Objectives: Motor vehicle crash fatality rates have been consistently higher in rural areas than in urban areas. However, the explanations for these differences are less clear. In this study the decomposition method was used to explore the factors associated with increased fatal crash involvement rates in rural communities. Design: Using national databases, the fatal crash incidence density was decomposed into the product of three factors: the injury fatality rate, the crash injury rate, and the crash incidence density. Results: As expected, the fatal crash incidence density was more than two times higher in rural than in urban areas. This was driven primarily by the injury fatality rate, which was almost three times higher in rural areas. Conclusions: Further research should examine the relative roles of crash severity and the timely receipt of definitive medical care after a crash.

https://injuryprevention.bmj.com/content/injuryprev/11/1/24.full.pdf

Fatal motor vehicle crashes in rural and urban areas: decomposing rates into contributing factors

Past editions of the American Association of State Highway and Transportation Officials (AASHTO) Guide for Design of Pavement Structures have served well for several decades; nevertheless, many serious limitations exist for their continued use as the nation's primary pavement design procedures. Researchers are now incorporating the lat- est advances in pavement design into the new Mechanistic-Empirical Pavement Design Guide (MEPDG), developed under the National Cooperative Highway Research Program (NCHRP) 1-37A project and adopted and published by AASHTO. The MEPDG procedure offers several dramatic improvements over the current pavement design guide and presents a new paradigm in the way pavement design is performed. However, MEPDG is substantially more complex than the AASHTO Design Guide by considering the input parameters that influence pavement performance, including traffic, climate, pavement structure and material properties, and applying the principles of engineering mechanics to predict critical pavement responses. It requires significantly more input from the designer. Some of the required data are either not tracked previously or are stored in locations not familiar to designers, and many data sets need to be pre- processed for use in the MEPDG. As a result, tremendous research work has been conducted and still more challenges need to be tackled both in federal and state levels for the full implementation of MEPDG. This paper, for the first time, provides a comprehensive bird's eye view for the MEPDG procedure, including the evolvement of the design method- ology, an overview of the design philosophy and its components, the research conducted during the development, im- provement, and implementation phases, and the challenges remained and future developments directions. It is antici- pated that the efforts in this paper aid in enhancing the mechanistic-empirical based pavement design for future con- tinuous improvement to keep up with changes in trucking, materials, construction, design concepts, computers, and so on.

https://link.springer.com/content/pdf/10.1007/BF03325749.pdf

Mechanistic-empirical pavement design guide (MEPDG): a bird’s-eye view

Ad hoc networks can be used not only as data carriers for mobile devices but also as providers of a new class of services specific to ubiquitous computing environments. Building services in ad hoc networks, however, is challenging due to the rapidly changing operating contexts, which often lead to situations where a node hosting a certain service becomes unsuitable for hosting the service execution any longer. We propose a novel model of service provisioning in ad hoc networks based on the concept of context- aware migratory services. Unlike a regular service that executes always on the same node, a migratory service can migrate to different nodes in the network in order to accomplish its task. The migration is triggered by changes of the operating context, and it occurs transparently to the client application. We designed and implemented a framework for developing migratory services. We built TJam, a proof-of-concept migratory service that predicts traffic jams in a given region of a highway by using only car-to-car short-range wireless communication. The experimental results obtained over an ad hoc network of personal digital assistants (PDAs) show the effectiveness of our approach in the presence of frequent disconnections. We also present simulation results that demonstrate the benefits of migratory services in large-scale networks compared to a statically centralized approach.

/pdf/context-aware-migratory-services-in-ad-hoc-networks-535ni9rhxb.pdf

Context-Aware Migratory Services in Ad Hoc Networks

This research investigates the use of highresolution three-dimensional terrestrial laser scanners as tools to capture geometric range data of complex scenes for structural engineering applications. Laser scanning technology is continuously improving, with commonly available scanners now able to capture over 1,000,000 points per second with an accuracy of ∼0.1 mm. This research focuses on developing the foundation toward the use of laser scanning to structural engineering applications, including structural health monitoring, collapse assessment, and post-hazard response assessment. One of the keys to this work is to establish a process for extracting important information from raw laser-scanned data sets such as the location, orientation, and size of objects in a scene, and location of damaged regions on a structure. A methodology for processing range data to identify objects in the scene is presented. Previous work in this area has created an initial foundation of basic data processing steps. Existing algorithms, including sharp feature detection and segmentation are implemented and extended in this work. Additional steps to remove extraneous and outlying points are added. Object detection based on a predefined library is developed allowing generic description of objects. The algorithms are demonstrated on synthetic scenes as well as validated on range data collected from an experimental test specimen and a collapsed bridge. The accuracy of the object detection is presented, demonstrating the applicability of the methodology. These additional steps and modifications to existing algorithms are presented to advance the performance of data processing on laser scan range data sets for future application in structural engineering appli∗To whom correspondence should be addressed. E-mail: Jf.hajjar@neu.edu. cations such as robust determination of damage location and finite element modeling.

