William Rasdorf

The purpose of this research is to add new insights regarding the benefits and drawbacks of using intersections with three-phase traffic signals compared to other intersection designs and to develop a technical guideline to help designers and policymakers in transportation understand when and where to use three-phase designs. At four-phase conventional intersections where traffic demand is near or above capacity, innovative intersections may perform better. New designs with two-phase traffic signals such as reduced conflict intersections (RCI, also called RCUT and superstreet) result in shorter travel times, fewer crashes, and better pedestrian service in North Carolina (NC). However, retrofits to designs with two-phase signals may be impactful and unpopular. Higher minor street demand, lack of precedent, and complaints (from neighbors, business owners, politicians, media, etc.) are among the possible obstacles for constructing two-phase designs in many locations. In other words, while two-phase intersections perform very well at many intersections, designers might not be able to select those designs for some projects. On the other hand, intersections with three-phase signals might provide some of the two-phase design advantages while also providing more direct movements and alleviating some public concerns. This study seeks to answer the following questions: (1) At what locations are three-phase designs most well suited? (2) How much do they cost, especially compared with other intersections like RCIs? (3) What kind of traffic control devices (pavement markings, traffic signs, and traffic signals) are needed? (4) What movement restrictions could cause motorist confusion and violations? (5) How could we minimize those violations? (6) What are the considerations needed for pedestrian and bicyclist safety? (7) What kind of geometric and right-of-way (ROW) limitations are faced during construction? (8) What movements are less impactful for redirecting in different cases? (9) What designs would be most readily accepted by the public? Current literature on innovative intersections with three-phase signals is limited. Excluding offset, partial continuous-flow intersections (CFIs), and quadrant intersections, (three common three-phase designs in NC) little information is available on the performance of other three-phase intersections. Reviewing the Crash Modification Factors (CMF) Clearinghouse reveals that only a few studies have estimated CMFs for converting four-phase conventional intersections to three-phase intersections. These studies focused on partial CFIs and partial median U-turn intersections (MUTs). Other possible three-phase designs should also be evaluated to increase the confidence level in selecting the most appropriate design. A recent presentation by NCDOT????????s Dr. Joseph Hummer introduced ten three-phase intersections as possible candidates for future projects. Based on initial evaluations, the ten three-phase designs could show potential in improving existing intersections. The research team also proposes another new three-phase design which could be considered as a promising design. The proposed three-phase intersection redirects two left-turn and one through movements. It is expected to experience higher capacity for the proposed design compared to conventional intersection due to better signal progression and a lower volume to capacity (v/c) ratio. Also, the proposed design has 19 conflict points. Only two of the existing three-phase designs (reverse RCI and offset intersections) have fewer conflict points compared to the proposed design. This proposed study focuses on the following three-phase designs: partial MUTs, partial CFIs, reverse RCIs, thru- cuts, offset, quadrant, CFI/MUT combo, redirect one minor leg, redirect minor lefts, seven-phase signal, and redirect two lefts and a through intersection (see Figure 1 in the body of the proposal). Also, the research team will consider other new designs, especially where another proposed design might perf

The purpose of this research is to assess NCDOT traffic signal maintenance procedures and signal replacement cycle to benchmark their costs so that signal performance is maintained or enhanced and to develop a model for LED powered signal life span. This study answers the question ????????????????what is the threshold at which an acceptable working LED traffic signal is in need of replacement???????????????? This study will explore whether or not a systematic signal replacement strategy could be developed and used by any division within NC to enhance performance, reduce waste, reduce cost, and be realistically and efficiently implemented.

Alternative Intersection and Interchange (AII) designs are those which provide an innovative approach to the geometric or control features which may improve operations and/or safety for different road users. In 2010, the U.S. Federal Highway Administration (FHWA) published the first edition of ????????????????Alternative Intersection and Interchange Informational Report??????????????? (AIIR), which provided information on six alternative treatments including displaced left-turn (DLT) intersections, restricted crossing U-turn (RCUT) intersections, median U-turn (MUT) intersections, quadrant roadway (QR) intersections, double crossover diamond (DCD) interchanges, and DLT interchanges. For each treatment, AIIR presented detailed information in a standardized format, including salient geometric design features, operational and safety issues, access management, costs, construction sequencing, environmental benefits, and applicability. The AIIR first edition has been employed by various agencies as a valuable resource for planning and designing AIIs, there are still unconventional design concepts that have not been fully explored and some of the current ones could use updates. During the past decade, there have been an increasing number of AIIs installed in the United States, and more new AII designs that are not documented in AIIR first edition have emerged since 2010, such as Reverse RCUTs, Partial Median U-turns, and Grade-Separated Alternative Intersections, etc. These new AII designs may involve different traffic organization patterns, which may introduce confusion and create safety hazards for drivers. NCDOT is a national leader in AII implementation, which provides safe, efficient, and cost-effective travel solutions for North Carolina drivers. Therefore, the primary objective of this research is to start the process of compiling the AIIR Second Edition. Specifically, this research will provide a state-of-the-practice literature review and expert interviews on AII designs, draft an annotated outline for the AIIR second edition, and develop an updated set of simulation models to assess the performance of various AII designs. Finally, this research will provide practical recommendations for planners and engineers to select site-specific AII designs during project processes.

