Wyoming Department of Transportation

100 Years of Excellence

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Completed Projects for FY2009 (October 1, 2008 to September 30, 2009)


Paul McCarthy

Keith Haskins


FHWA-WY 09/01F (RS02207)

Snow Snake Performance

ABSTRACT:  A recent study, “Three-Dimensional Roughness Elements for Snow Retention” (FHWA-WY-06/04F) (Tabler 2006), demonstrated positive evidence for the effectiveness of Snow Snakes, a new type of snow fence suitable for use within the highway right-of-way. Snow Snakes are wire frames covered with a continuous extruded plastic fabric and aptly named for their reptilian appearance.  This study evaluates the effectiveness of using Snow Snakes as a viable means to reduce road ice formed by blowing snow originating within the highway right-of-way.  Snow drift depths and lengths were measured along transects intersecting various snow fence types and configuration; this data was used to calculate trapped snow volumes and water equivalents. During the December 31, 2007 to February 6, 2008 observation period, Snow Snakes trapped and prevented approximately 622 tons of snow from potentially interacting with the roadway surface to form slush and ice.  Due to insufficient field data, obtaining conclusive evidence of the effectiveness of using Snow Snakes as a viable means to reduce road ice formed by blowing snow originating within the highway right-of-way will require additional study.



Ernie Scott

Inter-Mountain Laboratories

FHWA-WY 09/02F (RS06206)

Teton Pass Avalanche Monitoring


ABSTRACT:  Highway snow avalanche forecasting programs typically rely on weather and field observations to make road closure and hazard evaluations. Recently, infrasonic avalanche monitoring technology has been developed for practical use near Teton Pass, WY to provide another tool for Wyoming State Highway 22 technicians in their operational forecasting and decision making. The technology detects low frequency sound waves produced by avalanches with automated near real-time processing provided to facilitate an alarm. Monitoring system operation provides information to confirm results from avalanche control work, notification of natural avalanche events, and verification of explosive detonations. The ability to monitor avalanche activity in poor visibility and confirm avalanche control work results are powerful tools for assessing highway avalanche hazard and has changed the way WYDOT operates in its mission to provide a safe and efficient transportation route.


Qiyue Dai

Rhonda Young, orcid.org/0000-0001-6745-5008

Steven Vander Giessen

University of Wyoming

FHWA-WY 09/03F (RS10206)

Evaluating Wildlife Sensing and Driver Warning System

ABSTRACT:  Collisions with wildlife are a serious concern on American highways. In Wyoming, the concern has prompted the Wyoming Department of Transportation to construct an experimental wildlife detection and driver warning system at Trapper’s Point, north of the town of Pinedale on US Highway 191. The focus of this thesis is two-fold: to develop a framework to determine whether the driver warning system is effective at modifying driver behavior and to develop a framework to determine whether the wildlife detection system reliably detects the presence wildlife on the roadside. Transportation agencies have attempted to solve the deer-vehicle collision problem with a wide variety of solutions. Published literature was reviewed to analyze the effectiveness of these solutions with a spotlight on other active, wildlife-detecting driver warning systems. The system at Trapper’s Point utilizes the Eagle Intrusion Detection System (EIDS), originally developed by Telonics, Inc for military applications. Seismic and passive infrared sensors are designed to detect the presence of wildlife and trigger the flashing lights atop six signs that read “DEER ON ROAD WHEN FLASHING”. Many difficulties with the wildlife detection system and data collection equipment were experienced during this study. This report describes these problems in detail and analyzes the system using three measures of effectiveness: accurate detection of wildlife, changes in driver behavior, and crash reduction.


 FHWA-WY 09/04F (RS04207)

Interstate 80 Freight Corridor Analysis




Rand Decker

Joshua Hewes, orcid.org/0000-0002-2098-4399

Scotts Merry

Perry Wood

InterAlpine Associates

 FHWA-WY 09/05F (RS05205)

Snow Supporting Structures

ABSTRACT: The 151 Avalanche, near Jackson, Wyoming has, historically, avalanched to the road below 1.5 to 2 times a year. U.S. 89/191 is four lanes and carries an estimated 8,000 vehicles per day in the winter months. The starting zone of the 151 Avalanche is 1,140 vertical feet above the roadway. With the adjacent development of the South Park areas of the Jackson Hole Valley, using explosives for avalanche control is unacceptable. As a consequence, this project has led to the design and configuration of a deployment of snow supporting structures that if implemented, would provide a more effective avalanche defense system. This has resulted in a unit structural and foundation design for seventy (70) snow supporting structures. The unit design will support a maximum 6.6' snowpack. The 70 structures, deployed with a separation of 50' longitudinally, will cover the dominant portions of the 151 Avalanche starting zone. Moreover, novel deployment configuration has been developed to also retain the visual characteristics of the starting zone as seen from the Jackson Hole valley floor. This factor critically into the National Environment Policy Act (NEPA) rule-making responsibilities of the USDA Bridger-Teton National Forest and their resulting favorable Decision Memo. The resulting design of a snow supporting structure is 12' long and 5.5' high, installed nearly perpendicular to the slope which is inclined at 35 degrees. A single structure weights 1,400 pounds, and the cost is estimated at $16,600 per structure; fabricated, transported and installed.


Khaled Ksaibati, Ph.D., P.E.,  orcid.org/0000-0002-9241-1792

Cheng Zhong 

Bart Evans

University of Wyoming

FHWA-WY 09/06F (RS01207)

Wyoming Rural Road Safety Program

ABSTRACT: SAFETEA-LU contains language indicating that State Department of Transportation’s (DOTs) will be required to address safety on local and rural roads. The Wyoming Local Technical Assistant Program (LTAP) coordinated an effort in cooperation with the Wyoming Department of Transportation (WYDOT) as well as Wyoming counties and cities to identify low cost safety improvements on high risk rural roads in Wyoming. In this project, safety techniques and methodologies were developed to identify and then rank high risk locations on these rural roads. This project is unique because of the high percentages of gravel roads at the local level in Wyoming. The evaluation procedure developed is based on historical crash records and field evaluations. Three Wyoming counties were included in the pilot study. The statewide implementation began in 2009. This report describes the findings and recommendations of this research study which is not only beneficial to Wyoming but also to those states interested in implementing a High Risk Rural Road (HRRR) Program.



Brooke R. Ullman

Nada D. Trout

Gerald L. Ullman

Texas Transportation Institute

 FHWA-WY09/07F (RS02208)

Messages for Truck Mounted Changeable Message Signs

ABSTRACT:  The use of truck-mounted changeable message signs (TMCMSs) for mobile operations is desirable for providing drivers with information to better prepare them for unexpected conditions. Traditionally, temporary traffic control for mobile operations has been limited to arrow panels and sometimes static warning messages mounted to the work vehicle. The use of warning signs in advance of the work operation is typically not practical due to the constant movement or stop-and-go nature of the work. TMCMSs can fill an information gap for these mobile operations and providing drivers with better information regarding both the operation and the expected actions based on the operation. Based on the findings of both a human factors laboratory study and field evaluations conducted during this research and basic message design principles, researchers have created a sampling of recommended messages for use on TMCMS during mobile operations. These messages are defined by the type of work, road type, and identified concerns being addressed by the message.


