TRANSPORTATION AND LOGISTICS

A bridge deterioration model is estimated from the National Bridge Inventory that explains and forecasts future condition as a function of bridge material, bridge design, operating rating classification, average daily traffic, the state where the bridge is located, and the age of the bridge. Over the 95-year analysis period, the rate of bridge deterioration with age is a third-order polynomial function. However, the relationship between condition and age is approximately linear until age 65. Holding all else constant, a bridge substructure in the Northern Plains loses approximately one-half of a condition rating point every 13 years until age 65.

Passenger Car Equivalent (PCE) is essential for transportation engineering to assess heavy vehicles’ (HV) impact on highway operations and capacity planning. Highway Capacity Manual 2010 (HCM 2010) used PCE values and percent of heavy vehicles to account the impacts on both highway planning and operation, however, PCE values in the latest version of HCM derived based on the steady and balanced two-lane-two-way (TLTW) traffic flows. The objective of the study is to identify PCE values for TLTW highway at various traffic volume with an emphasis on congestion conditions. This study introduces an analytical model, combining a headway-based and a delay-based algorithms, for estimating PCEs of HV on a TLTW highway. This study contributes to the literature by providing relationships among PCE, the traffic volume level (TVL) of both lanes, and the TVL duration on a TLTW highway. Traffic volume was categorized into five levels: TVL A (<250 pc/h), TVL B (250–375 pc/h), TVL C (375–600 pc/h)...

On-demand shared mobility services such as Uber and microtransit are steadily penetrating the worldwide market for traditional dispatched taxi services. Hence, taxi companies are seeking ways to compete. This study mined large-scale mobility data from connected taxis to discover beneficial patterns that may inform strategies to improve dispatch taxi business. It is not practical to manually clean and filter large-scale mobility data that contains GPS information. Therefore, this research contributes and demonstrates an automated method of data cleaning and filtering that is suitable for such types of datasets. The cleaning method defines three filter variables and applies a layered statistical filtering technique to eliminate outlier records that do not contribute to distributions that match expected theoretical distributions of the variables. Chi-squared statistical tests evaluate the quality of the cleaned data by comparing the distribution of the three variables with their expect...

Highway-rail grade crossing (HRGC) crashes continue to be the major contributors to rail causalities in the United States and have been intensively researched in the past. Data-mining models focus on prediction while dominant general linear models focus on model and data fitness. Decision makers and traffic engineers rely on prediction models to examine at-grade crash frequency and make safety improvement. The gradient boosting (GB) model has gained popularity in many research areas. In this study, to fully understand the model performance on HRGC accident prediction performance, the GB model with functional gradient descent algorithm is selected to analyze crashes at highway-rail grade crossings (HRGCs) and to identify contributor factors. Moreover, contributors’ importance and partial-dependent relations are generated to further understand the relationship of identified contributors and HRGC crash likelihood to concur “black box” issues that most machine learning methods face. Fur...

The remarkable mechanical properties and piezo-responses of carbon nanotubes (CNT) makes this group of nanomaterials an ideal candidate for use in smart cementitious materials to monitor forces and the corresponding structural health conditions of civil structures. However, the inconsistency in measurements is the major challenge of CNT-enabled smart cementitious materials to be widely applied for force detection. In this study, the modified tapioca starch co-polymer is introduced to surface treat the CNTs for a better dispersion of CNTs; thus, to reduce the inconsistency of force measurements of the CNTs modified smart cementitious materials. Cement mortar with bare (unmodified) CNTs (direct mixing method) and surfactant surface treated CNTs using sodium dodecyl benzenesulfonate (NaDDBS) were used as the control. The experimental results showed that when compared with samples made from bare CNTs, the samples made by modified tapioca starch co-polymer coated CNTs (CCNTs) showed high...

