the morning rush hour. The image of rush hour performance that emerges from this study is more complex than what is often used in network models or abstract economic analysis. For example, as rush hour progresses, variability increases even though expected travel times start to decline. There may also be lulls in rush hour, i.e. intervals of 10-15 minutes when expected trip times and reliability temporarily improve. This type of performance cannot realistically be modeled as a linear function of traffic volume, nor can it be approximated using a steady state queuing analysis. It will be far better to view rush hour performance as a steady state cyclical queuing phenomenon: every day may start afresh, but expected conditions on next Tuesday at 8:30 am are likely to be similar to conditions last Tuesday at that time.Over the 25-year period, there was surprisingly little change in rush hour performance on this congested urban route. Average travel times were mostly in the range of 25-27 minutes with a standard deviation of three to four minutes. There was some spreading of the peak, especially during periods involving major construction, but performance in the most recent period was actually equivalent to performance in the 1980s despite an increase of about 10% in traffic volume. Variability in trip times is mostly related to variability in the delays associated with the most congested
County-Level Impacts of Rail Line Abandonments: A Kansas Case Study
Authors: Sanderson James , Babcock Michael W.
Published: June 2011

This article describes the use of econometric panel data techniques to estimate the effects of rail line abandonments at the county level. The article presents the economic theory that indicates how abandonments will affect local communities. Data were collected on line abandonments and several economic measures for counties in Kansas. Panel data estimation techniques were used to provide estimates of the effects for rural, urban and metropolitan counties. Results indicate that abandonments produce an initial period of economic growth that may be temporary for some counties. Results also indicate that any adverse impacts appear with a time lag of a few years.
Choice of Aircraft Fleets in the U.S. Domestic Scheduled Air Transportation System: Findings from a Multinomial Logit Analysis
Authors: Bhadra Dipasis
Published: June 2011

The National Airspace System (NAS) in the United States had an inventory of 5,156 big jets at the end of December 2002, of which 4,085 were narrow bodies, and 1,071 were wide bodies. In addition, there were 1,180 regional jets and 660 turboprops in the system at that time. Empirical research reveals that there is a critical link between the flow of scheduled passenger services and the choice of aircraft used by the airlines in serving market pair demand. This relationship can be empirically retrieved without detailed knowledge of airlines' behavior and used for analyzing traffic patterns in the NAS. Using the T100 segment data from the first two quarters of 2004, a multinomial qualitative choice model is developed in this paper. This framework establishes empirical linkages among aircraft choice, and passenger flows, distance, types of airport hubs, network and time of the year. Estimated models demonstrate that both passengers and distance play important roles in selecting types of aircraft. Overall, the model is capable of predicting exact choices 51% of the time; with some flexibility of making a one-off mistake, the model is capable of making almost nine out of 10 choices correctly. Using the estimated coefficients from the qualitative choice model and varying assumptions (number of passengers, in particular), forecasts of aircraft operations by market segments and the fleet mix can easily be generated. These forecasts can then be used to understand the performance of the U.S. NAS.
Implementing Congestion Pricing on Metropolitan Highway Networks with Self-Financing Public-Private Partnerships
Authors: DeCorla-Souza Patrick
Published: June 2011

This paper presents a new public-private partnership model for road pricing applications either at the facility level or on a region-wide highway network. The model addresses issues of monopoly power and efficiency of delivery of transportation services. The paper also addresses issues relating to financial self-sufficiency of integrated multimodal pricing strategies and assesses the financial self-sufficiency of an ambitious region-wide pricing concept that integrates multimodal mobility choices.
The Operational Impacts of Government Restructuring of the Airline Industry
Authors: Schrega Carl A.
Published: June 2011

In July 2000, the Civil Aviation Administration of China (CAAC) called for the consolidation of the 10 state-owned air carriers into three groups, headed by Air China, China Eastern, and China Southern. A few months later in November 2000, the State Council of China mandated that this consolidation be accomplished by the third quarter of 2001. As part of this mandate, the CAAC yielded its management control of air carriers with its focus now being on safety and regulatory issues. Furthermore, the CAAC was required to divest itself of assets held in many of the state-owned airlines and its interests in more than 120 airports around China, except Beijing Capital Airport.

