Recent Submissions

  • Effects of Reading Text While Driving: A Driving Simulator Study

    Prevedouros, Panos; Miah, M. Mintu; Nathanail, Eftihia (2020-02)
    Although 47 US states make the use of a mobile phone while driving illegal, many people use their phone for texting and other tasks while driving. This research project summarized the large literature on distracted driving and compared major outcomes with those of our study. We focused on distraction due to reading text because this activity is most common. For this research project, we collected simulator observations of 203 professional taxi drivers (175 male, and 28 female) working at the same Honolulu taxi company, using the mid-range driving simulator VS500M by Virage. After a familiarization period, drivers were asked to read realistic text content relating to passenger pick up displayed on a 7-inch tablet affixed to the dashboard. The experimental scenario was simulated on a two-lane rural highway having a speed limit of 60 mph and medium traffic. Drivers needed to follow the lead vehicle under regular and text-reading conditions. The large sample size of this study provided a strong statistical base for driving distraction investigation on a driving simulator. The comparison between regular and text-reading conditions revealed that the drivers significantly increased their headway (20.7%), lane deviations (354%), total time of driving blind (352%), maximum duration of driving blind (87.6% per glance), driving blind incidents (170%), driving blind distance (337%) and significantly decreased lane change frequency (35.1%). There was no significant effect on braking aggressiveness while reading text. The outcomes indicate that driving performance degrades significantly by reading text while driving. Additional analysis revealed that important predictors for maximum driving blind time changes are sociodemographic characteristics, such as age and race, and past behavior attributes.
  • Operational Safety of Gravel Roads in Rural and Tribal Communities: Vulnerability to Structural Failures and GeoHazards

    Ibrahim, Ahmed; Sharma, Sunil; Kassem, Emad; Nielsen, Richard; Nasrin, Sabreena (2020-04-20)
    Of the 4.1 million miles of federal and state highways in the U.S., 2.2 million miles (or 54%) are unpaved, gravel roads. In the Pacific Northwest and Alaska, unpaved gravel roads provide critical transportation access, with some communities relying on just a single highway for access into and out of town. In such cases, these highways become a critical component of the infrastructure, and there is a need to ensure that safe access is always available to the communities. The Idaho highway database has been used to identify unpaved, gravel roads in Idaho that are critical for access to rural communities. Once identified, information regarding their existing condition has been used to assess their vulnerability and other impacts. The results of this study are considered an initial evaluation that relies on information that is readily available in the database. The project outcomes include a comprehensive literature review of unpaved roads including data produced from field visits. In addition, a questionnaire survey was sent to local jurisdictions authorities for investigating locations, reasons of road closures, and population size of the affected communities. Finally, 37 responses have been received by the research team indicating five rural communities that have experienced closures and isolation. The reasons for the closure of the unpaved roads were due to the lack of funding for snow removal, excessive dirt, unstable gravel roads, tornados, and heavy rains. The location of those communities was spread across the state of Idaho with corresponding populations range from 25 to 8,500 people.
  • DRONES FOR IMPROVING TRAFFIC SAFETY IN RITI COMMUNITIES IN WASHINGTON STATE

    Ban, Xuegang (Jeff); Abramson, Daniel; Zhang, Yiran (2020-04-04)
    Transportation and traffic safety is a primary concern in Rural, Isolated, Tribal, or Indigenous (RITI) communities in Washington (WA) State. Parallel to this, while emerging technologies (e.g., connected/autonomous vehicles, drones) have been developed and tested in addressing traffic safety issues, they are often not widely shared in RITI communities for various reasons. Compared with other technological advances, drone technologies have been rapidly improved and can be flexibly applied to multiple fields, including engineering, agriculture and disaster managements. The goal of this study is to explore and synthesize the opportunities, challenges and scenarios that drone technologies can assist to resolve traffic safety related issues and concerns in RITI communities. Through the outreach activities with the outer Pacific Coast in WA state, it is found that the principal concern within these communities are disaster management and mitigation since they are facing the threat of coastal erosion, earthquake and tsunami. Thus, the emergency management and hazard mitigation becomes the major way to further explore drone applications in the selected communities. To achieve this, we reviewed the current state of the drone technologies, conducted surveys from National Guard and coastal communities in WA, including City of Westport, South Beach Region, Grays Harbor County, Shoalwater Bay Tribe, and Quinault Indian Nation, to better understand their current needs, challenges and issues. Ultimately, recommendations of drone applications under specific scenarios are provided based upon the integration of drone technologies with community safety needs.
  • Enabling Data-Driven Transportation Safety Improvements in Rural Alaska

