Simulation of Shipping Size Effects for Transportationand Oder Quantity in a Supply Chain

This paper investigated the interaction effects between inventory and transportation strategies in the logistics network. Demand volumes and shipping sizes were simulated as part of a new conceptual model using a discrete event simulation by minimizing the total logistics cost in the supply chain. The experiments indicate that the full truckload scenario leads to cost efficiency and the larger demand size results in smaller cost per unit based on economies of scale. Considering the interaction effects, demand size has a greater impact on cost reduction than shipping size. The total logistics cost in the system is dependent on replenishment rate and flow rates from the higher to the lower echelon. High inventory cost is the result of a fast replenishment rate and frequent orders, while shipping cost is dependent on the flow rates in a process and total travelling time or total travelling distance. Shipping size also has an impact on the level of service and the total cost along with effective order variability.

Productivity Growth in the Transportation Industries in the United States: An Application of the DEA Malmquist Productivity Index

This study reviews productivity growth in the five major transportation industries in the United States (airline, truck, rail, pipeline, and water) and the pooled transportation industry from 2004 to 2011. We measure the average productivity for these eight years by state in each transportation industry and the annual average productivity by transportation industry. The major findings are that the U.S. transportation industry shows strong and positive productivity growth except that in the years of the global financial crisis in 2007, 2008, and 2010, and among the five transportation industries, the rail and water sectors show the highest productivity growth in 2011.

Low-Clearance Truck’s Vertical Requirements at Roundabouts

While roundabouts have already been proven to be an effective intersection treatment, there are many instances where low-clearance vehicles have problems using roundabouts. Low-clearance vehicles, such as lowboy trailer trucks, have problems, damaging the curbs and truck aprons at roundabouts when there is not sufficient ground clearance. This area has been generally neglected by designers and U.S. states. The latest roundabout manual has guidelines available to design various features of the roundabouts, but they are not specific for low-clearance vehicles. While some previous studies have identified roundabout locations with ground-clearance problems for lowboy trailers that have truck-apron heights that are greater than three inches, no published information is available about truck-apron heights based on three-dimensional analyses. This study addresses the ground-clearance problems for low-clearance vehicles at roundabouts by proposing a procedure where truck-apron heights, truck-apron slope, circulatory roadway slope, and approach roadway slope are analyzed to determine the optimum design measurements for a roundabout’s vertical profile in order to accommodate low-clearance vehicles without terrain conflict. The study procedure was demonstrated on standard single-lane roundabouts and double-lane roundabouts designed according to latest roundabout guide, and recommendations were provided for truck-apron heights and the grade for various features of the roundabouts. This research can guide transportation planners and decision makers when determining the optimum roundabout vertical-profile design when low-clearance vehicles are expected. The study uses TORUS software to design roundabouts, and the AUTOTURN and AUTOTURN Pro 3D software for generating two-dimensional and three-dimensional vehicle simulations as well as for conducting three-dimensional vehicle-clearance analysis.

Forecasting Oil Production in North Dakota Using the Seasonal Autoregressive Integrated Moving Average (S-ARIMA)

North Dakota’s oil production has been rapidly increasing during the past several years. The state’s oil production in March 2013 even increased to more than twice the quantity produced in March 2011, and the estimated Bakken Formation reserves were reported very large compared with those of the United Arab Emirates. It eventually makes a question to us of how much oil will be able to be actually extracted with currently available technologies. To answer this question, this paper forecasts future oil development trend in North Dakota using the Seasonal Autoregressive Integrated Moving Average (S-ARIMA) model. Nonstationarity derived from a stochastic trend and the abrupt structural change of oil industry was a big potential problem, but through the Quandt Likelihood Ratio test, we found break points, which allowed us to select a model fitting period suitable for the S-ARIMA method to provide accurate statistical inference for the historical period. The seven major oil producing counties were investigated to determine whether the current oil boom was consistent across all oil fields in North Dakota. Empirical estimates show that North Dakota’s oil production will be more than double in the next five years. What we can predict with great certainty is that North Dakota’s influence over domestic and global oil supply systems will increase in the near future, especially over the next five to six years. This is good news for those who are concerned about domestic energy security in the USA.

Roundabout’s Impact on Nearby Businesses

The objective of this study is to determine if installation of roundabouts in a business area or on business corridors can be good for the businesses as well as improve the traffic flow in that area. This objective is achieved by emphasizing on roundabouts located in Kansas cities, particularly Topeka, Kansas. The study concentrates on conducting survey of businesses around the roundabout corridors in different places in the US including Topeka (Kansas), Junction City (Kansas), Newton (Kansas), and Carmel (Indiana). The survey results indicated a positive impact of roundabouts on businesses and traffic movement. Further, as there is no before and after corridor data available for making definite conclusions, a business corridor in Topeka, Kansas is simulated using both SIDRA and VISSIM software to evaluate the impacts of converting several traditional intersections in the corridor to roundabouts. The results from the simulation tasks have showed substantial reductions in vehicle delay and queuing for most of the traffic movements. Therefore, it was concluded that roundabouts on businesses corridor have a positive impact on traffic flows and business.