Utilizing data from the International Civil Aviation Organization for 2003 and 2004, this study investigates the operational impacts of this industry restructuring. The relative operational efficiency of Air China, China Eastern, and China Southern is compared to a sample of Asian, European and United States flag carriers. Data envelopment analysis is utilized to derive efficiency scores for individual airlines. The operational efficiency model used in this study is derived from that utilized by Schefczyk (1993). The underlying structural drivers of efficiency are then investigated via a tobit analysis with implications for managerial policy discussed.
Comparison of TRANSIMS' Light Duty Vehicle Emissions with On-Road Emission Measurements
Authors: Jeihani Mansoureh , Ahn Kyoungho , Hobeika Antoine G. , Sherali Hanif D. , Rakha Hesham A.
Published: June 2011

The Transportation Analysis and Simulation System, TRANSIMS, contains a vehicle emissions module that estimates tailpipe emissions for light and heavy-duty vehicles and evaporative emissions for light-duty vehicles. This paper describes and validates the TRANSIMS emission module and compares its emission estimates to on-road emission-measurements and other state-of-the-art emission models. The trend of the emissions estimated in thirteen different runs in each model are compared. The results indicate that the TRANSIMS model provides consistent trends of estimated carbon monoxide (CO) and hydrocarbons (HC) with field data trends and inconsistent trends of estimated nitrogen lxides (NOx). However, the magnitude of the emission estimated in TRANSIMS is closer to the field data than for other models.
Modeling Willingness-to-Pay Values for Rural Bus Attributes Under Different Trip Purposes
Authors: Phanikumar C. V. , Maitra Bhargab
Published: June 2011

Modeling Willingness-to-Pay Values for Rural Bus Attributes Under Different Trip Purposes
Analysis of Traveler Characteristics by Mode Choice in HOT Corridors
Authors: Burris Mark W , Figueroa Carlos F.
Published: June 2011

This research examined travelers who have a vast array of travel options, including some rather unique ones: HOV3+ in an HOV lane, HOV2+ in an HOV lane off-peak, HOV2 plus a $2.00 toll in an HOV lane during the peak, and casual carpooling (slugging). Travelers using all these modes were surveyed in 2003, and significant differences between the groups of travelers were observed, providing some understanding of travel behavior when faced with these travel options. In the study, particular effort was spent on examining the characteristics of travelers who choose to travel as HOV2 carpools during peak periods and pay a $2.00 toll. This group of travelers was found to contain significantly more well-educated females with high household incomes on school related trips. The proximity of private schools near the terminus of the HOV lane probably contributed significantly to this result. Due to the array of mode choices available to these travelers, surveying all these groups was challenging and, therefore, the methodology employed in survey development and administration is also detailed in this paper.
Aviation System Performance During the Summer Convective Weather Season
Authors: Wright Kenneth
Published: June 2011

This paper analyzes recent trends related to delays, airborne holding and diversions in the National Airspace System (NAS) during the summer convective weather season. A weather variable is introduced to help analyze these performance metrics in a way that factors out differences in the location and intensity of thunderstorms. Regression analysis indicates a nearly 50% increase in flights delayed more than an hour from summer 2003 to 2005. The increase in delay is associated with a growing concentration of flights at busy hub airports over the past five years.
The United States-European Union Open Aviation Area: The American Perspective
Authors: Hofer Christian , Dresner Martin
Published: June 2011

This paper presents a comprehensive analysis of current United States-European Union (U.S.-E.U.) aviation relations. Following a brief historical review, the proposed North-Atlantic Open Aviation Area is discussed. Specifically, the associated economic benefits are assessed, and the causes of the current deadlock in U.S.-E.U. negotiations are analyzed. Particular attention is paid to the interests and actions of U.S. stakeholders, most notably U.S. airlines, labor organizations, the Department of Transportation and Congress.
Stakeholder Contributions to Container Port Capacity: A Survey of Port Authorities
Authors: Maloni Michael J. , Jackson Eric C.
Published: June 2011