    Bennett, F. Lawrence; Metzgar, Jonathan B.; Perkins, Robert A. (2019-12)
    Safety improvements require funding. A clear need must be demonstrated to secure funding. For transportation safety, data, especially data about past crashes, is the usual method of demonstrating need. However, in rural locations, such data is often not available, or is not in a form amenable to use in funding applications. This research aids rural entities, often federally recognized tribes and small villages acquire data needed for funding applications. Two aspects of work product are the development of a traffic counting application for an iPad or similar device, and a review of the data requirements of the major transportation funding agencies. The traffic-counting app, UAF Traffic, demonstrated its ability to count traffic and turning movements for cars and trucks, as well as ATVs, snow machines, pedestrians, bicycles, and dog sleds. The review of the major agencies demonstrated that all the likely funders would accept qualitative data and Road Safety Audits. However, quantitative data, if it was available, was helpful.
  • Development of Landslide Warning System

    Riad, Beshoy; Zhang, Xiong (2019-11)
    Landslides cause approximately 25 to 50 deaths and US$1 - 2 billion worth of damage in the United States annually. They can be triggered by humans or by nature. It has been widely recognized that rainfall is one of the major causes of slope instability and failure. Slope remediation and stabilization efforts can be costly. An early warning system is a suitable alternative and can save human lives. In this project, an early warning system was developed for a 40-foot-high cut slope on the island of Hawaii. To achieve the objective, subsurface investigations were performed and undisturbed samples were collected. For the purpose of unsaturated soil testing, new testing apparatuses were developed by modifying the conventional oedometer and direct shear cells. The unsaturated soil was characterized using two separate approaches and, later, the results were discussed and compared. The slope site was instrumented for the measurement of suction, water content, displacement, and precipitation. The collected climatic data along with the calibrated hydraulic parameters were used to build an infiltration-evapotranspiration numerical model. The model estimations were compared with the field measurements and showed good agreement. The verified model was used to determine the pore-water pressure distribution during and after a 500-years return storm. Later, the pore-water pressure distribution was transferred to a slope stability software and used to study the slope stability during and after the storm. Based on a 2D slope stability analysis, the slope can survive the 500-year storm with a factor of safety of 1.20. Instrument threshold values were established for water content sensors and tensiometers using a traffic-light-based trigger criterion.
  • Development of a Computer Vision-Based Three-Dimensional Reconstruction Method for Volume-Change Measurement of Unsaturated Soils during Triaxial Testing

    Zhang, Xiong; Xia, Xiaolong (2019-10)
    Problems associated with unsaturated soils are ubiquitous in the U.S., where expansive and collapsible soils are some of the most widely distributed and costly geologic hazards. Solving these widespread geohazards requires a fundamental understanding of the constitutive behavior of unsaturated soils. In the past six decades, the suction-controlled triaxial test has been established as a standard approach to characterizing constitutive behavior for unsaturated soils. However, this type of test requires costly test equipment and time-consuming testing processes. To overcome these limitations, a photogrammetry-based method has been developed recently to measure the global and localized volume-changes of unsaturated soils during triaxial test. However, this method relies on software to detect coded targets, which often requires tedious manual correction of incorrectly coded target detection information. To address the limitation of the photogrammetry-based method, this study developed a photogrammetric computer vision-based approach for automatic target recognition and 3D reconstruction for volume-changes measurement of unsaturated soils in triaxial tests. Deep learning method was used to improve the accuracy and efficiency of coded target recognition. A photogrammetric computer vision method and ray tracing technique were then developed and validated to reconstruct the three-dimensional models of soil specimen.
  • Laboratory and Field Evaluation of Modified Asphalt Binders and Mixes for Alaskan Pavements