John P. Turner

University of Wyoming

FHWA-WY 09/10F (RS07209)

Improving Foundation Design in Rock Load Test

ABSTRACT:  This report describes the results of a bi-directional load test on a drilled shaft foundation in weak sandstone. The test was conducted in conjunction with construction of a new bridge at Burma Road Overpass on I-90 in Gillette, Wyoming. The purpose was to provide much needed information on side resistance and base resistance in weak sandstone of the Tertiary Wasatch Formation. Load test results are compared to design equations for both soil and rock. Design equations based on treating the weak sandstone as cohesionless soil provide close agreement with side resistance values measured by the load test. Design equations based on treating the sandstone as rock also provide reasonable agreement with the load test results, but comparisons were limited by the inability to obtain representative intact core samples suitable for measuring the uniaxial compressive strength of the sandstone. Unit base resistance  mobilized in the load test exceeds by a significant amount the value of unit base resistance predicted using AASHTO and FHWA design equations. The load-displacement response of the test shaft is analyzed by fitting to an analytical model, providing a practical tool for evaluation of trial designs to satisfy service limit states. Finally, results of the load test are used to illustrate the application of AASHTO LRFD methodology to design of drilled shafts for the bridge at Burma Road Overpass.


Completed Projects for FY2010 (October 1, 2009 to September 30, 2010)


Kim Basham

KB Engineering

FHWA-WY 10/01F (RS04206)

ASR Affected Concrete

ABSTRACT:  This research project was undertaken to evaluate the potential of using surface treatments including lithium nitrate, sodium tartrate, siloxanes, silane, and boiled linseed oil to mitigate or slow the rate of concrete deterioration associated with alkali-silica reaction (ASR). Significant amounts of concrete pavements, curbs and gutters, sidewalks, etc. across Wyoming suffer from ASR and related freeze/thaw damage. Any extension of the service life of concrete through remediation can result in significant cost savings to Wyoming Department of Transportation (WYDOT). Also, materials and pavement engineers need methods to evaluate damage and rates of deterioration to help assess the life cycle of ASR-affected concrete.  Specific objectives of this investigation were: 1) evaluate the effectiveness of applying various surface treatments to mitigate or slow down the deterioration rate associated with ASR, 2) evaluate the appropriateness of using the Damage Rating Index (DRI) and ultrasonic pulse velocity (UPV) methods for assessing concrete damage and determining the rate of deterioration caused by ASR.


Emily Ahern

Jay Puckett orcid.org/0000-0002-0834-7549

University of Wyoming

FHWA-WY 10/02F (RS01210)

Reduction of Wind Induced Vibrtions in High Mast Light Poles

ABSTRACT:  High-mast light poles are frequently used in areas where widespread illumination is required, such as along interstates and at major highway interchanges.  The structures' heights are large relative to their cross-sectional dimensions, and, consequently, they are flexible and sensitive to wind loading.  A number of failures of high-mast structures have occurred due to fatigue cracking.  These failures have been linked to buffering and vortex shedding loads.  The primary study objective is to characterize the dynamic effects of wind-induced vibrations on high-mast structures in Laramie, Wyoming, and to propose several retrofits that increase the aerodynamic dampening, thereby reducing vibrations. 


George Huntington

Khaled Ksaibati, Ph.D., P.E.,  orcid.org/0000-0002-9241-1792

University of Wyoming

 FHWA-WY 10/03F (RS06209)




Gravel Road Management


ABSTRACT:  This report establishes procedures for managing dirt and gravel roads, with a primary focus on smaller agencies, such as Wyoming counties, that must manage their roads with very limited resources. The report strives, first, to guide and assist smaller agencies by implementing asset and pavement management principles and, second, to encourage and facilitate the development of gravel roads management software. The overall effort required to implement a gravel roads management system (GRMS) for local agencies must be minimal. Data collection efforts must be limited and the analysis must be simple and transparent. The four basic steps are: assessment; inventory; cost and maintenance history, and condition monitoring.

This report is divided into three volumes. Volume 1 outlines the Background, Problem Statement, Objectives, Report Organization, Analytical Methods, and Summary and Conclusions. Volume 2: Implementation Guide is designed to assist local road and street departments with implementation or improvement of a gravel roads management system. It is written primarily for road managers tasked with acquiring the necessary information to develop an information systems process. Volume 3: Programming Guide is intended to assist programmers and database managers with programming the information needed to implement a gravel roads management system.


Jenna Buddemeyer

Rhonda Young, orcid.org/0000-0001-6745-5008

Vijay Sabawat

Emily Layton

University of Wyoming

FHWA-WY 10/04F (RS05207)

Variable Speed Limit System for Elk Mountain Corridor

ABSTRACT:  Determining an appropriate speed for the current conditions can be difficult for the driver. Equally difficult is for law enforcement agencies to enforce and cite someone going too fast for conditions. In many cases, drivers are cited for going too fast for conditions only after the accident has occurred. Variable speed limits (VSL) are one type of intelligent transportation system (ITS) that has shown promise for improving safety on roadways subject to adverse conditions. The purpose of this research was to lay the foundation for the new I-80 VSL system in southeastern Wyoming. During this phase of the research, surveys were sent out to all DOTs to see what VSLs have been implemented in the U.S. Driver speed behaviors during both “ideal” and “non-ideal” conditions were found and baseline speeds determined. Weather and speed data were analyzed to determine key variables and threshold values. To check how cars and trucks are reacting to the VSL system individual speed analysis was done. A draft version of control strategy was designed and a simulation was run to check for level of speed compliance. The final task was to determine how drivers are reacting to the new VSL system.


Rhonda Young, orcid.org/0000-0001-6745-5008

Edward Offei

Quiyue Dai

University of Wyoming

FHWA-WY 10/05F (RS06207)

ITS System to Reduce High Wind Truck Crashes

ABSTRACT:  The state of Wyoming has frequent severe wind conditions, particularly in the southeast corner of the state along Interstate 80 and Interstate 25. The high winds are problematic in many ways including, interfering with the performance of the transportation system, blowing vehicles off the road, or even overturning high profile trucks, which can cause economic losses and safety concerns for road users. The primary objectives of this research involve two parts: First, develop a statistical model that reveals the correlation between likelihood of overturning trucks and the weather conditions. Second, use the result of the statistical model to develop a data driven operation plan for Wyoming Department of Transportation (WYDOT) to use in the winter season at a hazardous high wind corridor to improve truck safety.


Burton Andreen

Cody Kalivoda

Khaled Ksaibati, Ph.D., P.E.,  orcid.org/0000-0002-9241-1792

University of Wyoming

FHWA-WY 10/06F (RS07210)

Road Profiler Measurements in Fore Slopes of Shoulders

ABSTRACT:  The Wyoming DOT has an interest in collecting automated data on pavement shoulders. Such data would include shoulder width, type, as well as slope. Pathway Services Inc. has been collecting Pavement Management Systems (PMS) data on roadways in Wyoming, and indicated they had the ability to measure the transverse profile of 10 to 20 feet from the white strip shoulder marking. Pathway Services has offered to provide measurements on test sections in Wyoming since they had not collected such data for any other states, so it was important to them to determine the limitations or potential of the system.  The test sections included seventy miles of Wyoming highways with shoulder widths varying from zero to ten feet in two foot increments. Vegetation observations were made by researchers from the Wyoming T2-LTAP Center on the same day when Pathway’s data was collected to ensure identical conditions. It was found that the section with no shoulder had the most vegetation and the most varied slope measurements. It was concluded that vegetation does affect the accuracy of the sensor and that the sensor could not read past the pavement taper. In addition, the manually collected slope measurements and the automated slope measurements were statistically different on most of the sections included in the experiment.