Given recent concerns about North American port congestion, this paper examines stakeholder involvement in expanding port capacity to meet significant volume growth. North American container port authorities were surveyed to identify key capacity factors and subsequent participation requirements by stakeholders such as terminal operators, longshore labor, railroads, steamship lines, truckers, and government. The resulting analysis indicates port frustration with participation currently offered by all stakeholders, especially the federal government and railroads. Such results further validate the requirement for a multi-stakeholder approach to port capacity expansion and suggest the need for national freight policy and planning leadership.
Estimation of Satisfied Customers in Public Transport Systems: A New Methodological Approach
Authors: Morfoulaki Maria , Tyrinopoulos Yannis , Aifadopoulou Georgia
Published: June 2011

This paper addresses quality considerations in public transportation systems and, in particular, the relation between quality of public transport service and customer satisfaction. Its aim is to provide insights into the factors that affect transit-rider satisfaction and to present a model to calculate the probability of customer satisfaction. The proposed model identifies the most important attributes of public transport service quality that can be used for service planning.
Railroad Capital Stock Changes in the Post-Deregulation Period
Authors: Bereskin C. Gregory
Published: June 2011

This paper involves the estimation of a model of railway road and equipment capital stocks and the changes in their levels that have occurred since 1983. The model is based on balancing the level of investment and the level of degradation of the capital stocks to create a data series for roadway capital and for equipment capital. A two-stage least squares errors in variables model is applied. This is appropriate as degradation and exact constant dollar investment are not directly observable. Results obtained from the model indicate that Class I railroads have increased their absolute capital stock levels over the period examined. This holds for both roadway and equipment capital although roadway capital has increased at a somewhat faster rate.
Cross-Cultural Factors and Corporate Governance Transparency in Global Airline Strategic Alliances
Authors: Giapponi Catherine C. , Scheraga Carl
Published: June 2011

This paper argues that a critical dimension in understanding the factors that inhibit the effectiveness and benefits of airline alliances is corporate transparency. Specifically, the issue of transparency in corporate governance is considered. Corporate governance is the set of institutional arrangements affecting corporate decision making, and deals with the relationship among various participants in determining the direction and performance of corporations.

However, airline strategic alliances span an array of national cultures which influence the development of such relationships. The impact of national culture as a determinant of governance transparency is also investigated in this paper. This study draws on the literature which examines the impact of national culture on international joint ventures and governance systems. National cultures are described by Hofstede's five dimensions of power distance, uncertainty avoidance, individualism, masculinity, and temporal orientation.

Governance transparency is investigated by the examination of corporate annual reports. Thus, this study investigates not only the level of corporate governance transparency demonstrated by participants in each of the three major airline alliances, but the relationship between said governance transparency and the cultural identity of each of the participants.
Assessing the Effects of Road Pricing on an Industry: The Grain Handling and Transportation System in Saskatchewan
Authors: Larson Erik K. , Nolan James F.
Published: June 2011

This research evaluates the merits of road pricing scenarios affecting a single industry almost exclusively – grain movement on the rural road network in the west central region of the Canadian province of Saskatchewan. Policies in the Canadian grain handling and transportation industry have led to increased use of rural roads, accelerating road deterioration in the region. Using a simulated optimization framework to compare road pricing schemes, we find that a policy of differential road pricing based on known road maintenance costs generates the lowest total social costs. The differences between the simulated social costs in the pricing scenarios are surprisingly small.
An Interactive Tool to Compare and Communicate Traffic Safety Risks: TrafficSTATS
Authors: Fischbeck Paul S. , Gengler Barbara , Gerard David , Weinberg Randy S.
Published: June 2011