    Liu, Jenny; Liu, Jun (2019-08)
    In order to properly characterize modified asphalt binders and mixes for Alaskan pavements, this study evaluated properties of 13 asphalt binders typically used in Alaska from three different suppliers, and 10 hot mix asphalt (HMA) mixtures which were either produced in the lab or collected from existing paving projects in Alaska. Various binder and mixture engineering properties were determined, including true high binder grades, complex modulus (G*), and phase angle (δ) at high performance temperatures, multiple stress creep recovery rate and compliance, bending beam rheometer stiffness and m-value, Glover-Rowe parameter, ΔT, rheological index, and crossover frequency for binders, and rut depth, critical strain energy release rate (Jc), Indirect tensile (IDT) creep stiffness and strength for mixtures. Binder cracking temperatures were determined using asphalt binder cracking device. Mixture cracking temperatures were determined with IDT creep compliance and strength data. It was found that rutting and cracking resistances of the mixtures with highly modified binders were better than the mixture with unmodified asphalt binder (PG 52-28). Future recommendations for highly modified asphalt binders applications and research were provided based on laboratory testing results and field survey evaluation.
  • Reaching Out to Tribal Communities: Lessons Learned and Approaches to Consider

    Awwad-Rafferty, Rula; Chang, Kevin; Brown, Helen (2019-12-31)
    When transportation safety decision-making is desired, the involvement and engagement with a community is essential. A streamlined delivery of a project or program is more likely to occur when active dialogue and an exchange of ideas occurs in advance and occurs frequently. This is particularly important in tribal communities, who value sustained relationships and represent the focus population of this study. The research team, on six separate occasions, met with local and regional tribal leaders to explore and discuss transportation safety needs within and outside tribal communities, as well as discern the recommended approaches to foster ongoing dialogue about these needs. In all cases these discussions closely correlated with existing research studies or activities; transportation safety and equity is not seen as separate from other tribal foci and community needs. Specific recommendations to consider, in no particular order, included the following: invest respectfully enough time for people to talk; tribes think long-term and consider the impact of any decision from a long-term viewpoint so an iterative process and re-sharing of ideas is critical; the power of decision is in the hands of the tribe and its members; do not lump tribes together as each tribe is sovereign and unique and every community should be expected to think differently; all tribes are unique as is the environmental and social context; to disseminate information widely and iteratively, do so when there is a large group or event; be sure to understand the Tribal governance, decision making, and organizational structure; know who is the tribal Chairman or Chairwoman; and develop an emic and etic understanding of the community.
  • Highly Abrasion-resistant and Long-lasting Concrete

    Liu, Jenny; Murph, Diane (2019-08)
    Studded tire usage in Alaska contributes to rutting damage on pavements resulting in high maintenance costs and safety issues. In this study binary, ternary, and quaternary highly-abrasion resistant concrete mix designs, using supplementary cementitious materials (SCMs), were developed. The fresh, mechanical and durability properties of these mix designs were then tested to determine an optimum highly-abrasion resistant concrete mix that could be placed in cold climates to reduce rutting damage. SCMs used included silica fume, ground granulated blast furnace slag, and type F fly ash. Tests conducted measured workability, air content, drying shrinkage, compressive strength, flexural strength, and chloride ion permeability. Resistance to freeze-thaw cycles, scaling due to deicers, and abrasion resistance were also measured. A survey and literature review on concrete pavement practices in Alaska and other cold climates was also conducted. A preliminary construction cost analysis comparing the concrete mix designs developed was also completed.
  • A Bio-Wicking System to Prevent Frost Heave in Alaskan Pavements: Phase II Implementation

    Galinmoghadan, Javad; Zhang, Xiong; Lin, Chang (2019-11)
    Water within pavement layers is the major cause of pavement deterioration. High water content results in significant reduction in soil’s resilient behavior and an increase in permanent deformation. Especially in cold regions, frost heave and thaw weakening cause extensive damage to roads and airfields. Conventional drainage systems can only drain gravity water not capillary water. Both preliminary lab and field tests have proven the drainage efficiency of a newly developed H2Ri geotextile with wicking fabrics. In this report, continuous research was conducted to verify the effectiveness of the wicking fabric in mitigating frost boil issues in Alaskan pavemnets. Two test sections were selected at two low volume roads on the campus of the University of Alaska Fairbanks. Soil moisture and temperature sensors were installed within the road embankments. The monitored data was used to analyze the soil migrations and evaluate the drainage performance of the wicking fabric. Preliminary monitoring results showed that the wicking fabric was effective in mitigating the frost boil problem.
  • Use of Cellular Concrete for Air Convection Embankment to Protect Permafrost Foundations in Cold Regions: Feasibility Study