This paper proposes a mathematical model, the competing risks method, to investigate highway-rail grade crossing (HRGC) crash frequency and crash severity simultaneously over a 30-year period. The proposed competing risks model is a special type of survival analysis to accommodate the competing nature of multiple outcomes from the same event of interest; in this case, the competing multiple outcomes are crash severities, while event of interest is crash occurrence. Knowledge-gain-based benefits to be discovered through the application of this model and 30-year dataset are as follows: (1) a straightforward and integrated one-step estimation process that considers both crash frequency and severity likelihood in the same model, so direct hazard ranking considering both crash frequency and severity likelihood is possible; (2) interpretative effects of identified covariates from both the direction and magnitude perspectives; and (3) the long-term cumulative effect of contributors with th...

Investments in local roads in North Dakota to support agricultural logistics are estimated with a detailed model that predicts flows from 1,406 crop-producing zones to 317 elevators and plants, and forecasts improvements and maintenance costs for paved and unpaved roads. The study finds that (1) the average farm-to-market trip distance has increased from 12 miles in 1980 to 26 miles in 2009, (2) the estimated resurfacing cost per mile for agricultural distribution routes is 40% greater than for non-agricultural routes, and (3) the estimated cost to maintain acceptable service levels on county and local roads is roughly double historical funding levels.

The platform of a microscopic traffic simulation provides an opportunity to study the driving behavior of vehicles on a roadway system. Compared to traditional conventional cars with human drivers, the car-following behaviors of autonomous vehicles (AVs) and connected autonomous vehicles (CAVs) would be quite different and hence require additional modeling efforts. This paper presents a thorough review of the literature on the car-following models used in prevalent micro-simulation tools for vehicles with both human and robot drivers. Specifically, the car-following logics such as the Wiedemann model and adaptive cruise control technology were reviewed based on the vehicle’s dynamic behavior and driving environments. In addition, some of the more recent “AV-ready (autonomous vehicles ready) tools” in micro-simulation platforms are also discussed in this paper.

This study seeks Q5 to identify the contributing factors affecting commercial truck crash severity using 2010 to 2016 18 North Dakota and Colorado crash data provided by the Federal Motor Carrier Safety Administration. To fulfill a 19 gap of previous studies, broad considerations of company and driver characteristics, such as company size and 20 driver's license class, along with vehicle types and crash characteristics are researched. Gradient boosting, a 21 data mining technique, is applied to comprehensively analyze the relationship between crash severities and a 22 set of heterogeneous risk factors. Twenty-five variables were tested and twenty-two of them are identified as 23 significant variables contributing to injury severities, however, top 11 variables account for more than 80% of 24 injury forecasting. The relative variable importance analysis is conducted and furthermore marginal effects of 25 all contributing factors are also illustrated in this research. Several factors such as trucking company attributes 26 (e.g., company size), safety inspection values, trucking company commerce status (e.g., interstate or intrastate), 27 time of day, driver's age, first harmful events, and registration condition are found to be significantly associated 28 with crash injury severity. Even though most of the identified contributing factors are significant for all four levels 29 of crash severity, their relative importance and marginal effect are all different. Findings in this study can be 30 helpful for transportation agencies to reduce injury severity, and develop efficient strategies to improve safety.

Highway-rail grade crossing safety (and the prevention of accidents) is a priority in terms of both highway and railroad safety. Highway-rail crossing accidents often cause severe impacts in terms of fatalities, personal injuries and property damage. The damage cost and disruption to both roads and railroads are often significant (Evans, A.W., 2011; Salmon, Paul M., 2013). In 2014, there were 1,873 crashes reported at highway-rail crossings across the U.S., and those accidents resulted 239 deaths and 703 injuries (Federal Railroad Administration (FRA), 2015). Concerns about crashes at highway-rail crossings have increased for different agencies because it is commonly agreed that both highway and rail traffic levels increase the occurrence and severity of accidents (