TrafficSTATS (www.traffic-stats.us) is a publicly-available, interactive, web-based query tool that provides estimates of passenger vehicle and other traffic safety risks. Using "cube" database technology, TrafficSTATS houses publicly-available government data on traffic fatalities from the Fatality Analysis Reporting System (FARS) and personal travel behavior from the National Household Travel Survey (NHTS) and calculates risk statistics in real time for user-specified queries. We describe the motivation for developing the tool, explain the technology developed to store the data and facilitate the queries, and provide a series of examples of the types of comparisons that can be made quickly and efficiently.
The Introduction of Dynamic Features in a Random-Utility-Based Multiregional Input-Output Model of Trade, Production, and Location Choice
Authors: Huang Tian , Kockelman Kara M.
Published: June 2011

This study introduces dynamic features into the random-utility-based multiregional input-output (RUBMRIO) model. The RUBMRIO model predicts interzonal trade and travel patterns, as well as business and household location choices, using consumption and production process data. It equilibrates production and trade, labor markets, and transportation networks simultaneously. Multinomial logit models predict the origins of productive inputs, including commute behaviors (for the input of labor).

With household locations and expenditures/incomes relatively well-known for the very near future, one can predict current trade patterns by making household consumption, as well as (foreign and domestic) export demands, exogenous to the model, resulting in short-term predictions. The long-run equilibrium, wherein household locations and consumption patterns are endogenous, will differ from this short-term solution.
Spatial Investigation of Mineral Transportation Characteristics in the State of Washington
Authors: Khachatryan Hayk , Jessup Eric L.
Published: June 2011

This study investigates the spatial relationships between construction aggregate shipments and the per axle payload weights of trucks as they pertain to highway deterioration in the state of Washington. A previous study investigated the transportation characteristics of mined aggregates using a spatial autoregressive model, where a significant positive relationship between payload weights and shipment distances was established. This paper expands the previous study by assessing the contribution of aggregate hauling trucks to pavement deterioration using per-axle loads by truck configuration.

Results showed a positive relationship between weights per axle load and several shipment distance categories. According to the well-established per axle weight and pavement damage relationship, incremental changes in per axle payload weights resulting from longer shipment distances clearly suggest that longer haulage increases the magnitude of pavement deterioration. This direct relationship between road impact and the distance hauled emphasizes the importance of the proximity of mine sites to different end users.
Opening Up African Skies: The Case of Airline Industry Liberalization in East Africa
Authors: Irandu Evaristus M.
Published: June 2011

The three member states of the East African Community (EAC) have made great efforts in modernizing their air transport industry in order to meet the increased demand for international tourism and horticultural export trade. The policy adopted by the sub-region, at independence, to regulate the airline industry was the bilateralism approach with emphasis on reciprocity. Such a policy became a bottleneck in the development of the air transport industry in the sub-region. It became apparent that the EAC member states needed efficient air services and not airlines that served mainly as status symbols. However, the last decade witnessed the liberalization of the aviation sector in the sub-region. This liberalization process is part of a proactive policy to encourage global investment in the sub-region. This has led to the adoption of the Yamoussoukro Decision, which calls for the opening of the African skies. This paper, therefore, critically discusses the process of the airline industry liberalization and its prospects for success in the sub-region.
Determinants of Motor Vehicle Fatalities: A Kansas Case Study
Authors: Babcock Michael W. , Zlatoper Thomas J. , Welki Andrew M
Published: June 2011

This paper analyzes the determinants of motor vehicle fatalities in Kansas. The objectives of the study include the following:

* Conduct a literature review of motor vehicle safety studies.
* Formulate a theoretical model of the determinants of motor vehicle fatalities.
* Estimate the statistical significance of the various determinants.
* Compare the empirical results of the study to other recent state studies of motor vehicle fatalities.