High-Risk Rural Road Safety Study and Determining the Crash-Reduction Factors for High-Risk Rural-Road Usage

More than 32,000 motorists are killed on U.S. roads and streets annually, and approximately 54% of the accidents occur on rural roads. In an attempt to address and reduce these fatalities, the current transportation act, the Safe, Accountable, Flexible, Efficient Transportation Equality Act: A Legacy for Users (SAFETY-LU), elevated the Highway Safety Improvement Program (HSIP) to a core program and included a $90,000,000 High-Risk Rural Road Program (HRRRP) to address and significantly reduce traffic fatalities and incapacitating injuries on rural major or minor collectors, and/or rural local roads. While there were many challenges to properly implement the HRRRP in counties, this study provided important information that was needed to identify the predominant crash types on HRRRP-eligible roads and compiled a list of countermeasures for the predominant crash types that were identified on Kansas’ high-risk rural roads. For the gathered countermeasures, crash reduction factors (CRFs) were also provided from the literature review, and their values were validated by conducting interviews with Kansas county engineers/officials. This study provided valuable information for the county engineers and local government officials while they worked on improving the safety of high-risk rural roads using HRRRP funds.

Speed Reduction Mitigation Strategies on Rural Highways at Two-Way Stop Control Intersections and Curves

Studies conducted on crashes at rural intersections of state highways and local roads/streets with two-way stop control have proved that the problem was likely poor judgment by the stopped driver on the minor approach of the speed of an oncoming vehicle and/or safe gap in traffic on the major highway. Several mitigating strategies have been suggested and studied in various studies to improve safety at the two-way stop control rural intersections and at other rural highway segments. There are also several low-cost techniques used, mostly in foreign countries, to slow drivers on major highways as they enter small towns and villages, e.g., narrowing pavement lines, establishing visual gateways, etc. Lowered speeds would decrease crash severity. In this study, four strategies including solar speed display units, mobile speed trailers, optical speed bars, and colored pavement were tested and assessed in some locations in Kansas. The results of this research indicate that both solar speed display units and mobile speed trailers are effective in speed reduction at the desired points, but optical speed bars and colored pavements do not yield reliable results. Additional studies and longer term studies, should be conducted.

Reshaping Tribal Road Network Using Public Information

The area with the fastest growing Native American population in North Dakota is the Fort Berthold Reservation. State and federal road information available to the public is not identical in terms of the number of physical road segments or in the attribute information provided for the road network. In this study we develop: 1) a navigable road network achieved by improving connectivity among road segments, updating road information, and making a comprehensive network;and 2) a standard process for integrating the state and federal local road information. The standard process broadly consists of three Parts: 1) combining road segments from each source;2) providing legitimacy to snapping distance;and 3) performing a snapping based on the result of Part 2 to connect those road segments, which remained unconnected from Part 1. The findings show that data on local roads on the Fort Berthold Reservation from the two different sources are joined through the standard process, and the process saves considerable time and resources required for fixing the road network. The standard process that has been developed here can be applied to a variety of other Indian road information integration projects to join not only physical road segments, but also plural attribute information. The process will also be useful for a variety of other projects integrating road information, which is available to the public, in order to overcome financial and time limitations.

Application of Signal Detection Theory to Ascertain Driving Risk and Mitigation in a Flooded Urban Area

Signal Detection Theory （SDT） offers an unparalleled deterministic set of decision variables necessary to formulate applied risks in transportation. SDT has distinct advantages over basic prediction models since the latter may not represent an entirely accurate analysis. Thresholds based on elements of stimulus （signal and noise） and response for： a Type I discrimination of response variable where decision outcomes and rates are computed for metacognition to discriminate a Type II of decision outcomes was set. We also adapted the classical Dijkstra＇s shortest path algorithm within a GIS environment using Avenue programming. Contours derived from LiDARwere used to set flood levels while satellite imagery corresponding to Red River of the North inundated （signal） areas were acquired amongst other spatial datasets. The signal information was further dichotomized using a binary yes-no model. Origin and destination points constrained within Fargo-Morehead were generated using a random point generator. From these points, trips were generated with some connected segments traversing through flooded areas. By analyzing False Alarm Rate （FAR） and Corrected Rejection （CRR） computation, we found out that, when Hit Rate （HR） and FAR are both low then there was an increased corresponding sensitivity. At 30-35 ft flood level, the values for FAR and HR was 0.97 and 0.91 respectively.When FAR〉HR, lower set flood levels offered numerous route choices. Corresponding routes with associated impedance can be classified for risk-averse drivers or risk-takers While the risk-averse avoid risky and unfavorable routes, the risk-taker optimizes at an adjustment factor of ω = 0.1 or ω = 0.2. An idealistic stage is achieved for a conservative, co, equal to 0.4 or 0.5, which indicates maximum achievement in terms of time gain and safety simultaneously. At ω = 0.0 the prevailing conditions can be considered unrealistic since they incorporate areas considered impassable with absolute resistance like segments with a ＂Road Closed＂ or ＂Detour＂ sign. The applicability of our approach can be used to design multi-level and multi-modal transportation systems involving risk.