The objectives of this paper are to (1) quantify the effects of age and other key factors on bridge deterioration rates, and (2) provide bridge managers with strategic forecasting tools. A model for forecasting substructure conditionisestimated from the National Bridge Inventory that includes the effects of bridge material, design load, structural type, operating rating, average daily traffic, water, and the state where the bridge is located. Bridge age is the quantitative independent variable. The relationship between age and substructure condition is a fourth-order polynomial. Some of the key findings are: (1) a bridge substructure is expected to lose from 0.52 to 0.11 rating points per decade as it ages from 10 to 70 years; (2) levels of deterioration increase significantly as the material changes from concrete, to steel, to timber; (3) slab bridges have lower levels of deterioration than other structures; (4) bridges that span water have lower condition ratings; (5) bridges with higher operating ratingshave higher condition ratings; and (6) substructure condition ratings vary significantly among states.

North Dakota currently designs roads based on the AASHTO Design Guide procedure, which is based on the empirical findings of the AASHTO Road Test of the late 1950s. However, limitations of the current empirical approach have prompted AASHTO to move toward the new mechanistically based pavement design procedure described in the Mechanistic Empirical Pavement Design Guide (MEPDG), which was released to the public for review in 2004 under NCHRP Project 1-37A. MEPDG combines mechanistic and empirical methodology and provides more realistic characterization of in-service pavements. Its mechanistic approach is both more thorough and more computationally complex than the existing AASHTO design method, and as a result the method can require an extensive number of detailed material, foundational, traffic, and environmental inputs. This and other factors can present a challenge to agencies wishing to implement the new method. Because AASHTO has adopted the MEPDG and highway agencies across th...

The rise of transportation network companies (TNCs) in recent years has revolutionized urban transportation across the globe. Most noticeably, the increased popularity of TNC services coincides with the declining trend of public transit ridership in the U.S. The impact of TNCs on urban public transit needs to be carefully evaluated in light of the potential implications of any future policy changes in transit funding and planning. Using top 50 U.S. agency-level data from 2007 through 2017, this study examines the effect of TNCs and transit effectiveness on public transit ridership in the U.S. We find that (1) transit effectiveness of both bus and rail transits declined over the study period; (2) TNC availability increased rail transit ridership in 2015; (3) transit effectiveness was highly significant for public transit, and when examining its effect year-by-year, rail transit effectiveness trumped TNC availability; (4) TNCs are neither a complement nor a substitute of bus transit.

I empirically examine the effects of bankruptcy protection (Chapter 11) on airfares in the U.S. domestic airline industry using cross sectional air tickets data from 2001:Q1 through 2012:Q4. A hedonic price model was developed to identify the determinants of airfares. The results indicate that, airfares charged by a bankrupt airline are approximately 4% lower than airfares of other airlines that are not in bankruptcy, ceteris paribus. Individually, bankrupt airlines lower their airfares as much as 16-19% during bankruptcy protection. Furthermore, it is evident that low cost carriers (LCCs) have significantly lower airfares than legacy carriers. This confirms the high degree of price competition in the industry. iv ACKNOWLEDGMENTS My sincere appreciation goes to my advisor, Dr. Siew Hoon Lim, for her guidance and advice provided throughout this research. I thank her for her patience and motivation, which helped me immensely during the progression of this study. My thanks also goes out to my committee members, Dr. Ryan Larsen and Dr. Alan Dybing, for their insightful comments and encouragement. I would like to extend my gratitude to the Upper Great Plains Transportation Institute for funding this research. I am grateful to Enrico Sassi, Director of the Graduate Center for Writers, for his graduate academic writing class and for the countless number of hours he spent outside the classroom coaching me. Finally, I would like to thank my parents for their support and my wife for the encouragement that she provided throughout this study. v

Trucks are critical in rural-economy market connectivity in where natural resource based goods are delivered to processors and consumer markets. The role of trucks in oil development is evident in the rapidly expanding fleet that operates within and serves western North Dakota. A fixed capacity public road system, has greatly increased large truck-passenger vehicle interaction in the region. The associated increasing crash risk is evident in recent trends (Figures). Seventy percent of fatal and serious injury crashes occur on rural non-interstate roads. Two critical aspects in minimizing potential crash risk associated with the interaction are education and enforcement. Education can be offered through public information releases and media campaigns. These campaigns can be used to create greater awareness of the risks and needs for defensive driving. Coupling this education with enforcement is essential in providing sustainable traffic safety programs (Shults et. al 2004, Houston an...