Tyler Robison

Jennifer Tanner

University of Wyoming

FHWA-WY 10/07F (RS04209)

Bridge Deck Evaluation Using Non-Destructive Test Methods

ABSTRACT:  The state of Wyoming has 13.1 million sq. ft of road bridges (FHWA 2009), and evaluations have become an important part of the Wyoming Department of Transportation’s (WYDOT) management of bridge repairs. Nondestructive testing (NDE) methods developed in the past 20 years may provide an efficient, standardized, and accurate method for evaluating bridge deck conditions. This report presents the results of an exploratory study performed on three bridge decks in Wyoming: the First Street Bridge in Casper, the Douglas I-25 Bridge, and the Remount Bridge on I-80. The goal is to develop a practical solution that WYDOT can implement. In particular, the solution should capitalize on safety, efficiency and accuracy. The author evaluated each bridge using standard WYDOT practices for chain dragging and half-cell potentials, along with newer technologies of impact echo, thermal imaging, and ground penetrating radar (GPR), which provides a comprehensive assessment of the NDE evaluation techniques. Cores removed from the bridges were compared to the results from the evaluation methods. Damage locations indicated by impact echo, thermal imaging, and GPR generally correlated well and factors are presented in this report. This research suggests that a Combination of impact echo with GPR testing provides the most accurate predictions of delamination, debonding, and active corrosion on bridge decks.


Completed Projects for FY2011 (October 1, 2010 to September 30, 2011)


Hall Sawyer orcid.org/0000-0002-3789-7558

Chad LeBeau

Western EcoSystems Technology

FHWA-WY 11/02F (RS01209)

 Mule Deer Crossing Structures in Nugget Canyon

ABSTRACT:  Wildlife-vehicle collisions pose a major safety concern to motorists and can be a significant source of mortality for wildlife. A 13-mile section of Highway 30 in southwest Wyoming has been especially problematic with an average of 130 mule deer killed each year

WYDOT installed at total of seven underpasses along this area. Through three years of monitoring the study documented 49,146 mule deer moving through the underpasses. Overall, the construction of seven underpasses and game-proof fencing reduced deer-vehicle collisions by 81 percent. The results suggest that underpasses, combined with game-proof fencing, can provide safe and effective movement corridors for mule deer and other wildlife species while improving highway safety for motorists.


Scott Koch

George Huntington

Khaled Ksaibati, Ph.D., P.E.,  orcid.org/0000-0002-9241-1792

University of Wyoming

FHWA-WY 11/03F (RS07207)

Reclaimed Asphalt Pavement

ABSTRACT:  The University of Wyoming’s LTAP Center conducted a study examining the performance of reclaimed, recycled asphalt pavement (RAP) on unpaved roads in three Wyoming counties.  Fifteen material and dust suppression treatment combinations were examined.  Materials included three RAP sources from Wyoming interstate millings and one milled cement-treated base (CTB) from Interstate 80.  Dust suppressants included calcium chloride flakes, magnesium chloride brine, and brines made from blends of magnesium chloride with either lignin sulfonate or a proprietary polymer. 



Completed Projects for FY2012 (October 1, 2011 to September 30, 2012)



Justin Terfehr

Khaled Ksaibati, Ph.D., P.E.,  orcid.org/0000-0002-9241-1792

University of Wyoming

FHWA-WY 12/02F (RS03211)

Evaluating Department of Transportation's Research Programs

ABSTRACT:  An effective research program within a transportation organization can be a valuable asset to accomplish the goals of the overall mission. Determining whether a research program is pursuing relevant research projects and obtaining results for the sponsoring organization has been a challenge in the past. This report will present a methodology for conducting an evaluation of a research program within a transportation agency. The methodology provides ten performance measures that are used to summarize the findings of the evaluation. These performance measures are quantifiable, meaning they are designed to place a score or value on the accomplishments of the research program which can then be used to make managerial decisions for the research program. The developed methodology was implemented for the Wyoming Department of Transportation’s Research Program to demonstrate how the methodology can be utilized. Specific recommendations and conclusions for the WYDOT Research Program are presented in the final chapter of this report. Final recommendations for implementing the methodology for any other agency looking to perform an evaluation of their research program are also presented in the final chapter of this report.


Burt Andreen

Khaled Ksaibati, Ph.D., P.E.,  orcid.org/0000-0002-9241-1792

University of Wyoming

 FHWA-WY 12/03F (RS08210)

Crash Trends and Severity in North Rocky Mtn Region

ABSTRACT:  Safety Management Systems are federally mandated in an effort to encourage states to develop strategic programs in order to mitigate severe crashes. In 2006, the Wyoming Department of Transportation (WYDOT) published the Wyoming Strategic Highway Safety Plan (SHSP). The plan outlined goals for the state and transportation areas of strategic emphasis. While the SHSP has proven successful in lowering crash rates, Wyoming is constantly plagued by one of the highest fatal crash rates in the region. In the northern Rocky Mountain region, The basis of this research centers on evaluating key differences between North Dakota and Wyoming to determine if there are policies, practices, and or physical differences that keep North Dakota’s fatal crash rate lower. This research investigates patrol enforcement differences, traffic safety laws, crash records, mileage records, vehicle records, and economic factors as possible sources of crash rate differences.


Completed Projects for FY2013 (October 1, 2012 to September 30, 2013)


Dane Hopkin

Ryan Kobbe

John P. Turner

University of Wyoming

FHWA-WY 13/01F (RS10211)

Criteria for WYDOT Culvert Selection Policy

ABSTRACT:  This report discusses geotechnical and material considerations for culvert design and selection. The purpose of this report is to present the Wyoming Department of Transportation with information in order to alter, improve, and incorporate changes to their standard road and bridge specifications. Research included in this study synthesizes AASHTO, ASTM, State DOT, and NCHRP literature among other technical documentation, as well as State DOT surveys that outline important considerations for culvert design. Additional areas of research discussed in this report include post-installation inspection of pipe culverts and LRFD culvert design procedures. The report concludes with recommendations for changes to WYDOT’s specifications related to selection, design, installation, and inspection of culverts.


Malcolm H. Ray

Chuck A. Plaxico

Roadsafe, LLC

FHWA-WY 13/02F (TPF-5(002))

Guide to Standardized Highway Lighting Pole Hardware

ABSTRACT:  This report describes the development of an updated Online Guide to Luminaire Supports. The Guide is a web-based content management system for luminaire support systems that allows full viewing, submission, management, and reporting services to its users (e.g., State DOT personnel, construction contractors, etc.). The Online Guide to Luminaire Supports is one of six online guides maintained by the AASHTO-AGC-ARTBA Joint Committee on New Highway Materials Task Force 13 (TF13). The homepage for the Online Guides can be found online at http://guides.roadsafellc.com/.  The luminaire support systems included in the Online Guide to Luminaire Supports have been successfully crash tested according to NCHRP Report 350 or the Manual for Assessing Safety Hardware (MASH) and comply with the AASHTO Standard Specification for Structural Supports for Highway Signs, Luminaires and Traffic Signals. A link to the appropriate FHWA Eligibility Letter, is included in the index listing for each system.