Data Processing of Point Clouds for Object Detection for Structural Engineering Applications

Globally, 1.3 billion on-road vehicles consume 79 quadrillion BTU of energy, mostly gasoline and diesel fuels, emit 5.7 gigatonnes of CO2, and emit other pollutants to which approximately 2...

https://www.tandfonline.com/doi/pdf/10.1080/10962247.2018.1454357

Trends in onroad transportation energy and emissions.

This report outlines the forensic investigation of the collapse of Bridge No. SN 019-5010 in DeKalb County, Illinois on August 19, 2008. The bridge consisted of three 42 feet precast prestressed concrete deck beams simply-supported by concrete pile caps with a timber pile foundation. Assessment based on site investigation, in situ readings, and analysis indicated that a geotechnical or superstructure failure may be ruled out. Samples of the oak timber piles were retrieved and tested under pure compression as well as combined compression and flexure. Laboratory testing results of these specimens were used to calibrate an analytical model of a full-scale single timber pile. The analytical model considered both symmetrical and unsymmetrical loading of the bridge. The results of the analytical model were used to determine the required live load to initiate collapse. The results of the investigation indicate that structural overload, leading to fracturing of the timber piles in combined compression and flexure, is the likely reason for the bridge failure.

https://rosap.ntl.bts.gov/view/dot/16718/dot_16718_DS1.pdf

Forensic collapse investigation of a concrete bridge with timber piers.

https://pilemedic.com/pdfs/Borello%20et%20al.%20--%20Timber%20Bridge%20Piles%20Under%20Eccentric%20Load%20.pdf

Experimental and analytical investigation of bridge timber piles under eccentric loads

The use of integral abutment bridges (IABs) is growing rapidly in the U.S., primarily because of lower maintenance costs compared to conventional bridges. However, current length and skew limitations employed by IDOT are not based on rigorous engineering analysis. To potentially expand the use of IABs in Illinois, the project team performed extensive 2-D and 3-D analyses to examine a wide range of IAB parameters in addition to length and skew. The numerical analyses yielded the following findings when the bridge structures were subjected to extreme thermal loading: (1) The presence of the backfill and development of full passive pressures against the abutment backwall have a negligible effect on the pile foundation performance. (2) The use of wingwalls that are parallel to the bridge deck (rather than parallel to the abutment backwall) has little effect on the abutment or pile foundation performance, and does not significantly reduce backfill settlement when the backfill is uncompacted. In addition, use of uncompacted backfill reduces the vertical support of the approach slab and results in greater stresses and moments in the approach slab. (3) Soil type (when the soil is reasonably competent) has only a secondary effect on the abutment and pile foundation performance. (4) Use of steel vs. concrete girders (within the limited number of girder types and sizes considered) also has only a secondary effect on the abutment and pile foundation performance. (5) Acceptable IAB length and skew combinations that induce stresses in the foundation piles that do not exceed the pile yield stress are summarized in the report. Several moment-reducing options are available to increase these limitations, including: (a) predrilling pile locations to 8 feet, (b) reducing pile embedment into the pile cap to 6 inches (creating a hinge at the pile/pile cap interface), and (c) incorporating a mechanical hinge such as that used by the Virginia DOT at the cold joint between the pile cap and the abutment. (6) Instrumenting and monitoring one or more IABs in Illinois is essential to validate the numerical modeling described in this report, and to potentially investigate the effectiveness of one or more moment-reducing options.

https://rosap.ntl.bts.gov/view/dot/38658/dot_38658_DS1.pdf

Modification of IDOT Integral Abutment Design Limitations and Details

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Forensic collapse investigation of a concrete bridge with timber piers.

Experimental and analytical investigation of bridge timber piles under eccentric loads

Modification of IDOT Integral Abutment Design Limitations and Details