The Rural Transportation Safety and Security Center vision is to promote and enhance the region's transportation safety and security through research, education, and outreach in a partnership with stakeholders. It is a collaborative effort between Upper Great Plains Transportation Institute and the North Dakota Department of Transportation, with funding from the Federal Highway Administration. Transportation safety and security are critical issues for personal and freight mobility. Security issues are prominent given the large the border area, high-volume commercial traffic corridors, and limited security resources. Our initial challenge with security is to understand the risks and issues that are priorities in rural areas. The Rural Transportation Safety and Security Center will work with stakeholders to conduct research, education, and outreach that will enhance quality of life through safer and more secure rural transportation. This paper is an example of how the Center is fulfilling that goal. The Cooperative Research Program under the auspices of the American Association of State Highway and Transportation Officials has released a report, NCHRP Report 525, Volume 3 "Incorporating Security into the Transportation Planning Process." The research conducted for this authoritative treatment of the subject was completed in 2004. Since that time, a number of new programs, most notably in the federal government arena have been completed. It is the purpose of this paper is to supplement the information in the NCHRP report with relevant updated information. The information presented should provide a context in which the reader can continue to learn more in the specific areas of interest. This paper describes the initiatives of the U.S. Department of Homeland Security (DHS) at a fairly high level so that members of Metropolitan Planning Organizations (MPO) can gain an overview understanding of the direction that agency is taking. Similarly, the highway security programs of the U.S Department of Transportation, in conjunction with the DHS, are described. The paper then describes other programs on behalf of other agencies within the federal government, states, and urban areas that have been undertaken. TABLE OF CONTENTS 1. INTRODUCTION .

The Interstate Commerce Commission (ICC) was created by Congress in 1887 under the Interstate Commerce Act. The primary responsibilities of the ICC were to control competition and stabilize rates for a then monopolistic rail industry. The ICC's responsibilities were later extended to motor carrier, barge, and airline industries. In recent decades the ICC has undergone reform in its regulation of the transportation industry. The process of converting the transportation industry's highly regulated environment to a deregulated, competitive market, is the product of several legislatively enacted administrations and ICC members. As a new administration takes office, it is important to understand the evolution of the ICC and the administration's influence on ICC operations. Powers allowing the President and the Senate's Surface Transportation Subcommittee to approve nominations for the ICC provide the most visible opportunity for influencing the ICC's philosophy and actions, and thus the regulatory environment for the transportation industry.

North Dakota consistently experiences a relatively high level of crashes and injuries on rural roads, considering lane miles and vehicle miles traveled. Approximately 55% of the state"s travel, in vehiclemiles, takes place on rural roads. North Dakota fatal crash reports from 2003 to 2007 show that 89% of serious injuries, including fatal and disabling injuries, occurred on rural roads. The state continues to assess and deploy resources to reduce crashes and injuries on rural roads as outlined in work plans such as the Highway Safety Improvement Plan and the Highway Safety Plan. An important aspect of successfully pursuing a state and federal emphasis on rural road safety is to understand the effectiveness of individual and coordinated safety interventions. The overall goal of this project was to measure effectiveness for alternative levels of intervention designed to heighten awareness and safety on rural roads in a targeted corridor. A multi-county case study was designed to include sustained and multifaceted safety interventions. Two counties in North Dakota were selected to be included in a designated Traffic Safety Corridor where safety interventions would occur. Another county beyond the corridor was monitored as a control case. Metrics used to measure effectiveness were a multi-phase driver survey, direct seat belt observations which occurred pre-intervention, mid-intervention, and postintervention, and county-level crash/citation data. Overall, results of this research indicate that the project interventions that were implemented had little effect on overall seat belt use of the targeted counties.