    Liu, Jenny; Wu, Hanli (2019-08-15)
    The air convection embankment (ACE) is a technique used to protect permafrost from thawing in road construction in cold regions. However, the desired materials needed for ACE are not readily available, which prevents its extensive use in Alaska. To overcome the limitation of traditional ACE, and further improve the cooling effect of ACE, this study investigated the feasibility of using cellular concrete as an alternative material for ACE in cold regions. The heat transfer patterns of the cellular concrete ACE, the crushed-rock ACE, and the sand/gravel embankment were studied using the numerical simulation. The results of the present study show that the cooling performance of both cellular concrete ACE and crushed-rock ACE are superior to the traditional sand/gravel embankment. The cellular concrete ACE has better heat insulation property in the summer, and the crushed-rock ACE has stronger natural convection in winter. For the annual cooling efficiency of the two different ACE techniques, the proposed cellular concrete ACE has a better cooling effect on the foundation soil than the crushed-rock ACE. These results indicate that the thermal conductivity and specific heat capacity of construction materials have significant impacts on the performance of the ACE.
  • The Impact of Snowfall on Airport Operations and Delays

    Lee, Jukwan; Yan, Jia (2019-03-31)
    Flight delays or cancelations due to snowfall are a costly inconvenience, not only to airports but also to airlines, passengers and society as a whole. However, no quantitative research has ever been done to provide an analytical explanation about the issue. Though being a reliable alternative to melt snow on the runway and mitigate flight delays, the Heated Pavement System is not adopted in any US airports because of concerns over the initial investments and maintenance costs being higher than the economic loss from delays during unpredictable snowfall days. Combining weather and domestic flight data in Boston and Los Angeles regions, we analyze the benefits and costs associated with installing the Heated Pavement System. Using two advanced econometric methods, the Difference in Difference in Difference (DDD) and the nearest neighbor matching, we first develop a Delay Analysis model to evaluate the exact effect of snowfall on flight delays, and then we calculate the delay costs. Based on the empirical findings, we conduct cost-benefit analysis of installing HPS at the three airports in Boston area. Our results indicate that HPS is feasible for airports with a great number of flights and passengers, such as Boston Logan airport.
  • Examination of the Variability in Grout Test Results

    Ahn, Il-Sang; Friend, Trenton (2019-08-31)
    Keyway grouting is an operation that connects decked bulb-tee girders into one system. The quality of grout should be well maintained through reliable material test procedures. Due to the issues of discrepancy and variability, there have been several cases in which grout materials did not satisfy the compressive strength standard specified in the DOT&PF Standard Specifications for Highway Construction. This research examined the causes of such issues. Six factors – grout material, mix consistency, workmanship, initial curing/storing, curing method, and test equipment – were identified as the causes of strength variation. Their effects on strength variation were investigated by testing compressive strength of cube and cylinder specimens made from 5 grout materials that were used or considered to be used in DOT&PF projects. Grout material characteristics such as grout material and mix consistency have significant effect on strength variation. Workability and consolidation can be different from one material to another. Consequently, they affect compressive strength and its variation. Workmanship and test equipment were evaluated in this research to have moderate effect on strength variation. Especially, strength variation can increase when the workmanship factor combines with the grout material characteristics factor.
  • Pre-Stress Loss Due to Creep in Precast Concrete Decked Bulb-Tee Girders Under Cold Climate Conditions

