Engineering Commons^™

A Simple Method For Estimation Of Queue Length, S. P. Anusha, Lelitha Devi Vanajakshi, Anuj Sharma

Department of Civil and Environmental Engineering: Faculty Publications

Urban arterials are characterized by frequent intersections. Queue length and delay are the two primary measures of performance of intersection. These measures play a primary role in determining the arterial performance. This article presents a methodology to determine the number of vehicles in queue at a signalized intersection for under saturated traffic conditions. The results obtained were validated using actual values that are manually extracted. The root-mean-square error is of the range 1.3 vehicles for estimation of number of vehicles in queue. The various aspects that have to be considered in accurate estimation of performance measures are also discussed.

The Effect Of Skew Angle On Average Queue Delay At Tee-Intersections: A Simulation Study Using The Texas Model, Manogna Kaluva

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

This thesis explores the effect of intersection skew angle on average queue delay through simulation. The simulation model used is the TEXAS (Traffic Experimental and Analytical Simulation) model. This microscopic simulation model uses a general nonlinear car-following model. It simulates individual intersections and was designed to capture the interaction of traffic operations and intersection geometry.

Simulation models were developed for three stop-controlled, tee-intersections in Lincoln, Nebraska. Field data to develop and calibrate the simulation models were collected. All simulation models were calibrated by adjusting the car following parameters. An experimental design was developed to test the effect of skew angle …

Development Of A Field Test For Total Suspended Solids Analysis, Jessica Branigan

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

Total suspended solids (TSS) are all particles in water that will not pass through a glass fiber filter with a pore size less than 2 μm, including sediments, algae, nutrients, and metals. TSS is an important water quality parameter because of its adverse effects on aquatic species and wildlife. The EPA has proposed a regulation for turbidity, a related water quality parameter, which has been stayed pending further testing. TSS is regulated through the EPA via the NPDES in many states. Since there are no accepted field tests for TSS, projects with TSS regulations must send samples to a laboratory …

Passive Stormwater Samplers For Sampling Highway Runoff From Bmps: Feasibility Studies, Mitchell R. Klein

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

Pollution from highway stormwater runoff has been an increasing area of concern within the environmental field. To respond to the need for reduced contamination within runoff many Best Management Practices (BMPs) have been implemented. One difficult aspect of BMPs is monitoring their effectiveness along with determining effluent concentrations. The current methods for stormwater sampling include sending technicians or installing an auto-sampler to collect either grab or composite samples. These methods become costly, cumbersome and infeasible due to the potentially large amount of BMPs across a region and the irregularity and difficulty of predicting storms. Passive samplers have proven themselves as …

Driver Fatigue Enforcement Techniques And Their Effect On Crashes, Carrie Mohlman

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

Fatigued driving is a type of driver impairment caused by a lack of sleep, sleep disorders, long drive times, etc. Fatigued driving enforcement aims to improve safety by removing impaired drivers from the roadway. While fatigued driving is detrimental to safety, there exists the issue of identifying fatigue. There is a range between being awake and asleep and, in order to improve safety, enforcement officers must be able to identify the point at which drivers are impaired.

This thesis investigates potentially effective fatigued driving enforcement techniques for use by enforcement officers. These techniques were investigated through three primary means: a …

Velocity Measurements Of The Flow Over A Gate-Controlled Weir Structure, Mohamed M. Jalloh

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

The South Florida Water Management District (SFWMD) uses G304 control structures to manage flow into and out of a large storm-water treatment area (STA). These structures consist of a lateral unsuppressed weir, a sluice gate and a corrugated culvert for flow control and transfer through an embankment. For better flow control in the STAs, it is imperative to accurately measure the discharge through the G304 control structures and to determine the approach velocity over the weir for different field scenarios.

Flow behavior of the G304 structure was examined in a prototype during two days of testing for two canal headwater …

Structural Reliability Analysis Of Corroded Steel Girder Bridge, Mohammed S. Al Badran

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

The natural aging, environmental impact, and appropriate design are certainly playing a serious role in safety of the bridges function. The functional safety of bridge constitutes a prime element of the transportation system serving commuters, passengers and freight. According to Federal Highway Administration, the steel bridges share represents a large amount of the United States’ bridges. In last century, the collapse of both the Silver Bridge at Point Pleasant, WV over Ohio River on December 15, 1967 and over the Mianus River Bridge in Connecticut on June 28, 1983 showed that steel corrosion has been the leading reason in these …

Assessing The Impact Of Speed Limit Reduction Near Signalized High Speed Intersections Equipped With Advance Warning Flashers: A Case Study In Nebraska, Shefang Wang

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

This thesis evaluated the effects of 5 mph and 10 mph speed limit reductions in the vicinity of high-speed, signalized intersections equipped with Advance Warning Flashers (AWF). The selected methodology involved a field study of the impact of speed limit reduction at 7 high-speed, signalized intersections with AWF, using quantile regression models developed for speed. The quantile regression models for speed indicated that reduction of the speed limit from 60 mph to 55 mph did not have significant impact on observed speed during the green time. However, it was found that speed limit reduction from 65 mph to 55 mph …

