Engineering Commons^™

Evaluation Of Opportunities And Challenges Of Using Inrix Data For Real-Time Performance Monitoring And Historical Trend Assessment, Anuj Sharma, Vesal Ahsani, Sandeep Rawat

Nebraska Department of Transportation: Research Reports

In recent years there has been a growing desire for the use of probe vehicle technology for congestion detection and general infrastructure performance assessment. Unlike costly traditional data collection by loop detectors, wide-area detection using probe-sourced traffic data is significantly different in terms of measurement technique, pricing, coverage, etc. This affects how the new technology is applied and used to solve current traffic problems such as traffic incident management and roadway performance assessment. This report summarizes the experiences and lessons learned while using probe data for traffic operations and safety management in the state of Nebraska and makes recommendations for …

Effectiveness Of Chain Link Turtle Fence And Culverts In Reducing Turtle Mortality And Providing Connectivity Along U.S. Hwy 83, Valentine National Wildlife Refuge, Nebraska, Usa, Marcel P. Huijser, Kari E. Gunson, Elizabeth R. Fairbank

Nebraska Department of Transportation: Research Reports

We evaluated the effectiveness of existing turtle fences through collecting and analyzing turtle mortality data along U.S. Hwy 83, in and around Valentine National Wildlife Refuge, Nebraska, USA. We also investigated the level of connectivity for turtles provided through the culverts that were originally designed to pass water through a capture-mark-recapture experiment. While fenced valley sections had 33.1% fewer turtle observations than unfenced valley sections, the difference was not significant. However, we think that the effectiveness of the fence can be improved through fence repairs, other modifications of the fences, vegetation maintenance, and extending the length of the fences. Four …

Increased Span Length For The Mgs Long-Span Guardrail System Part Iii: Failure Analysis, Sagheer A. Ranjha, Robert W. Bielenberg, John D. Reid, Ronald K. Faller

Nebraska Department of Transportation: Research Reports

The objective of this research study was to review and analyze the system failure observed during crash testing of an increased span length for the MGS long-span guardrail system in test no. MGSLS-2. Test no. MGSLS-2 was a full-scale crash test conducted on the MGS long-span guardrail with a span length of 311⁄4 ft (9.5 m). This test utilized universal breakaway steel posts (UBSPs) adjacent to the long span in lieu of the controlled release terminal (CRT) wood posts used in previous long span systems.

An engineering analysis was undertaken to review the downstream end anchorage failure observed in test …

Improving Wildflower Longevity In Roadside Seeding Areas, Walter Schacht, Jonathan M. Soper, Carol Wienhold

Nebraska Department of Transportation: Research Reports

Re-vegetation efforts on bare roadsides of newly-constructed highways are primarily focused on the stabilization of soil to reduce rates of erosion. The Nebraska Department of Transportation (NDOT) seeds roadsides with a diverse mixture of grasses and wildflowers for site stabilization as well as to enhance the visual quality of roadsides. Although grasses dominate roadside plantings in terms of cover and density, wildflowers are largely responsible for the visual enhancement of recently-seeded roadsides. In addition to the visual component, wildflowers provide essential ecological functions on roadsides. Wildflowers improve water and nutrient cycling in the compacted roadside soils by increasing water infiltration …

Broadening Understanding Of Roundabout Operation Analysis: Planning-Level Tools And Signal Application, Ahmed Buasali

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

In United States, roundabouts have recently emerged as an effective and efficient alternative to conventional signalized intersections for the control of traffic at junctions. This thesis includes two investigations related to the operations of roundabouts.

The first investigation examines the ability of a planning-level tool (the critical sum method) to serve as an indicator variable for the results of the Highway Capacity Manual’s average delay per vehicle measure for a roundabout facility; to what extent do the results of one predict the results of the other? The critical sum method was found to accurately predict the HCM average delay per …

Evaluation Of Adjustable Continuity Joint Variations For Use In The Restore Barrier, Scott Rosenbaugh, Jennifer D. Schmidt, Ronald K. Faller, James C. Holloway

Nebraska Department of Transportation: Research Reports

During MASH TL-4 full-scale crash testing of the RESTORE barrier, concrete cracking and spalling was observed on the barrier beams that would likely require repairs or replacement. This study sought to evaluate joint design alternatives for use in the RESTORE barrier in order to limit the amount of system damage. Three variations of the Adjustable Continuity Joint (ACJ) were identified as potential modifications: 1) incorporating rubber bearing pads within the ACJ, 2) utilizing normal weight concrete instead of lightweight concrete, and 3) incorporating a steel end cap into the ends of the beam segments.