Integrating Roundabouts with Freight Roadway Networks

The demand for freight transportation in the United States has grown rapidly in the past couple of decades;the rate at which the highway capacity is growing is not able to meet the freight-trans- portation needs, resulting in congestion and delay, ultimately affecting the users and the public with increased prices for the goods delivered, unreliable delivery times, and air-pollution concerns. Freight bottlenecks are a major cause of recurring congestion which accounts for about 40% of total vehicle hours of delay in the United States. Intersections for urban freight-roadway networks are one of the major freight bottlenecks and are considered to be a significant contributor for congestion and delay. Improving the efficiency at urban intersections with high truck traffic can address the freight-traffic congestion, leading to optimized goods movement as well as decreased delays, congestion, and emissions, thus enhancing the air quality in and around the communities. With the roundabout intersection control being proven as a safe, operationally efficient, and environment-friendly control treatment, a greater use of roundabouts with urban freight- roadway networks and their feasibility is analyzed in this study. The control for most urban intersections is a signalized treatment;a performance analysis is conducted for selected signalized intersections in urban freight-roadway networks, comparing the intersections by adapting a roundabout control theoretically using SIDRA (signalized and un-signalized intersection design and research aid) Intersection software. Various parameters, such as the intersection’s level of service, the effective intersection capacity, the average control delay, vehicular emissions [carbon dioxide (CO2), hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NOx)], the intersection’s annual delay, and the intersection’s annual cost, are selected for comparison.

Anisotropic Damage Mechanics Modeling of Concrete under Biaxial Fatigue Loading

An anisotropic damage mechanics model is presented to describe the behavior and failure of concrete under biaxial fatigue loading. Utilizing the approach of bounding surfaces, the limit surface becomes a special case when the number of loading cycles is set to one. By increasing the number of loading cycles, the strength of concrete gradually decreases and the limit surface is allowed to contract and form new curves representing residual strengths. The magnitude of loading, load range, and the load path are known to influence the fatigue life and hence are addressed in this formulation. In this paper, a strength softening function is proposed in order to address the reduction in the strength of concrete due to fatigue. Separate softening functions are also proposed to account for the deformation characteristics in concrete under cyclic loading. Numerical simulations predicted by the model in both uniaxial and biaxial stress paths show a good correlation with the experimental data available in the literature.

Study of pedestrian hybrid beacon's effectiveness for motorists at midblock pedestrian crossings

Pedestrian signals, particularly at signalized, midblock crossings, delay drivers, which is termed ＂unnecessary delay＂ in this study. A pedestrian hybrid beacon was proven to be effective in decreasing this unnecessary delay to the drivers at midblock pedestrian crossings when compared to standard signalized midblock crossings. Two pedestrian hybrid beacons were installed at midblock pedestrian crossings in Lawrence, Kansas. A study was conducted at these two locations to determine the effectiveness of the pedestrian hybrid beacon in decreasing the unnecessary delay to drivers by comparing them with a signalized midblock on Massachusetts Street, Lawrence, Kansas. In addition to the delay measurements for drivers at pedestrian hybrid beacon and signalized treatment at midblock pedestrian crossings, other parameters such as driver compliance rate, pedestrian compliance rate, and other driver and pedestrian characteristics were also studied. Video cameras were used at these test locations and the effectiveness of the pedestrian hybrid beacon was analyzed from the video. A more than 90% reduction in delays was observed for the drivers at the pedestrian hybrid beacon at midblock crossings compared to the signalized crossing. Further, a better driver compliance rate was also recorded at the pedestrian hybrid beacon. Information about reductions in unnecessary delay to drivers and improvements to driver and pedestrian compliance rates from the use of pedestrian hybrid beacons would be useful to engineers, decision makers, and researchers to determine an optimum treatment at desired pedestrian crossings.