Rhonda Young, orcid.org/0000-0001-6745-5008

Vijay Sabawat

Promothes Saha

Yanfei Sui

University of Wyoming

FHWA-WY 13/03F (RS04210)

Variable Speed Limit:  Phase 2

ABSTRACT:  The Wyoming Department of Transportation (WYDOT) installed its first variable speed limit (VSL) corridor along Interstate 80 in the Elk Mountain Corridor in the Spring of 2009 in an effort to improve safety and reduce road closures, particularly during winter storm events. Since that time, four additional variable speed limit corridors have been implemented; three additional corridors along segments of Interstate 80 and one on WY 28, a rural two lane highway through the area of South Pass. There were three main objectives to this research effort: develop control strategy for the operation of VSL corridors, analyze the safety effects of the VSL system, and determine the impacts of the VSL on driver speed behavior. For the development of a control strategy, both weather and speed variables were considered. Initially a simple linear regression approach was considered but the complexity of the weather and speed behavior led to a regression tree based control strategy with a self-learning feedback loop using machine learning. For the safety task, descriptive baseline safety was analyzed for all five corridors. Since the Elk Mountain Corridor is the only VSL system in operation for more than two winter seasons, it was used for an Empirical Bayes (EB) before and after analysis, which indicated some statistically significant changes in crash frequency for just a few of the corridor segments. A weather-based safety analysis was performed on the four interstate VSL corridors and results from this analysis indicate a statistically significant reduction in crashes after the VSLs were implemented. Analyses of speed variables indicate a reduction in speed variation with the implementation of the VSL system. Modeling of the difference between observed and posted speeds show a reduction in speed compliance related to large reductions in posted speed limits.


Ryan Fertig

Angela Jones

Margaret Kimble

Darby Hacker

Saadet Toker

Jennifer Eisenhauer Tanner
University of Wyoming

Evaluation of ASR Potential in Wyoming Aggregates

ABSTRACT:  A comprehensive study was performed to evaluate the ASR reactivity of eight Wyoming aggregates.  State-of-the-art and standardized test methods were performed and results were used to classify these aggregate sources. Of the eight aggregates: four are reactive; two are moderately reactive; and two are nonreactive. The Concrete Prism Test (CPT) and large scale field blocks provided the most accurate data.


Stephen Boyles, orcid.org/0000-0001-9734-2311

Center for Transportation Research

University of Texas at Austin


University of Wyoming

FHWA 1305F RS06210

Mesoscopic Traffic Simulation

Abstract:  This study developed a mesoscopic simulator which is capable of representing both city-level and statewide roadway networks. The key feature of such models are the integration of (i) a traffic flow model which is efficient enough to scale to large regions, while realistic enough to represent traffic dynamics, including queue growth and dissipation and intersection control; and (ii) a user behavior model in which drivers choose routes based on minimizing travel times. Integrating these models is nontrivial, because route choices depend on route travel times, but route travel times are determined from route choices through the traffic flow model. An iterative approach is used to seek a consistent solution to this problem, using the cell transmission model as the traffic flow model.

These features have been implemented in a software program, for which source code and tutorials have been provided as appendices to this report. Additional modules are provided for generating graphical views of networks, performing warrant analysis based on MUTCD procedures (either to assist with network creation, or as a post processing step), and a spreadsheet interface to the program itself. Ready-to-use networks have been provided representing the city of Casper and the State of Wyoming.




Larry Redd

Kim Redd

Redd Engineering

FHWA-WY 13/06F (RS02212)

Managing Risks in the Project Pipeline


ABSTRACT:  This research focuses on how to manage the risks of project costs and revenue uncertainties over the long-term, and identifies significant process improvements to ensure projects are delivered on time and as intended, thus maximizing the miles paved and minimizing financial risks to the organization. A dynamic simulation model is validated and tested by researching 50 historical projects, collecting data about these projects, and validating the key inputs for the simulation. A variety of parametric studies, including simulating the effects of various revenue scenarios, are performed and conclusive results are reached. Both Core Strategies, focusing on how to load and manage the project pipeline, and System and Organizational Improvement Strategies are identified. By implementing these strategies and minimizing the amount of projects held “on the shelf” and employing practices that minimize the risks of incurring Holding Costs due to revenue shortfalls, savings can be maximized. Applying new strategies and improving processes will allow the department to better manage the risks facing transportation projects in the project pipeline. Estimated cost savings are between 2 and 4 percent of the total budget; this would amount to a total savings of 90 million dollars, for a budget of 3 billion dollars over a ten-year period. The results of the research are enabling WYDOT to maximize the performance benefits from their asset management efforts.



Debbie S. Shinstine

Khaled Ksaibati, orcid.org/0000-0002-9241-1792

University of Wyoming

FHWA-WY 13/07F (RS09211)

Roadway Safety Improvement Program Indian Reservation

ABSTRACT:  The need to reduce fatal and injury crashes on Tribal lands has been recognized for years. The U.S. has realized a decline in fatal crashes over the past several years but fatal crashes continue to increase on Tribal lands. Little progress has been made in improving safety on Tribal lands. Limited resources and lack of coordination across jurisdictions has made it difficult for Native American communities to address their roadway safety concerns. The rural nature of many of their roadways and lack of crash data has also made it difficult for Tribes to implement an effective safety improvement program. A methodology that is able to address these challenges is presented in this report to assist Tribes in reducing fatal and injury crashes. The proposed methodology has been implemented successfully in the Wind River Indian Reservation. Key to the success of such a process is collaboration among safety stakeholders, namely the State departments of transportation, Tribal leadership, Local Technical Assistance Program (LTAP), Tribal Technical Assistance Program (TTAP), Bureau of Indian Affairs (BIA), and local and Tribal law enforcement.



Corinna Riginos, orcid.org/0000-0001-9082-5206

Kevin Krasnow

Embere Hall

Morgan Graham

Siva Sundaresan

Doug Brimeyer

Gary Fralick

Doug Wachob

Conservation Research Center, Teton Science School

FHWA-WY 13/08F (RS03210)

Understanding Mule Deer Movement


ABSTRACT:  The purpose of this study was to provide the Wyoming Department of Transportation and Wyoming Game and Fish Department with useful information about the patterns of mule deer seasonal habitat use, migration, road crossings, and wildlife-vehicle collisions in the Jackson Hole area. We captured 40 mule deer and fitted them with global positioning system (GPS) collars that collected locations every two hours for up to two years. We identified areas of high seasonal (summer and winter) use by mule deer as well as migration routes between these seasonal ranges. Results show that mule deer use the developed valley of Jackson Hole intensively in the winter months and during migrations. Results of a resource selection function analysis on winter habitat use indicate that deer most intensively use areas close to supplemental feed sites, hill slopes, and areas with high cover of herbaceous vegetation, golf courses, mixed trees, junipers, and riparian vegetation. We further identified 1,796 locations where deer crossed major roadways. Road crossings almost all occurred during winter (rather than summer or migration times) and were concentrated in a few locations. Road crossings were negatively associated with roadside fencing and positively associated with proximity to preferred winter habitat. Finally, we analyzed patterns of deer-vehicle collisions in Jackson Hole. Collisions primarily occurred in winter and were concentrated on US-89/191, particularly on the highest traffic volume stretches near the town of Jackson. These results suggest that any measures designed to reduce the frequency of deer-vehicle collisions will have to allow deer to cross major roadways frequently as they move around their winter home ranges. Crossing structures, which are effective for allowing migrating ungulates to cross roadways, may not be effective for facilitating the frequent crossings of non-migrating animals in a highly developed landscape.