Four dynamic component tests were conducted …

Injury Severity Of Truck Drivers In Crashes At Highway-Rail Grade Crossings, Waleed Ali Khan

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

There is a noticeable difference between different road users, specifically between passenger vehicles and heavy vehicles such as its length and weight. The majority of previous research were focused on general highway traffic that included passenger cars, trucks, buses, motorcycles, etc. Moreover, HRGC safety studies of specific types of vehicles are relatively few and heavy vehicle safety at grade crossing is even more under-explored.

This research thus focuses on the following objectives: Identify factors related to different injury severity levels of heavy-vehicle drivers (truck/truck-trailer) drivers in crashes reported at HRGCs; to identify a more suitable statistical model for injury severity …

Condition Factor Calibration For Load And Resistance Factor Rating Of Steel Girder Bridges, Joshua Steelman, Pranav M. Shakya

Nebraska Department of Transportation: Research Reports

Load and Resistance Factor Rating (LRFR) is a reliability-based rating procedure complementary to Load and Resistance Factor Design (LRFD). The intent of LRFR is to provide consistent reliability for all bridges regardless of in-situ condition. The primary difference between design and rating is the uncertain severity and location of deterioration, including the potential future loss of strength for an element already evidencing deterioration. Ostensibly, these uncertainties are addressed by applying an additional strength reduction factor: the condition factor, ϕc. Currently, condition factors are nominally correlated to the condition of the member, which can be Good, Fair, or Poor. However, definitions …

Evaluation Of Floorpan Tearing And Cable Splices For Cable Barrier Systems, Scott K. Rosenbaugh, Jason A. Hartwell, Robert W. Bielenberg, Ronald K. Faller, James C. Holloway, Karla A. Lechtenberg

Nebraska Department of Transportation: Research Reports

This research effort consisted of two objectives related to components of a prototype cable barrier system. The first objective was to mitigate the potential for vehicle floorpan tearing by modifying the cable guardrail posts. A bogie vehicle was equipped with a simulated floorpan designed to replicate the height, thickness, and strength of the floorpan of a Kia Rio vehicle. Baseline testing demonstrated that the top of the Midwest Weak Post (MWP) would contact, and crease the simulated floorpan, which matched the damage observed in actual full-scale vehicle crash tests. Once the test setup provided the desired results, various post configurations …

Mash Test No. 3-10 Of A Non-Proprietary, High-Tension Cable Median Barrier For Use In 6h:1v V-Ditch (Test No. Mwp-8), Dylan T. Meyer, Karla A. Lechtenberg, Ronald K. Faller, Robert W. Bielenberg, Scott K. Rosenbaugh, John D. Reid

Nebraska Department of Transportation: Research Reports

The Midwest States Pooled Fund Program has been developing a prototype design for a non-proprietary, high-tension cable median barrier for use in a 6H:1V V-ditch. This system incorporates four evenly spaced cables, Midwest Weak Posts (MWP) spaced at 8 to 16 ft (2.4-4.9 m) intervals, and a bolted, tabbed bracket to attach three or four cables to the sides of each post. According to the Manual for Assessing Safety Hardware (MASH) testing matrix for cable barriers installed within a 6H:1V median V-ditch, a series of eight full-scale tests are required to evaluate the safety performance of a system. A ninth …

Length Of Need And Minimum System Length For F-Shape Portable Concrete Barrier, Robert W. Bielenberg, Dylan T. Meyer, Ronald K. Faller, John D. Reid

Nebraska Department of Transportation: Research Reports

Portable concrete barrier (PCB) systems are often used to redirect errant vehicles through a combination of inertial resistance, lateral friction loads, and tensile loads developed from the mass and friction of the barrier segments. State departments of transportation (DOTs) and other end users may wish to utilize minimal length PCB installations to shield a hazard or work zone or limit the number of barriers required on the upstream and downstream ends to reduce overall system length. However, concerns with the performance of shorter PCB installations include increased lateral deflections and working widths and barrier pocketing. Additionally, no impact testing has …