The unemployment rate had the expected inverse relationship to fatalities but was statistically significant in only two of seven estimated models. Alcohol consumption and the speed limit on rural interstate highways had the expected positive relationship to fatalities. Other variables that were statistically significant included Kansas seat belt law dummy, the proportion of young and old drivers to the rest of the Kansas population, and the ratio of rural to urban driving. The study measured the effect of three measures of highway safety law enforcement on fatalities: Kansas police per 10,000 population, Kansas police per 100 miles of road, and Kansas per capita expenditure for police protection. All three had the expected negative sign and were highly significant.
Creation of Truck Axle Load Spectra Using Weigh-in-Motion Data
Authors: Jiang Yi , Li Shuo , Nantung Tommy , Mangold Kirk , MacArthur Scott A.
Published: June 2011

To assure a smooth transition from the existing pavement design methods to the new mechanistic-empirical design method in the Indiana Department of Transportation, a study was conducted to create truck traffic inputs and axle load spectra of major interstate and state-owned highways in Indiana. The existing pavement design method is based on the equivalent single-axle loads (ESAL), which converts wheel loads of various magnitudes and repetitions to an equivalent number of "standard" or "equivalent" axle loads. The new design method uses axle load spectra as the measure of vehicle loads on pavements. These spectra represent the percentage of the total axle applications within each load interval for single, tandem, tridem, and quad axles. In this study, the truck traffic and axle load spectra were developed based on the historical traffic data collected at 47 sites with weigh-in-motion technology. The truck traffic information includes hourly, daily, and monthly distributions of various types of vehicles and corresponding adjustment factors, the distributions of the number of axles of each type of truck, the weights of the axles, the spaces between the axles, the proportions of vehicles on roadway lanes, and the proportions of vehicles in driving directions. This paper presents the truck traffic and axle load spectra generated from the weigh-in-motion sites as required by the new pavement design method.
Improving On-Time Performance for Long-Distance Passenger Trains Operating on Freight Routes
Authors: Martland Carl D.
Published: June 2011

This paper discusses on-time performance (OTP) for long-distance passenger trains operating over tracks that are owned and operated by freight railroads. OTP is addressed primarily from the point of view of the host railroad. A brief literature review identifies practices that are commonly used by railroads and other modes to develop and implement achievable schedules. Analysis of travel time, train delay and other data for Amtrak trains operating on CSXT's I95 Corridor documents actual levels of reliability and the primary causes of poor OTP. Comparison of performance for passenger trains and various classes of freight trains demonstrates that Amtrak trains operate much faster and more reliably than CSXT's trains. Potential means of improving the OTP of Amtrak trains are discussed. While providing high quality track with sufficient capacity is the long-run solution for upgrading OTP, a short-run solution is to base schedules on past performance ("experience-based scheduling"). After Amtrak increased the schedule of the Auto Train by one hour in 2006, OTP improved from less than 10% in early 2006 to 82% for the first half of 2008. Analysis of the travel time distributions of the other long-distance Amtrak trains operating on CSXT's I95 Corridor from 2004 to 2008 indicates that a similar schedule increase would also have brought these other trains close to Amtrak's goal of 80% OTP. Schedules that reflect track maintenance requirements and other known seasonal and weekly factors would allow further improvements in measured OTP. Additional measures of performance concerning the probability and extent of late arrivals would be beneficial to travelers in planning their trips.
Texas-Mexico Cross Border Truck Operations: Are Mexican NAFTA Trucks Unsafe?
Authors: West Jason , Harrison Robert
Published: June 2011

Texas Department of Public Safety (DPS) border safety inspection facilities (BSIF) have been in operation, in temporary and permanent forms, since 2001. This paper presents inspection results on trucks inspected at Texas BSIFs from 2003 to 2006, comprising over 326,000 vehicle inspection records. Analysis indicated that Mexico domiciled trucks have lower out-of-service rates than U.S. trucks at most Texas/Mexico border crossings. This finding is noteworthy since border (drayage) vehicles are older on average than typical Texas highway trucks and counters the opinion that trucks from Mexico are unsafe and therefore should not be allowed to enter the U.S.