Precast/Prestressed Concrete Truss-Girder For Roof Applications, Peter S. Samir

Department of Construction Engineering and Management: Dissertations, Theses, and Student Research

Steel trusses are the most popular system for supporting long span roofs in commercial buildings, such as warehouses and aircraft hangars. There are several advantages of steel trusses, such as lightweight, ease of handling and erection, and geometric flexibility. However, they have some drawbacks, such as high material and maintenance cost, and low fire resistance. In this paper, a precast concrete truss is proposed as an alternative to steel trusses for spans up to 160 ft. without intermediate supports. The proposed design is easy to produce and has lower construction and maintenance costs than steel trusses. The proposed design is …

Stormwater Pollution Treatment Bmp Discharge Structures, Miles F. Simmons

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

Structural best management practices (BMPs) are used to capture and treat stormwater runoff. Most structural BMPs provide treatment by filtering runoff through a filter media or collecting it in a detention basin and slowly discharging it over an extended period of time to allow suspended solids and associated contaminants to settle out. The purpose of this study is to design an effective outlet structure that provides adequate filtration or slows discharge to 40 hours.

A model detention basin was constructed in the Civil Engineering Hydraulics Laboratory at the University of Nebraska-Lincoln (UNL) and two full scale outlet structures were tested …

Precast Concrete Insulated Wall Panel Corbels Without Thermal Bridging, Mohamed Elkady

Department of Construction Engineering and Management: Dissertations, Theses, and Student Research

The common practice in corbel design is to block out the insulation in order to provide a solid concrete area at the corbel location. This connection practice results in thermal bridging, which significantly reduces the energy performance of the panel. For example, the PCI Design Handbook indicates that the reduction in thermal resistance caused by a solid part with an area equal to 9% of the total panel surface area is as high as 42%. This paper presents a discussion of a new concept for corbel design of insulated wall panels with the thermal break totally preserved. Two different designs …

Flow And Geometry Measurements At An Active Knickpoint, Clark W. Kephart

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

Channel degradation is an area of growing concern in areas of the Midwestern United States where there are large deposits of loess soils. Channel degradation occurs as a result of disturbances to the sediment load, bed soil configuration, and hydraulic characteristics of the stream (i.e. discharge, channel slope and geometry). These changes may occur suddenly or slowly over time. A given disturbance may be due to a large rain event, channel adjustments (i.e. dredging and straightening), and changes in land use around the stream (Chen et al. 1999).

A knickpoint is an abrupt drop in stream bed elevation over which …

Development Of A Field Test Method For Total Suspended Solids Analysis, Tian Zhang, John S. Stansbury, Jessica Branigan

Mid-America Transportation Center: Final Reports and Technical Briefs

Total suspended solids (TSS) are all particles in water that will not pass through a glass fiber filter with a pore size less than 2 μm, including sediments, algae, nutrients, and metals. TSS is an important water quality parameter because of its adverse effects on aquatic species and wildlife. TSS is regulated through the EPA via the NPDES in many states. Since there are no accepted field tests for TSS, projects with TSS regulations must send samples to a laboratory for analysis, which can delay projects for days or weeks. The goal of this research was to develop a rapid, …

Calibration Of Work Zone Impact Analysis Software For Missouri, Praveen Edara Ph.D., P.E., Ptoe, Carlos Sun Ph.D., P.E., Jd, Zhongyuan Zhu

Mid-America Transportation Center: Final Reports and Technical Briefs

This project calibrated two software programs used for estimating the traffic impacts of work zones. The WZ Spreadsheet and VISSIM programs were recommended in a previous study by the authors. The two programs were calibrated using field data from two work zones in Missouri. Both work zones involved a single lane closure on a three-lane section of roadway. The I-44 work zone was a long-term work zone, while the I-70 work zone was temporary, lasting only a few hours. The capacity values required for calibration were nearly identical for the two programs: 1,575 veh/hr/ln for the WZ Spreadsheet and 1,514 …

Evaluation Of J-Turn Intersection Design Performance In Missouri, Final Report, Praveen Edara Ph.D., P.E., Ptoe, Carlos Sun Ph.D., P.E., Jd, Sawyer Breslow

Mid-America Transportation Center: Final Reports and Technical Briefs

Research shows that a high percentage of crashes that take place on high-speed rural expressways occur at intersections with minor roads. One low-cost alternative design for improving the safety of at-grade intersections on such expressways is the J-turn. In the last few years, the Missouri Department of Transportation has converted some two-way stop controlled (TWSC) intersections into J-turns. This study evaluated the effectiveness of the J-turn intersection design in Missouri utilizing field studies, a public survey, crash analysis, and traffic conflict analysis. The field studies collected detailed video data at a J-turn site and a control site. The crash analysis …

Investigation Of Alternative Work Zone Merging Sign Configurations, Praveen Edara Ph.D., P.E., Ptoe, Zhongyuan Zhu, Carlos Sun Ph.D., P.E., Jd

Mid-America Transportation Center: Final Reports and Technical Briefs

This study investigated the effect of an alternative merge sign configuration within a freeway work zone. In this alternative configuration, the graphical lane closed sign from the MUTCD was compared with a MERGE/arrow sign on one side and a RIGHT LANE CLOSED sign on the other side. The study measured driver behavior characteristics including speeds and open lane occupancies. The measurements were taken at two identical work zones on I-70 in Missouri, one with the new test sign and the other with the standard MUTCD sign. The study found that the open lane occupancy upstream of the merge sign was …

Investigation Of Synergistic Effects Of Warm Mix Asphalt And High Fractionated Reclaimed Asphalt For Safe, Environmentally Sustainable Highway, Hosin David Lee Ph.D., P.E., Taha Ahmed Msc, E.I.