Testing And Evaluation Of Mash Tl-3 Transition Between Guardrail And Portable Concrete Barriers, Robert W. Bielenberg, Jessica L. Lingenfelter, Justine E. Kohtz, Ronald K. Faller, John D. Reid

Nebraska Department of Transportation: Research Reports

Three full-scale vehicle crash tests were conducted according to the Manual for Assessing Safety Hardware (MASH) Test Level 3 (TL-3) safety performance criteria on a transition between the Midwest Guardrail System (MGS) and a portable concrete barrier (PCB) system. The transition system utilized for test nos. MGSPCB-1 through MGSPCB-3 consisted of a standard MGS that overlapped a series of F- shape PCB segments that approached the MGS at a 15H:1V flare. In the overlapped portion of the barrier systems, uniquely-designed blockout holders and a specialized W-beam end shoe mounting bracket were used to connect the systems.

In test no. MGSPCB-1, …

Design And Evaluation Of Modified Centerline Rumble Strips, Yong-Rak Kim, Tae Sun You, Laurence Rilett

Nebraska Department of Transportation: Research Reports

A centerline rumble strip (CLRS) is primarily installed on the centerline of undivided two-lane and two-way roadways to alert drivers that they are moving out of their intended travel lane. The main purpose of CLRSs is to reduce crossover collisions typically caused by inattentive, distracted, drowsy, or fatigued drivers. Despite the safety benefits, CLRSs that were milled over or adjacent to the centerline joint may increase or accelerate the deterioration and degradation of the pavement structure, which has been observed in Nebraska pavements. In this research project, new (or modified) CLRS designs were sought to reduce pavement damage, while satisfying …

Increased Span Length For The Mgs Long-Span Guardrail System Part Ii: Full-Scale Crash Testing, Dylan T. Meyer, John D. Reid, Karla A. Lechtenberg, Robert W. Bielenberg, Ronald K. Faller

Nebraska Department of Transportation: Research Reports

The objective of this research study was to design and evaluate the MGS long-span design for use with unsupported spans greater than 25 ft (7.6 m). Two full-scale crash tests were conducted to evaluate the MGS long-span system with increased span lengths and the use of UBSP posts adjacent to the long span. Both tests were conducted according to the TL- 3 criteria outlined in MASH. Both test nos. MGSLS-1 and MGSLS-2 were conducted with the 2270P vehicle impacting their respective critical impact points at a speed of 62 mph (100 km/h) and an angle of 25 degrees. Test no. …

Ls-Dyna® Modeling Enhancement Support, John D. Reid, Robert W. Bielenberg, Chaz Ginger

Nebraska Department of Transportation: Research Reports

The Pooled Fund Program member states provided funding for LS-DYNA modeling enhancements in Years 17 thru 22 (2006-2011), with a project period of 2006-2016. This report documents many of the modeling issues addressed throughout the project period. The funding has been effectively utilized to advance the current state-of-the-art for computer simulation and has provided the following benefits for the entire industry: (1) improved roadside safety hardware, (2) reduced development time and cost, (3) improved understanding of the behavior of roadside safety features, especially for impacts outside of normal crash test conditions, (4) improved LS-DYNA modeling techniques and procedures, and (5) …

Evaluation Of Tack Coating Practices For Asphalt Overlays In Nebraska, Soroosh Amelian, Yong-Rak Kim

Nebraska Department of Transportation: Research Reports

The strength of the bond between asphalt layers affects the lifespan of pavement structures. It is also a key factor in preventing major pavement distresses, such as slippage cracking and delamination. This research project evaluates and compares the effectiveness and performance of different tack coating approaches to ensure the proper bond strength is achieved in asphalt concrete (AC) interlayers through an experimental study. Various tack coat materials, including different types of emulsified asphalt and asphalt binders, at multiple application rates and dilution ratios were investigated. In the first part of this study, laboratory-prepared samples were used to evaluate the sensitivity …

In-Vehicle Evaluation Of Rumble Strips In Pre-And Post-Chip Sealed Maintenance Periods, Ernest Tufuor, Laurence Rilett

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Chip sealing will reduce the depth of rumble strips (RS) by approximately 1/8".  Will this depth reduction affect RS functional characteristics (audible and tactile warnings)?