    Vandermeer, Drew; Ahn, Il-Sang (2019-07-31)
    Accurate estimation of pre-stress losses is one of the important issues for the design of precast, pre-stressed concrete bridge girders. While this subject has been long studied by many researchers, studies on pre-stress losses in cold climates are minimal. In the present research, long-term pre-stress loss due to concrete creep was studied based on concrete creep test. Two concrete creep test frames were fabricated and placed indoors and outdoors. Concrete strains were measured by Demountable Mechanical Strain Gauge (DEMEC) from two 612 high-strength concrete cylinders in each frame. The concrete strains were collected for 11 months (7/26/2017 – 6/21/2018) after loading, and outdoor ambient temperature dropped below 0C between 100 and 250 days. Between 50 and 100 days, two curves from the two frames are similar in their patterns and values. After 100 days, the total strain from the indoor frame slowly increased reaching 1,600 and 1,700 after 250 days. However, the total strain from the outdoor frame varied between 1,000 and 1,500 and the averaged total strain was 1,300 after 250 days. In cold temperature, the occurrence of concrete creep and shrinkage was suppressed.
  • Developing an Interactive Baseline Data Platform for Visualizing and Analyzing Rural Crash Characteristics in RITI Communities

    Zhang, Guohui; Prevedouros, Panos; Ma, David T.; Yu, Hao; Li, Zhenning; Yuan, Runze (2019-10-01)
    This project focused on developing an interactive baseline crash data platform, termed as Rural Crash Visualization Tool System (RCVTS), to visualize and analyze rural crash characteristics in RITI communities. More than 975 thousand crash records were collected in the state of Alaska, Idaho, and Washington, from 2010 to 2016. Data fusion is applied to unify the collected data. In the proposed RCVTS platform, three main functions are defined: crash data visualization, data analysis, and data retrieval. Crash data visualization includes an on-street map based crash location tool and a graphic query tool. Data analysis involves a number of visualization approaches, including static charts— i.e., the scatter chart—the line chart, the area chart, the bar chart, and interactive graph— i.e., the sunburst chart. Users are allowed to generate customized analytical graphs by specifying the parameters and scale. The three types of authorized users are defined to download crash information in the data retrieval section following corresponding limitations. The proposed RCVTS was illustrated using a sample case with crash records of the State of Alaska. It showed that the proposed RCVTS functions well. Recommendations on future research are provided as well.
  • Developing a Data-Driven Safety Assessment Framework for RITI Communities in Washington State

    Wang, Yinhai; Sun, Wei; Yang, Hao; Gottsacker, Christopher; Ricord, Sam; Yin, Shuyi (2019-10-03)
    In the history of this country, rural, isolated, indigenous, and tribal (RITI) communities were commonly overlooked with regards to social infrastructure and support. This issue is evident in the development of the transportation networks of these areas and the distinct lack of road safety in these types of communities. RITI communities carry a significantly disproportionate amount of traffic collisions and fatalities compared to urban areas. In order to improve the traffic safety conditions of the RITI communities in Washington State, it is necessary to build a traffic safety management system. A baseline data platform was developed by integrating the collected safety related data for the RITI communities in Washington State in the Year 1 Center for Safety Equity in Transportation (CSET) project. Besides the baseline data, the traffic safety management also requires the safety assessment framework, which is the corner stone of the traffic safety management system. Therefore, this project aims to develop a data-driven safety assessment framework to enable an effective roadway safety management system and improve the traffic safety conditions for RITI communities. The framework is based on an effective and efficient database management system for traffic and crash-related data of the RITI communities. In addition, in order to assist transportation agencies in practices such as the identification of high-risk roadway segments, the developed database management system has powerful visualization functions. Besides the database management and visualization platform, this project also develops roadway safety performance indices and traffic safety assessment methods in the safety assessment framework. This project also provides guidance on how to utilize these safety performance indices and results of safety assessment methods for visualization and analysis.
  • A Novel Systematic Strategy Towards Air-Purifying, Corrosion Resistant and Self-Healing Concrete Infrastructure

    Yang, Zhengxian (2019-09-15)
    Transportation causes major emissions of harmful gases (NOx, CO, VOCs). These pollutants also travel long distances to produce secondary pollution such as acid rain. The most popularly used photocatalytic cementitious composites based on TiO2 achieve the air purification function under ultraviolet sunlight, significantly impeding a broader application of photocatalytic cementitious composites. This study focused on developing an environmentally friendly and durable cementitious system based on the multifunctional photocatalytic Graphitic carbon nitride (g-C3N4). The photocatalytic cementitious composites (PCC) were prepared in three manners: (1) incorporating g-C3N4 nanosheets (CNNs) in cement at three mixing dosages (0.5%, 1% and 2% by weight of cement), (2) applying CNNs at various concentration levels as the coating on recycled asphalt pavement aggregate, (3) applying CCNs s with vinyl chloride/vinyl ester/ethylene copolymer (as a binder) as the coating on cement mortar. The photocatalytic performance and durability of the newly developed cementitious composites were evaluated systematically and the results showed that the PCC hold marked efficiency in terms of NOx removal and self-cleaning when the CNNs were applied in a proper way. The obtained knowledge sheds light on a future perspective of developing a novel systematic strategy towards air-purifying, corrosion resistant, and self-healing concrete infrastructure.
  • Cost-Effective Use of Sustainable Cementitious Materials as Reactive Filter Media (Phase I)

