Wyoming Department of Transportation

Final Projects FY2009 to FY2013




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


FHWA-WY 09/01F (RS02207)

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.


FHWA-WY 09/02F (RS06206)


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.


FHWA-WY 09/03F (RS10206)

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)



 FHWA-WY 09/05F (RS05205)

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.


FHWA-WY 09/06F (RS01207)

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.


 FHWA-WY09/07F (RS02208)

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.


FHWA-WY 09/10F (RS07209)

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)


FHWA-WY 10/01F (RS04206)

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.


FHWA-WY 10/02F (RS01210)

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. 



 FHWA-WY 10/03F (RS06209)





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.


FHWA-WY 10/04F (RS05207)

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.


FHWA-WY 10/05F (RS06207)

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.


FHWA-WY 10/06F (RS07210)

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.


FHWA-WY 10/07F (RS04209)

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)


FHWA-WY 11/02F (RS01209)


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.


FHWA-WY 11/03F (RS07207)

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)



FHWA-WY 12/02F (RS03211)

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.


 FHWA-WY 12/03F (RS08210)

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)


FHWA-WY 13/01F (RS10211)

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.


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

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.


FHWA-WY 13/03F (RS04210)

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.


FHWA-WY 13/04F (RS06212)

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.


FHWA 1305F RS06210

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.



FHWA-WY 13/06F (RS02212)


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.



FHWA-WY 13/07F (RS09211)

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.



FHWA-WY 13/08F (RS03210)


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)



FHWA 14/01F (RS05211)


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.



FHWA 1402F RS08211

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.



FHWA1403F RS07211

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)


Investigation of Approach Slab and its Settlement for Roads and Bridges

FHWA 0501F RS05213

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.

Developing an Effective Shoulder and Centerline Rumble Strips/Stripes Policy to Accommodate All Roadway Users

FHWA 15/02F RS02214

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.


Effects of Wildlife Warning Reflectors (Deer Delineators) on Wildlife Vehicle Collisions in Central Wyoming

FHWA-WY-15/03F RS05212

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.



Back to Top