There is no detailed study on the effectiveness of RS that have been chip sealed. USEFULNESS The results will be useful to the Nebraska Department of Roads to determine:

Operations: Whether RS will need to be re-milled after chip sealing. Cost & safety implications.

Design: New RS guidelines for highways expected to be chip sealed in the future.

It can be shown that a 1/8" reduction in the current milled RS design depth, as …

Optimizing Steel Railway Truss Bridge Health Monitoring, Ahmed Rageh, Daniel Linzell

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Problems - Steel Railway Trusses • Aging • Large system – bridge AND railway • Labor intensive condition eval • Reported conditions: Stringer-to-floor beam connections [Haghani 2012] Stringer flange clip angle cracks [Haghani 2012] Unequal eyebars stress distribution [DelGrego 2008] Displaced eyebar pins [DelGrego 2008

Problems – Condition Evaluation • Visual inspection: Prescribed frequency Costly Subjected to human interpretation • Sensors: Focused on a single bridge Extensive array Costly

Influence Of Skew And Nonlinear Deck On Elastic Versus Inelastic Distribution Behavior And Ultimate Capacity Of Steel Girder Bridges, Fayaz Sofi, Joshua Steelman

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Research Objectives

• Assessment of alternative load distribution methodologies for potential discrepancies that arise when evaluating distribution behavior of skewed steel girder bridges.

• Investigate the influence of skew and material nonlinearities (concrete cracking and steel yielding) on

• Load distribution behavior (elastic versus inelastic).

• System capacities (yielding and ultimate).

Summary and Conclusions • Influence of skew was examined on load distribution behavior, and nonlinear system-based capacities (yielding and ultimate) of composite steel girder bridges in presence of full material nonlinearities. In addition, assessment of two general definitions (beam-line and response fraction approaches) for quantifying load distribution behavior was …

Indicators Of Assessing Vehicle Safety Status Under Platoon Conditions At Freeway, Jianan Zhou

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Issue on level freeway segment (Interstate 80) in Nebraska: • High truck percentage (higher than 25%) • Different speed profile - The speed of trucks are set to 67 mph, on average. - The speed of passenger cars are 75 mph, on average. • Result platoons - Approximately 85% of vehicles are observed in platoon. - the degree of freedom to maneuver for drivers are constrained by other in-platoon vehicles. - Vehicles in platoons may face unsafe situation. Goal: Develop indicators to assess the safety status of vehicles under platoon conditions at level freeway segment.

The data were collected at …

Protocol To Evaluate And Load Rate Existing Bridges, Maria Szerszen, Ali Alhajami

Nebraska Department of Transportation: Research Reports

Load tests can be used to verify component and system performance under a known live load and provide an alternative evaluation methodology to analytically computed the load rating of a bridge. Procedures for nondestructive load testing, which involves field observations and measurements of in- service bridges and field testing often can revel additional capacity since analytical bridge rating tend to be fairly conservative. The goal of presented research was to develop a data-driven rating process to assess and rate bridges. This data-driven rating system reduces the subjective judgment of the bridge inspectors through the use of computer models and field …

Assessing Passenger Car Equivalency Factors For High Truck Percentages, Jianan Zhou, Laurence Rilett, Elizabeth Jones

Nebraska Department of Transportation: Research Reports

The Passenger Car Equivalent (PCE) values in the Highway Capacity Manual (HCM) 2010 might not be valid for western Nebraska freeway conditions. This is because: 1) Interstate 80 (I-80) experiences high truck percentages (25% to 60%), while the HCM provides PCE values up to 25% of the truck percentage; 2) the average speed of trucks are observed lower than passenger cars, which is incompatible with the HCM assumption that the free speed of all vehicle types is the same at level terrain; and 3) it is unclear whether the “average” truck used in the simulation study for PCE values in …

Design And Implementation Of The Manitoba Constrained-Width Tall Wall Barrier, Harald P. Larsen, Scott K. Rosenbaugh, Andrew Pankratz, Diana Emerson, Jennifer Schmidt, Ronald K. Faller, Elizabeth M. Regier