Mid-America Transportation Center: Final Reports and Technical Briefs

To increase RAP materials by up to 75% by binder replacement, a fractionation method was applied to the RAP stockpile by discarding RAP materials passing No. 16 sieve. This fractionation method was effective in improving volumetric properties of the HMA mixture with high RAP contents. The mix designs were then performed for both HMA and WMA with varying fractionated RAP amounts accounting for a replacement of 20, 30, 40, 50 and 75% of the mixture’s optimum asphalt binder content. All mix designs met the Iowa DOT mix design requirements except the one with 75% RAP materials by binder replacement due …

Towards Autonomous Vehicles, Chris Schwarz Ph.D., Geb Thomas Ph.D., Kory Nelson B.S, Michael Mccrary B.S., Nicholas Schlarmann, Matthew Powell

Mid-America Transportation Center: Final Reports and Technical Briefs

We are moving towards an age of autonomous vehicles. Cycles of innovation initiated in the public and private sectors have led one into another since the 1990s; and out of these efforts have sprung a variety of Advanced Driver Assistance Systems and several functioning autonomous vehicles. The challenges that face autonomous vehicle are still significant. There is still technical work to be done to make sensors, algorithms, control schemes, and intelligence more effective and more reliable. As automation in vehicles increases, the associated human factors challenges become more complex. Then, there are a host of socioeconomic issues. Are autonomous vehicles …

New Highway Accident Location Manual For Missouri, Carlos Sun Ph.D., P.E., Jd, Praveen Edara Ph.D., P.E., Ptoe, Henry Brown M.S., P.E.

Mid-America Transportation Center: Final Reports and Technical Briefs

The Missouri HAL manual is used to identify, analyze, and correct high crash locations, and has not been updated since 1999. This new edition brings the manual up to date, while incorporating the methodology of the national Highway Safety Manual (HSM). This 4th edition represents a complete re-working of all existing chapters of the manual. The changes are both stylistic and substantive. A contemporary book-style stylesheet was used to improve the appearance of figures, tables, headings, and labels. Even the title of the manual was changed from HAL (Identification, Analysis, and Correction of High-Crash Locations) to S-HAL (Safety Handbook for …

Development Of A Guide For Prioritization Of Railway Bridges For Repair And Replacement, Anna Maria Rakoczy, Andrzej S. Nowak

Mid-America Transportation Center: Final Reports and Technical Briefs

The objective of this study was to develop evaluation bases for the repair, rehabilitation, and replacement of existing railway bridges. Considering the importance of bridges to the railway network, the research involved the review and analysis of major factors that influence structural performance, e.g., degree of corrosion, loss of material (section loss, holes), fatigue problems, and loose connections. In particular, the research focused on connections, and their importance relative to the evaluation of bridge performance. The relationship between various conditions and the ability to perform the required function (i.e., carry a freight train) was established in the form of maximum …

Studying Platoon Dispersion Characteristics Under Heterogeneous Traffic In India, Jijo Mathew, Helen Thomas, Anuj Sharma, Lelitha Devi, Laurence Rilett

Department of Civil and Environmental Engineering: Faculty Publications

Platoons are created by signalized intersections which control travel patterns of vehicles. It is common for platoons to disperse during normal traffic operations. While platoon dispersion has been studied extensively under homogenous and lane disciplined traffic conditions, this characteristic under heterogeneous conditions has not been addressed adequately. This study will be one of the first steps in this direction and will lead to better understanding and simulation of platoon dispersion under Indian conditions.

Data describing platoon dispersion was collected with video recording systems along an arterial in Chennai, India. The Robertson’s model parameters calibrated for this data was found to …

Calibration Of The Highway Safety Manual For Missouri, Carlos Sun Ph.D., P.E., Jd, Henry Brown Msce, P.E., Praveen Edara Ph.D., P.E., Boris Carlos, Kyuongmin Andrew Nam

Mid-America Transportation Center: Final Reports and Technical Briefs

The new Highway Safety Manual (HSM) contains predictive models that need to be calibrated to local conditions. This calibration process requires detailed data types, such as crash frequencies, traffic volumes, geometrics, and land-use. The HSM does not document in detail techniques for gathering such data, since data systems vary significantly across states. The calibration process also requires certain decisions, such as the correct sampling approach, determination of the minimum segment length, the treatment of left-turn phasing, and the inclusion or exclusion of speed-change lane crashes. This report describes the challenges, practical solutions, and results from a statewide HSM calibration in …