Completed Projects for FY2014 (October 1, 2013 to September 30, 2014)



Thomas Edgar

University of Wyoming

FHWA 14/01F (RS05211)

 Frost Heave Report

Abstract:  This project investigated a novel procedure to reduce or prevent subgrade freezing non-destructively by injecting a two-part polymer foam at the top of the subgrade.  Controlled injection of Uretek Star, expanding structural polymer foam, created a continuous three-inch thick layer of insulation that significantly reduced the heat loss from the deeper soil and almost totally eliminated frost heave at a site on highway WY-70, four and one-half miles west of Encampment, WY. The foam layer also prevented the upward movement of water from the warmer regime under the foam to the upper frozen regime above the foam. This prevented any segregational freezing in the upper zone.

The two-year research project consisted of measuring pavement elevation changes along five 300-foot long lines over the heave area and monitoring subsurface temperatures at six locations inside and outside of the injection zone. The construction time for the 100-foot section was one week for injection and milling the surface. Construction was contained in one lane, leaving a lane open for the entire duration without a detour, increasing safety and minimizing impact for the driving public.  Additionally, a procedure is developed for estimating the thickness of the foam layer required for other sites with different average temperatures.



Edward Offei

Rhonda Young, orcid.org/0000-0001-6745-5008

Khaled Ksaibati, orcid.org/0000-0002-9241-1792

Dick Apronti

University of Wyoming

FHWA 1402F RS08211

Base Widening Methods

Abstract:  The surface transportation system forms the biggest infrastructure investment in the United States of which the roadway pavement forms an integral part. Maintaining the roadways can involve rehabilitation in the form of widening; which require a longitudinal joint between the existing and new pavement sections to accommodate the wider travel lanes, additional travel lanes or modification to shoulder widths. Several methods are utilized for the joint construction between the existing and new pavement sections; vertical, tapered and stepped joints. The main purpose of this research is to develop a formal recommendation as to the preferred joint construction method that provides better pavement support in the State of Wyoming. Field data collection of Dynamic Cone Penetrometer (DCP), Falling Weight Deflectometer (FWD), base samples for gradation and moisture content were conducted on 28 existing and 4 newly constructed widening projects. Survey of practices and preferences of other states, and constructability issues were undertaken. Costs of each joint type were compared as well.

Results of the analysis indicate that the tapered joint technique showed relatively better pavement strength compared to the vertical joint type, and could be the preferred joint construction method. The vertical joint has an 18% increase in cost compared to the tapered joint. This research is intended to provide information and/or recommendation to state policy makers as to which of the base widening joint techniques (vertical, tapered, stepped) for flexible pavement provides better pavement performance.



Rhonda Young, orcid.org/0000-0001-6745-5008

Eric Milliken

Edward Offei

University of Wyoming

FHWA1403F RS07211

Rural Travel Times

Abstract:  Using intelligent transportation systems to help report traveling conditions has been reserved for urban areas. The goal of this research was to help develop a new methodology for incorporating travel times calculated from intelligent transportation system (ITS) technology into Wyoming’s road and weather condition reporting system. Bluetooth sensors and speed sensors were used to measure travel times on I-80 between Cheyenne and Laramie, as well as WY-28 between Farson and Lander in Wyoming. From previous research, the distribution of travel times on I-80 show two distinct modes. Travel times from the WY-28 corridor were then calculated to determine if this trend was common with other rural highways. The next step in this research was to determine the best way to measure travel times on a rural corridor.

Bluetooth sensor travel time data was compared to speed sensor travel time data. Then a travel time index was created for I-80 from one year of speed sensor data. This travel time index was then modeled with weather variables downloaded from road weather information system (RWIS) stations. Finally, a methodology for implementing and evaluating this new travel time reporting procedure was developed. The results of this research will help to improve the current condition reporting system by incorporating both physical conditions (slick in spots, high wind speed, etc.) with travel times. This will help all types of travelers to more accurately quantify the severity of traveling conditions.  



Completed Projects for FY2015 (October 1, 2014 to September 30, 2015)


Kam Weng Ng, orcid.org/0000-0001-5099-5454

Seyed Yashar Yasrobi

Thomas V. Edgar

University of Wyoming

FHWA 0501F RS05213

Approach Slab

Abstract:  Approach slabs serve as a transitional system between an approach road and a bridge. Settlement of bridge approach slabs and their supporting backfill has been experienced by more than ten Departments of Transportation throughout the United States. According to current Wyoming Department of Transportation inspection reports, bridge approach slab settlements occurred not only on existing bridges but also on newly built bridges that were just opened to traffic. These settlements typically create voids ranging from 6-in to 12-in between the base of the approach slab and the geotextile reinforced backfill. This research presents factors causing bridge approach slab settlements and provides necessary design and construction recommendations. A comprehensive literature review pertaining to approach slabs was performed to examine outcomes of research conducted by 12 states. The current specifications and standards on bridge approach slabs of the corresponding states’ Departments of Transportation were also evaluated. A nationwide survey was conducted to fill in the missing knowledge identified in the literature review. The results of the survey are categorized in three groups based on the percentage of bridges experiencing approach slab settlements in that state. Results of the survey show that 46 percent of the total 28 respondents are not satisfied with their current approach slab designs. The survey results revealed that the most common cause of approach slab settlement is poor construction practices. The most important finding of the survey is that performing in-situ tests to control backfill compaction reduces the amount of approach slab settlement. Using the lessons learned from the literature and the results of the survey, potential amendments to current Wyoming Department of Transportation design and construction manuals are recommended.  



Mohamed Ahmed, orcid.org/0000-0002-1921-0724

Mirza Sharif

Khaled Ksaibati, orcid.org/0000-0002-9241-1792

University of Wyoming

FHWA 15/02F RS02214

Effective Shoulder and Centerline Rumble Strips

Abstract:  Lane departure crashes including single-vehicle-run-off-road crashes, opposite direction sideswipe and head-on crashes are considered the most sever crashes and often dominated by sleep deprivation/fatigue, and distracted driving. According to the Federal Highway Administration, 53 percent of annual fatal crashes are attributed to lane and road departures. In Wyoming, lane departure crashes comprised 72 percent of all sever crashes for the years 2008 – 2010. While lane departure crashes are mostly driven by drivers‘ errors, reduction of the frequency and severity can be achieved by more forgiving roadside and specific countermeasures. Rumble strips/stripes are used by many states as a relatively low cost proven safety countermeasure to reduce or prevent lane departure crashes through providing a vibrotactile and audible warning to inattentive motorists. Although the advantages of rumble strips were generally found to outweigh the disadvantages, several issues and concerns have been identified regarding the implementation of rumble strips; noise, maintenance, and the adverse effects on bicyclists and motorcyclists are among the most recognized concerns.

This study demonstrated that despite the fact that rumble strips have been used for many years, there are no standardized practices used in the U.S. A significant number of states are still working on updating their rumble strips policies; their main goal is to enhance motor vehicle safety while accommodating all road users to the highest practical extent. The information provided in this report and the companion Expert System that was developed as part of this study may provide the necessary background for WYDOT and other transportation agencies when it comes to updating or developing an effective all road users‘ friendly rumble strips policy.