    Li, Wenbing; Shi, Xianming (2019-08-31)
    This report presents a laboratory study on the use of nano SiO2 as modifier in crushed fines recycled concrete (CFRCs), coupled with thermal treatment, with the goal of fabricating a sustainable reactive medium to capture the chloride anions in deicer-laden stormwater runoff. A uniform design (UD) scheme was employed for the statistical design of experiments. Predictive models were developed based on the experimental data to quantify the influence of each design parameter on the effectiveness of removing Cl- ions from simulated stormwater. The models were verified, and then employed for predictions. Finally, the samples of different CFRCs modified by nano SiO2 and heating regimes were prepared under the optimal parameters identified via the Response Surface Methodology (RSM). The optimal processing of CRFCs include the use of admixing nano SiO2 at 0.3% (by mass), then heating the material at 525oC for 3h. The structure and properties of these CFRCs materials were characterized by XRD, FTIR, BET, SEM and EDS. These advanced characterization tools revealed that the modified CFRCs achieved great potential to chemically bind chloride anions. This work is expected to produce substantial benefits for highway agencies and other stakeholders of deicer stormwater runoff, through enhanced understanding of the efficacy and appropriateness of cementitious filter media in passive reactive systems for decreasing contaminant loading in stormwater runoff. The use of CRFCs as a low-cost sorbent will be economically attractive and environmentally sustainable, diverting them from waste stream and landfill and towards sustainable stormwater management.
  • Numerical Simulation of Snow Deposition Around living Snow Fences

    Petrie, John; Zhang, Kun; Shehata, Mahmoud (2019-09-13)
    In this study, computational fluid dynamics (CFD) was used to investigate the air flow around porous snow fences to gain insight into snow transport and deposition in the vicinity of fences. Numerical simulations were performed to validate the CFD approach using experimental data from a wind tunnel study. Subsequent simulations were used to test the use of a porosity model to represent fence geometry and determine the effect of fence spacing for fences comprised of multiple rows. The results demonstrate that CFD simulations can reproduce the aerodynamics around porous fences. Additionally, the flow field generated with a porosity model is in close agreement with that from a model with explicit representation of fence porosity. Simulations of fences comprised of two rows spaced at various distances demonstrate that when the row spacing is small the fence behaves as a single row.
  • Mapping the Wolverine Way: Identifying Conservation Corridors and Transboundary Linkages in the Canadian Crown of the Continent Region

    Clevenger, Anthony P. (2019-09-13)
    The Canadian Crown of the Continent (CCoC) is one of three zones where wolverines can move between Canada and the US, providing the last links for recruitment and ultimately gene flow to the highly fragmented population in the US Rocky Mountains. However, a combination of rapidly expanding logging, energy development and motorized recreation, along with a growing road network, threatens to fragment and diminish connections in this critical transboundary linkage between the US and Canada. This report summarizes a project to complete a 3-year sampling effort in the CCoC, which in turn completed a larger 6-year effort over a vast area of the central and southern Canadian Rockies. In 2016, the research team surveyed the last unsampled portion of the Alberta Rockies (south of Kananaskis Country to Highway 3) in addition to a substantial portion of the East Kootenay region of the British Columbia Rockies (BC; >9000 km2). This follow-up effort allowed the team to complete an entire ecoregion-wide wolverine survey in the Canadian Rockies ecoregion, from the US-Canadian border north to Banff and Yoho National Parks. From this data, researchers created density estimates and occupancy models of wolverine distribution and its multiple landscape stressors across an extensive and complex region of the Great Northern Landscape. The report summarizes research findings and makes recommendations regarding management strategies.

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