Mid-America Transportation Center: Final Reports and Technical Briefs

Manitoba Infrastructure (MI) desired a new, tall concrete median barrier capable of satisfying the Test Level 5 (TL-5) safety requirements of the Manual for Assessing Safety Hardware (MASH). It needed to fit within the footprint of an existing F-shape median barrier located in a narrow median. It also was required to address headlight glare from opposing traffic. The barrier was designed with a height of 1,250 mm, a maximum width of 600 mm and to resist a load of 845 kN applied at the top of the barrier. The Manitoba Constrained-Width, Tall Wall was optimised to withstand the design load …

Cive 463: Traffic Engineering—A Peer Review Of Teaching Project Benchmark Portfolio, John Sangster

UNL Faculty Course Portfolios

This course portfolio documents the backward design of a senior-level design elective course in traffic engineering within the Department of Civil Engineering at the University of Nebraska. An extensive discussion of stakeholder needs for the course is followed by an analysis of formative and summative feedback assessments that are designed to meet the needs of a heterogeneous group of students in the course. As a senior-level design elective, there is a wide variety of interest levels among participants in the course, varying from those who have experience with internships in the topic and offer letters to conduct work in this …

In-Vehicle Evaluation Of Milled Rumble Strips At Pre- And Post-Chip Sealed Maintenance Periods, Ernest Tufuor, Laurence Rilett, Christopher Lefrois

Nebraska Department of Transportation: Research Reports

Driver fatigue and drowsiness can have a profound impact on safety. Centerline and shoulder rumble strips (RS) are popular countermeasures designed to produce audible and tactile warning when vehicles deviate from the travel lane onto the RS. This reduces the risk of lane departure crashes. Studies show that the noise produced by RS is a function of many variables. RS depth is known to have the greatest impact on alerting drivers. However, chip-seal pavement maintenance operations have the tendency to reduce the original RS design depth, which may have an impact on the functional effectiveness of the RS. The purpose …

Steel Pin And Hanger Assembly Replacement Options, Daniel Linzell, Chandana C. Balakrishna

Nebraska Department of Transportation: Research Reports

A number of steel beam bridges exist in the United States that contain pin and hanger assemblies. Pin and hanger assemblies are fracture critical members whose failure would result in collapse of the bridge or render it unable to perform its expected functions. As these bridges continue to age, many assemblies have deteriorated to a point where retrofit or replacement has to be considered and performed to maintain intended safety and performance. States have taken various approaches to address the pin and hanger assembly retrofit and replacement options. However, there is no single report that summarizes these approaches. This report …

Development Of A Test Level 3 Transition Between Guardrail And Portable Concrete Barriers, Robert W. Bielenberg, David Gutierrez, Ronald K. Faller, John D. Reid, Phil Tenhulzen

Department of Civil and Environmental Engineering: Faculty Publications

Road construction often requires that work zones be created and shielded by portable concrete barriers (PCBs) to protect workers and equipment from errant vehicles as well as to prevent motorists from striking other roadside hazards. For an existing W-beam guardrail system installed adjacent to the roadway and near the work zone, guardrail sections are removed so a PCB system can be placed. A study was done to develop a crashworthy transition between W-beam guardrail and PCB systems. Design concepts were developed and refined through computer simulation with LS-DYNA. Additionally, a study of critical impact points was conducted to determine impact …

Calibrating The Robertson’S Platoon Dispersion Model On A Coordinated Corridor With Advance Warning Flashers, Zhao Li, Laurence Rilett, Ernest Tufuor

Department of Civil and Environmental Engineering: Faculty Publications

Platoon dispersion (PD) is the foundation of traffic signal coordination in an urban traffic network. PD describes the phenomenon by which vehicles depart from an upstream intersection as a platoon and begin to disperse before they arrive at the downstream intersection. Recently, advance warning flashers (AWFs) have been applied in many high-speed corridors. There is a need to update the traditional PD model to include the effect of AWFs. This paper examines the traffic flow dispersion patterns when an AWF is present and tests the hypothesis that the AWF will affect PD on a coordinated signal corridor. Platoon vehicles, which …