Corinna Riginos, orcid.org/0000-0001-9082-5206

Morgan William Graham

Melanie Davis

Chauncey Smith
Andrew Johnson
Teton Research Institute, Teton Science Schools

FHWA-WY-15/03F RS05212

Effects of Wildlife Warning Reflectors

Abstract:  The purpose of this study was to provide the Wyoming Department of Transportation with information about (1) the effectiveness of Streiter-Lite wildlife warning reflectors that had been installed in three locations within Wyoming’s District 5, and (2) preliminary analysis of patterns of deer-vehicle collisions across Wyoming and the habitat and road variables associated with collision hotspots. We evaluated reflector effectiveness in terms of their ability to reduce deer-vehicle collisions and modify deer road-crossing behavior. Using a series of experimental manipulations of reflectors, we showed that reflectors reduced deer-vehicle collisions by 32 percent and significantly reduced the number of high-risk deer road crossings (those in which deer ran into the road as a car was approaching). However, covering reflectors with white canvas bags – initially done with the intent of creating a control treatment that neutralized the reflectors – proved even more effective than leaving the reflectors exposed. White bags on posts resulted in 33 percent fewer collisions than when reflectors were exposed and significantly reduced the number of high-risk deer road crossings. It is likely that the white bags are more visible or reflective to deer than the red wildlife warning reflectors. A cost-benefit analysis suggests that the benefits of reflectors outweigh their initial materials and installation costs, but may not outweigh the net costs once maintenance is taken into account. Analysis of patterns of deer-vehicle collisions across the state showed that traffic volume, proximity to agricultural land, proximity to deer winter range and migration routes, and high speed limits are all strongly associated with high collision rates. On average, areas with a 55 mph speed limit have 36 percent and 55 percent fewer deer-vehicle collisions than areas with speed limits of 65 and 75 mph, respectively. Reducing nighttime speed limits in high collision areas may be a cost-effective strategy for mitigating deer-vehicle collisions in Wyoming.


Continued Evaluation of Field Specimens and Proposed Mitigation Strategies

Margaret Kimble

Ryan Fertig

Darby Hacker

Jennifer Eisenhauer Tanner

University of Wyoming

FHWA-WY-15/04F RS06212

Risk of alkali Silica reaction

Abstract:  A comprehensive study was performed to evaluate the ASR reactivity of eight Wyoming aggregates. State-of-the-art and standardized test methods were performed and results were used to classify these aggregate sources. Of the eight aggregates: one is highly reactive; one is moderately/highly reactive, three are moderately reactive; one is potentially reactive and two are nonreactive. The Concrete Prism Test (CPT) and unboosted large scale field blocks provided the most accurate data.

Mehmet E. Ozbek, PhD
Maral Jalili
Duygu Akalp
Colorado State University
Multi performance measures of Wyoming Highway Patrol
Abstract:  With many lives lost every year in traffic related crashes, traffic safety is a major concern all around the world. One way to improve traffic safety is to improve the organizational performance of agencies responsible for enforcing traffic safety. Internal benchmarking would be the first step to accomplish that goal, in order to compare the units of an organization, identify the best performing ones, and learn from their best practices so that other units within the organization can take advantage and improve their performance as well. Wyoming Highway Patrol (WHP) is a data-driven organization, which uses multiple measures to assess its performance. These measures can be used by WHP to perform comparisons between its 17 divisions. However, this process involves the utilization of a single performance measure at a time and may result in difficulties in identifying the overall performance. Therefore, there is a need to develop a performance assessment framework that can identify the overall performance of these divisions in the presence of multiple measures. This research presents a performance assessment system developed for WHP using Data Envelopment Analysis. This system can incorporate multiple measures, enabling WHP to identify its best-performing divisions to be able to use those as benchmarks.



Hall Sawyer orcid.org/0000-0002-3789-7558

Patrick Rodgers

Western Ecosystems Technology

FHWA-WY-06/01F  RS11211

Overpass and Underpass monitoring Trappers Point

Abstract: The seasonal migrations of ungulates are increasingly threatened by various forms of anthropogenic disturbance, including roads, fences, and other infrastructure. While roadway impacts (i.e., wildlife‐vehicle collisions and landscape permeability) of two‐lane highways to mule deer (Odocoileus hemionus) can largely be mitigated with underpasses and continuous fencing, similar mitigation may not be effective for pronghorn (Antilocapra americana) or other ungulate species that are reluctant to move through confined areas. The Wyoming Department of Transportation recently installed 6 underpasses and 2 overpasses along 20 km of US Highway 191 in western Wyoming, where we evaluated species‐specific preferences by documenting the number of migratory mule deer and pronghorn that used adjacent overpass and underpasses for 3 years following construction. We also measured the amount of back and forth movement across the highway for each species through time. We documented 40,251 mule deer and 19,290 pronghorn migrate across the highway. Of those, 79% of mule deer moved under, whereas 93% of pronghorn moved over the highway. These strong species‐specific differences were evident at both sites and support the notion that overpasses are more amenable to pronghorn than underpasses. Concurrently, we documented a sharp increase in the amount of back and forth movement of mule deer and pronghorn across the highway during migration periods. Such movement flexibility is presumed to improve their ability to respond to changing environmental conditions by easily accessing habitats on either side of the highway. Our results highlight that species‐specific preferences are an important consideration when mitigating roadway impacts with wildlife crossing structures. Overpass and underpass construction reduced wildlife‐vehicle collisions by approximately 81%.



Biplab B. Bhattacharya, orcid.org/0000-0003-3003-9347

Harold L. Von Quintus  orcid.org/0000-0003-4030-6162

Michael I. Darter

Applied Research Associates

FHWA 16/02F  RS03209

Local Calibration of MEPDG

Abstract:  This report documents the local calibration of the transfer functions using LTPP and non-LTPP roadway segments. The calibration process follows the steps presented in the 2010 AASHTO MEPDG Local Calibration Guide. Local calibration coefficients were derived to remove that bias for the rutting, fatigue cracking, and thermal cracking transfer functions of flexible pavements, and the faulting and fatigue cracking transfer functions of rigid pavements. The global coefficients of the smoothness degradation regression equation for flexible and rigid pavements were also checked for their applicability to Wyoming conditions.

RELATED ARTICLE:  Systematic back-calculation protocol and prediction of resilient modulus for MEPDG.  http://dx.doi.org/10.1080/10298436.2016.1162303


Mohamed M. Ahmed, Ph.D., P.E. - orcid.org/0000-0002-1921-0724

Khaled Ksaibati, Ph.D., P.E. - orcid.org/0000-0002-9241-1792
Sherif Gaweesh, M.S. - orcid.org/0000-0001-7977-6378
Md. Hamidur Rahman - orcid.org/0000-0002-8002-2925
Ali Ghasemzadeh, M.S. - orcid.org/0000-0003-1232-251X
Anemone Kasasbeh - orcid.org/0000-0002-1379-7499
Regulatory Headlight Signs
Abstract:  Although Daytime Running Lights (DRLs) may have a significant impact on increasing vehicle conspicuity during different times of the day, their effect on overall safety is still up for debate. A recent study by the U.S. Department of Transportation (USDOT) National Highway Traffic Safety Administration (NHTSA) showed that DRLs offer no statistically significant reduction in the frequency or severity of crashes analyzed. There are functional issues with using automatic DRLs only: drivers with automatic DRLs often do not turn on their low-beam headlights in adverse weather conditions and at dusk or dawn. This is especially dangerous because the taillights do not come on until the low-beam headlights are turned on manually. This becomes more important at hazardous roadway sections that require both headlights and taillights.
This project investigated the impact of the compliance rate, and the density of the DRL technology on the safety benefits of regulatory headlight signs on mountainous and non-mountainous rural two-lane highways. The safety effectiveness of headlight signs was examined based on DRLs-equipped and non-DRL- equipped vehicles. Simple odds and ratio of odds ratios were utilized to adjust for a variety of exogenous factors. Four different scenarios were considered in analyzing crash data. A case-control method was used to compare crashes for a set of passenger vehicles equipped with DRLs and vehicles without DRLs on roadway sections with and without headlight signs. The low compliance rate to the mandatory headlight sign may result in misleading conclusions about the safety benefits of the regulatory headlight signs. A careful analysis should be carried out to quantify the actual benefits. Development of social media campaigns might be necessary to raise public awareness about the importance of complying with the mandatory headlight use signs.