The purpose of this research is to assist the NCDOT Traffic Management Unit (TMU) and the Value Management Office (VMO) in assessing issues regarding the construction of Diverse, Modern, and Unconventional Intersections and Interchanges (DMUII). Assessing the constructability of these emerging DMUII is a new area of study that has not yet been previously explored. Therefore, this research will identify factors affecting construction projects prior to construction and develop a schedule and cost payout model (based on prior NCDOT projects) that identifies problems related to expenditure, schedule, and obstruction of traffic during construction.

The North Carolina State Institute, in its role as subcontractor to East Carolina University, will perform a total of $109,639 in contracted work from the period of August 2019 to July 2021. 1. Task 1. Kickoff Meeting. NC State will assist with the identification and scope of the research project. In addition, NC State will assist in the presentation of the data collection plan, methodologies for data analysis, and final products, as directed by ECU. 2. Task 2. Develop Literature Review on Best Practices. For this task, NC State will work collaboratively with ECU in the development of the literature review concerning best practices for conducting the constructability review process. Where appropriate, NC State will provide the relevant expertise and guidance. 3. Task 3. Schedule Stakeholder Meetings and Attend Constructability Review Meetings. will work collaboratively with ECU to schedule phone interviews with relevant stakeholders, focusing on those who have participated in previous constructability review meetings. In addition, NC State will lead the development of a comprehensive database of concerns raised by various project stakeholders (e.g., project owner, design engineers, general contractors, etc.) 4. Task 4. Refine Review Process and Establish Metrics. For this task, NC State will assist ECU in the development of constructability metrics and, where appropriate, establish new metrics for review. NC State will assist in the presentation of findings and metric recommendations to NCDOT. 5. Task 5. Develop Tracking Methods/Benefits Assessment Methodology and Tool. NC State will assist in the development of the tool methodology and action plan; NC State will lead in the database development. Finally, NC State will assist in the development of the draft constructability review tool which will be provided to NCDOT Value Management Office staff. 6. Task 6. Development of Action Plan and Spreadsheet Tool. NC State will assist in the refinement and development of the final constructability review tool to NCDOT staff. In addition, NC State will assist ECU in providing a final action plan report (with recommendations) to NCDOT.

Recent advances in small unmanned aerial systems (UASs) and sensing technologies have enabled relatively low cost and effective surveying methods for preconstruction, construction, and slope sites. However, the commercial software that accompanies these technologies produces inconsistent and unreliable survey results and there are no guidelines for ensuring the quality of the data. Without proper guidelines and specifications, repeated surveying at a designated area over time (e.g., construction site with periodic data collection) is not ideal.

Individual students applied for the DDETFP Fellowship. The selected student, their faculty advisor or campus program manager, and the institution 6 (????????????????Recipient???????????????) will be responsible for completing and submitting all required paperwork to execute the fellowship. Funding will be sent to the Recipient on behalf of the Student Designee. The Recipient will be responsible for allocating funds to the student as outlined in the Budget of this Agreement. The Recipient will also be responsible for submitting all required reports to FHWA.

The Powell Bill Unit of the NCDOT annually distributes a fixed appropriation from the State Highway Fund to qualified North Carolina municipalities to maintain municipal streets within their corporate limits. The eligible activities covered by the funds include construction, planning, and maintenance on streets, sidewalks, bikeways, and greenways such as resurfacing, patching, widening, storm drainage, curb and gutter, and patching. It can also be used for municipal street bond debt service and traffic control such as traffic control devices, traffic signs, speed bumps, traffic paint, and traffic cones.

The purpose of this research is to assess alternate NCDOT roadway sign replacement strategies and to benchmark their costs so that sign performance is maintained or enhanced while lowering costs. This study answers the question ????????????????is there an implementable lower cost sign replacement strategy that meets or exceeds current performance levels???????????????? This study will explore whether or not this strategy could consist of a systematic sign replacement strategy that can be used by any division within North Carolina.

Asset management is a relatively new concept in geotechnical engineering. In general, the nature of earth structures within the realm of highway engineering renders the concept of asset management a valuable tool for operation efficiency and cost control. Asset management includes a database of assets, tools to manage the database, asset condition assessment models, and strategies for assessment, mitigation, rehabilitation, and replacement. At present, there is no systematic tool to provide electronic documentation and analysis of earth structures including the retaining wall inventory maintained by the North Carolina Department of Transportation (NCDOT). The objective of this research is to design and develop a database archival and retrieval system for electronic documentation, management, qualitative analysis, and display of retaining walls, especially critical walls such as those adjacent to bridges. Such structures include MSE, soil-nail, tie-back, gravity, cantilever, and pile panel walls. The prototype database to be created will include wall location, geometry, internal configuration, local geology, and external signs of stress such as tilt and cracking. The development of rating criteria models that are specific to particular wall types will also be explored in consultation with NCDOT. The development of a systematic means for cataloging and condition assessment of highway retaining structures will represent a major contribution to the ability to establish effective and sustainable maintenance and replacement priorities. The primary project product is referred to herein as a database and includes a definition of all data tables and the attributes they contain. The final report will provide these definitions as well as sample data for 12 existing retaining walls populating all tables. Data collection procedures will include both wall spatial as well as wall attribute (characteristics) data. The spatial data will be organized in such a way as to be able to link to existing NCDOT systems. The proposed database (of key parameters defining the various types of retaining walls within the state) is intended to assist NCDOT engineers and contractors in evaluating the need for maintenance and replacement as well as capture often-lost assets for effective master planning, engineering, design, maintenance, and management of highway retaining structures.