Dick T. Apronti, orcid.org/0000-0002-2072-2030; 
Jaime J. Herpner, orcid.org/0000-0002-3677-7386; 
Khaled Ksaibati, Ph.D., P.E., orcid.org/0000-0002-9241-1792

FHWA1604F RS06213

Low Volume Roads

Abstract:  Low-volume roads are excluded from regular traffic counts except on a need to know basis. But needs for traffic volume data on low-volume roads in road infrastructure management, safety, and air quality analysis have necessitated regular traffic volume estimates. This study developed traffic volume estimation models for low-volume roads in Wyoming. A review of existing estimation models was carried out. Two main model types were identified - regression models and Travel Demand Models (TDMs). The study developed the two model types and recommended the best model for implementation. Two regression models were developed, a linear and a logistic regression model. Each of the regression models was developed using data from 13 randomly selected counties and nine counties were used in model validation. The linear regression model had an R2 of 64 percent and was verified to be a good predictor of traffic volumes across Wyoming. The logistic regression model validation indicated a prediction accuracy ranging from 78 to 89 percent. The TDM was developed using standard factors and trip rates in the NCHRP Report 365. The TDM was implemented for four south eastern counties in Wyoming. The model was then validated and calibrated by comparing actual traffic volumes to those generated by the model. The calibrated model had a Percentage Root Mean Square Error and an R2 values of 50 and 74 percent respectively. The report compared the three models with respect to cost-effectiveness, ease of use, and accuracy and recommended the TDM for implementation. The regression models were recommended for applications requiring quick traffic volume estimations and for which lower levels of accuracy are acceptable.



Richard J. Schmidt  orcid.org/0000-0003-1672-2625
Structural Health Monitoring Phase I
Abstract:  The long-term objectives of this project were to develop and validate an instrumentation package for structural health monitoring of bridges subjected to overweight trucks and to develop plans for field deployment of the instrumentation on a pilot scale. Ultimately, the objective is to accurately correlate long-term field performance data to the behavior of the bridges predicted by analysis and rating software.
In Phase I of the project, instrumentation, packaging, installation techniques and data collection and storage for fiber Bragg grating (FBG) sensors were be developed in the laboratory. The essential elements of the structural health monitoring (SHM) system are in place and include (a) sensor installation and protection techniques for both concrete and steel host structures, (b) commercial and special-purpose instrumentation for interrogating the SHM network, and (c) a triggering system based in RFID technology to control the amount of data that is collected by the SHM network.
Subsequent deployment of the system on a bridge in the WYDOT inventory will require additional development of data storage and transmission capabilities, which will be particular to the location and characteristics of the targeted bridge. Researchers engaged in Phase II of this study must coordinate with bridge engineers at WYDOT to identify a spectrum of SHM applications and objectives, for which individual data analysis techniques can be developed. Subsequent design and implementation of software to execute such data analysis will be needed to relieve bridge engineers from the burdensome and tedious tasks of sifting through raw SHM data streams themselves.


Kim Basham, PhD, PE, FACI

FHWA-WY-16/07F; RS04211

Silica Fume Bridge Deck Overlay

Many of these microsilica-modified concrete or silica fume concrete (SFC) bridge deck overlays across the State of Wyoming are suffering from premature distress that includes random cracking, loss of bond and delaminations. To determine the most likely cause of the premature overlay failures and to develop a mitigation scheme, this author with the assistance of Dr. David Rothstein, PhD, PG, FACI with DRP Consulting, Inc. (DRP) and Mr. Larry Mott, PE with GES Tech Group, Inc. (GES) undertook a multi-task research study.
Tasks consisted of measuring bond strengths of existing and new SFC overlays representing different surface preparation techniques and measuring both plastic and hardened properties including drying shrinkages for typical SFC overlay mixtures. DRP performed petrographic examinations of bond lines and failure zones of core samples. GES modeled the overlay and substrate and performed non-linear finite element analyses focusing on the cracking potential of the overlay and the bond-line stresses created by varying the strength and drying shrinkage of the overlay.
Results show bond strengths for most of the existing and new SFC overlays was insufficient. In general, bond strength failures occurred superficially in the concrete substrate and the petrographic examinations revealed cracks and microcracks located within the top ¼ inch of the substrate, most likely caused by an external applied stress after initial bonding. The finite element analyses showed significant tensile stresses in the overlay material, shrinkage cracks and high bond-line stresses occurred when the drying shrinkage of the SFC overlay exceeding about 0.03 percent. Results indicate the magnitude of the drying shrinkage of the existing SFC overlays was too large.
Using the 0.03 percent as the upper limit for the field shrinkage, maximum 28-day allowable shrinkages as determined by a standard laboratory procedure were computed using a concrete shrinkage model for different overlay thickness and relative humidities. By limiting the 28-day laboratory shrinkages, SFC overlay shrinkages should not exceed 0.03 percent; thereby, limiting the cracking potential of the overlay and maintaining acceptable bond line stresses.



Mohamed M. Ahmed, Ph.D., P.E. orcid.org/0000-0002-1921-0724

Ali Ghasemzadeh, M.Sc. orcid.org/0000-0003-1232-251X

Hesham Eldeeb, Ph.D.

Sherif Gaweesh, M.Sc. orcid.org/0000-0001-7977-6378

Rhonda Young, P.E., Ph.D. orcid.org/0000-0001-6745-5008

Joshua Clapp, Ph.D.

FHWA - WY - 16/08F; RS04215

SHRP2 Safety Data

Inclement weather events such as fog, snow, ground blizzard, slush, rain, and strong wind affect roadways by mpacting pavement conditions, vehicle performances, visibility, and drivers’ behavior. Road-user characteristics and behavior are among the most important elements influencing the driving task. The ability to see objects that are in motion relative to the eye (“dynamic visual acuity”) and the reaction process (e.g., speed choice, lane maintenance, car following, etc.) are of utmost importance for safe driving. Adverse weather conditions can result in a sudden reduction in visibility on roadways, which leads to an increased risk of crashes. The literature shows a variation of crash risk estimates; however, a general trend can be concluded that adverse weather and road conditions can easily elevate the risk of crashes. Drivers' performance and behavior are absent in safety modeling due to lack of driver data. The second Strategic Highway Research Program (SHRP2) has collected the most comprehensive Naturalistic Driving Study (NDS). The unique NDS data will enable researchers to better understand the role of driver performance and behavior under various highway research.


Minwoo Chang orcid.org/0000-0002-5749-078X

Marc Maguire  orcid.org/0000-0002-7897-0344

FHWA - WY-16/09F; RS04214

Bridge Deterioration Models

Deterioration models for the Wyoming Bridge Inventory were developed using both stochastic and deterministic models. The selection of explanatory variables is investigated and a new method using LASSO regression to eliminate human bias in explanatory variable selection. The cross validation technique is used to determine the minimum number of explanatory variables. The relative significance of candidate variables is used to rank the explanatory variables in hierarchical order.

The deterministic deterioration models are developed by using curve-fitting methods for the mean of bridge ages for each condition rating. In order to improve the accuracy in the model, bridges are split into the multiple subsets using first two explanatory variables for deck, superstructure, and substructure. Although the deterministic deterioration model is insufficient to predict condition ratings for a specific bridge, it is worthy to observe a general feature of how the functionality of bridges becomes worse over time.

The stochastic models are developed to capture the uncertainty in the deterioration process using the Markov chain. The transition probability matrix is estimated using percentage prediction method, which counts the numbers corresponding to the element of transition probability matrix. The same subsets used in the deterministic deterioration models are considered. For each subset, zoning technique is used such that the bridge data is grouped for every 30 years to estimate transition probability matrix separately.

The source codes are provided for the future update of bridge inventory and stochastic deterioration models. A computer program is used develop and plot deterioration models. A simple guideline is also included so that the user can access the source codes conveniently.



Corinna Riginos  orcid.org/0000-0001-9082-5206
Holly Copeland orcid.org/0000-0001-8613-2650
Chauncey Smith orcid.org/0000-0001-8861-6763
Hall Sawyer orcid.org/0000-0002-3789-7558
Kevin Krasnow orcid.org/0000-0002-0887-2503
Thomas Hart orcid.org/0000-0002-3246-7049
Wildlife Vehicle collisions and migration routes
Wyoming is home to abundant big game, including long-distance migratory species such as mule deer, elk, and pronghorn. Where these animals’ movement patterns intersect with roads, vehicles often hit animals. This poses a threat both to highway safety and to wildlife populations. Here, we identified 27 deer-vehicle collision “hotspots” in the state. We then analyzed the ecological and road characteristics that are associated with these areas. High rates of deer-vehicle collision are most strongly associated with high traffic volumes, high speed limits, deer migration habitat, deer winter-use areas, irrigated agriculture, and wetlands. We then examined the spatial and temporal patterns of collisions for each hotspot in relation to known deer migration routes and winter-use areas. Using these results, we suggest mitigation measures that are most suitable for each of the 27 collision hotspots.

Completed Projects for FY2017 (October 1, 2016 to September 30, 2017)




Kam Weng Ng  orcid.org/0000-0001-5099-5454

Harold L. Von Quintus  orcid.org/0000-0003-4030-6162

Khaled Ksaibati  orcid.org/0000-0002-9241-1792

Daniel Hellrung  orcid.org/0000-0003-3400-394X

Zachary Hutson  orcid.org/0000-0003-3913-9184

FHWA-WY-1701F; RS04213


The Wyoming Department of Transportation (WYDOT) recently transitioned from the empirical AASHTO Design for Design of Pavement Structures to the Mechanistic Empirical Pavement Design Guide (MEPDG) as their standard pavement design procedure. A comprehensive field and laboratory test program was conducted in Wyoming to characterize the properties of unbound soil materials. The field test program included falling weight deflectometer (FWD), dynamic cone penetration (DCP), standard penetration test (SPT), soil sampling and pavement distress survey. The laboratory test program included standard soil classification tests, R-value test, standard Proctor compaction test, and resilient modulus (Mr) test in accordance with a protocol by modifying the AASHTO T-307 procedure. All test data was stored and managed by an electronic WYOming MEPDG Database (WYOMEP). Using the FWD data, in-place resilient modulus (MR) of each pavement layer was back-calculated using MODCOMP6 and EVERCALC. For MEPDD Level 2 input, correlation studies were performed to adjust back-calculated modulus to laboratory-derived modulus, calibrate constitutive models, develop relationships between resilient modulus and other soil properties, and develop Mr design tables. Furthermore, tables of unbound soil properties were established for MEPDG Level 3 input. Finally, seven pavement designs were evaluated and compared to achieve the target threshold values and reliability level. The design comparisons and resulting outcomes or predicted distresses for a range of new pavement and rehabilitation designs were presented. The outcomes of these trial examples were used to provide revisions to the 2012 WYDOT MEPDG User Guide. 


Michael Barker

Jay Pucket

FHWA-WY-1702F; RS03214

RS03214 I-80 Truck Load Study.bmp

The research objective is to examine the safety of Wyoming bridges on the I-80 corridor considering the actual truck traffic on the interstate based upon weigh in motion (WIM) data. This was accomplished by performing statistical analyses to determine reliability indices for a set of archetype bridges. This set of bridges include simple-span bridges with lengths between 30 ft and 200 ft (positive moments) and two-span bridges with equal spans lengths of 30 ft to 200 ft (negative moments). Adequate safety, as defined by AASHTO Bridge Specifications, is a reliability index of at least 3.50. Wyoming DOT has several years of truck characteristics that were used to develop a live load model in a manner similar to the NCHRP used to calibrate the LRFD Specifications. The results are the live load bias values and coefficients of variations for the different bridge archetypes that are used to determine the 75-year maximum load statistical properties for the reliability analyses.
Three optimally designed steel bridges from the NCHRP 20-7/186 report with varying ratios of dead, wearing surface, and live loads are used to perform the reliability analyses and assess safety. Truck traffic along I-80 creates more demand than that assumed in the AASHTO LRFD bridge design procedures. The greater demand results in reliability indices that do not meet target safety levels and have reliability indices significantly less than 3.5. Two issues should be addressed: (1) the unacceptably low reliability indices for short multi-span bridges (2) the overall low reliability indices for all span lengths.
The “optional” (low-boy) dual tandem load where there is a tandem in adjacent spans in the AASHTO LRFD commentary significantly increases the negative design live load moments. Using the dual tandem, the reliability indices for the shorter two-span bridges increase to 3.00 and above, placing this bridge type into the range of the reliability indices for the other bridge span lengths. However, indices are below the target. Raising the design live load factor, L, directly and fairly uniformly increases reliability indices. An increase in L to 2.00 (from 1.75) increases almost all of the reliability indices above 3.50. 
In summary, the “optional” low boy load should be used for design and will control shorter multiple-span bridges in the negative moment region.



Noriaki Ohara, Ph.D, orcid.org/0000-0002-7829-0779

FHWA-WY-1703F; RS 06215


Snow fence is an effective hazard mitigation measure for the low visibility and low friction of the road surface under winter weather condition.  Prevailing wind directions and snow precipitation data prepared by Dr. R. Tabler (the Tabler data) that are necessary for snow fence design have not been updated since the 1990s.  This project provides new, seamless wind field and snow precipitation data under the adverse winter storm conditions during 1980-2014, using the Weather Research and Forecasting (WRF) model with North American Regional Reanalysis (NARR) data input.  The simulated wind fields were successfully validated by using the observed data from airport sites and using the Tabler data.  The WRF simulated precipitation data were assimilated to the observation-based PRISM data in order to obtain the accurate hourly snow precipitation data.  Combining all the weather variables, the number of blowing snow events is found to be increasing despite the increasing air temperature because of the sufficiently cold winters of Wyoming.  Finally, it was verified that the existing snow fence system is effective under the winter season prevailing wind since the simulation agrees with the Tabler data.  However, it was also found that the simulated wind patterns during the blowing snow events can be quite different from the winter season average prevailing wind field.  Moreover, the historical wind statistics indicated large deviations in wind direction along I-80.