An Examination and Recommendation for Current Practices in Roundabout Lighting

Abstract In 2000, the Federal Highway Administration (FHWA) and the American Association of State Highway and Transportation Officials (AASHTO) sponsored an international scan on the topic of roadway lighting. One of the topics covered in the international scan was roundabout lighting design practices. At the same time, the FHWA was actively promoting the use of roundabout intersections in the United States based on their safety and operational benefits. On return from the international scan, it was observed that there were a wide variety of practices with regard to roundabout lighting and that there was not a uniform understanding about what the recommended design practice should be. In response to this the Illuminating Engineering Society of North America (IESNA) Roadway Lighting Committee created a subcommittee to examine this issue and develop design guidelines for roundabout lighting. The authors of this paper are both members of the subcommittee. The current study was initiated in support of the IESNA effort in order gather information on the specific practices for lighting roundabouts in the United States and to obtain a better quantitative understanding of what constitutes a well lit roundabout in order to assist the IESNA in developing practical guidelines. The study evaluates the lighting at four roundabout sites with different levels of lighting and different lighting configurations. In addition to assessing general visibility criteria, the project examined overall roadway and pedestrian visibility. Various methods for collecting data are described and computer modeling results are presented

Bridge pier scour under pressure flow conditions

The probability of pressurized flow conditions occurring in existing bridges is forecast to increase due to possible changes in extreme precipitation, storm surges and flooding predicted under climate change scenarios. The presence of a pressure flow is generally associated with scouring processes in proximity to the bridge. Scouring can also occur around bridge piers, possibly causing infrastructure failure. While there is a vast literature on bridge pier scour and pressure flow scour, only a few studies have investigated their combined effect. This study will provide a new overview of the main features of bridge pier scour under pressurized flow conditions, based on laboratory experiences. Special focus is placed on the analysis of the flow features under pressure and free surface conditions and to the temporal evolution of the scour. A comparison with existing literature data is also conducted. The results highlight the nonlinear nature of scour processes and the need to consider pressurized flow conditions during structural design, as the interaction between pressure flow and the bridge pier strongly influences scour features and leads to scour depths much greater than the sum of the individual scours created only by pressure flow or pier presence

Fast Tracking as Standard Practice

In two short years, FHWA and MSHTO's Technology Implementation Group have sponsored 14 ACTT workshops, with more in the planning stage. Each attracts national transportation experts in specific skill sets who team up with colleagues from the host States to spotlight ways to shorten construction time, curb work zone congestion, and better serve motorists through improved quality. The workshops literally accelerate technology transfer by bringing innovative ideas to the table in concentrated two-day sessions. ACTT has cemented a track record of success in its workshops to date, according to participant feedback and results. Most agencies have found ways to slice construction time by 30 percent or more. Recurring recommendations have emerged: solutions with application to other highway projects across the States. The new approach to highway project development and construction is taking root as a standard practice. This second year report captures recommendations that have echoed through multiple workshops and distills the "best of" ACTT. It offers: recommended solutions by skill set and by project with a spotlight on those resonating through multiple State projects; benefits for participating State agencies; a look inside a workshop; the status of ACTT projects; phone numbers and e-mail addresses for experts; and an at-a-glance ACTT calendar of States and dates

Virginia Puts Award-Winning Plan Into Action to Improve Pedestrian Safety

The dispersed nature of pedestrian crashes often means that pedestrian safety countermeasures are installed in response to pedestrian crashes, rather than regularly installed in locations with factors that contribute to high pedestrian crash risk. The Virginia Department of Transportation (VDOT) combined hot spot and systemic analysis to proactively identify locations with high risk and known crash problems for their Pedestrian Safety Action Plan (PSAP). In 2020, VDOT updated the PSAP with more recent crash and risk factor datum generating new priority corridors and crash clusters

Need for Speed?

Vehicle speed is an important factor of roadway safety. Students will explore how speed is related to the design of a street and learn that travel speed is a decision made by drivers. Students will discover how a driver\u2019s ability to stop is related to human biology and principles of physics and how this translates into the distance needed for a driver to see a pedestrian and stop. Students will learn about these concepts by measuring their own reaction time then calculating laying out stopping distances given different conditions

Challenges and Opportunities for an ITS/Intermodal Freight Program

This brief describes a report on how operational tests could link public and private information and management systems, enabling terminal operators, freight carriers, and state and metropolitantraffic operations managers to share information to optimize flows and better utilizeequipment and facilities

Implementation Report of the USDOT Grade Crossing Safety Task Force

On March 1, 1996, the U.S. Department of Transportation (US DOT) Grade Crossing Safety Task Force delivered a report entitled Accidents That Shouldn't Happen to Transportation Secretary Federico Pena. Secretary Pena had directed that the Task Force be convened to address factors that might have contributed to a fatal collision involving a commuter train and a school bus in Fox River Grove, Illinois, in October 1995. In its report, the Task Force addressed safety problems that were not specifically covered in the Department's 1994 Rail-Highway Crossing Safety Action Plan: Interconnected Signals; Vehicle Storage Space; High-Profile Crossings; Light-Rail Transit Crossings; and Special Vehicle Operations. The report made 24 recommendations to remedy physical and procedural deficiencies in grade crossing construction, operation, maintenance, funding, enforcement, coordination, information, standards, and education. The principal finding of the Task Force report was that "improved highway-rail grade crossing safety depends upon better cooperation, communication, and education among responsible parties if accidents and fatalities are to be reduced significantly." With this in mind, the report proposed a status update: "The Task Force will reconvene one year after issuance of this report to evaluate progress in implementation of its recommendations." The Task Force fulfilled this recommendation on March 1, 1997, by delivering an interim report on the Department's progress to the Associate Deputy Secretary and Director of the Office of Intermodalism, Michael P. Huerta. The contents of this interim report have been incorporated as the first chapter of this document to give the reader a comprehensive overview of Departmental actions in implementing Task Force recommendations. The Task Force report proposed that "The FHWA will meet with the FRA to develop the process for implementing the FHWA long-term recommendation to convene a technical working group to evaluate current standards and guidelines for a variety of grade crossing technical issues. Selection of working group members and development of an implementation schedule should be accomplished by June 1, 1996, with the group's product targeted for completion by June 1, 1997 ." Among the noteworthy accomplishments of the USDOT Task Force are the convening of a Technical Working Group (TWG) that has made 35 recommendations for standards, guidelines and other grade crossing safety issues; the identification of focal points to coordinate railroad safety issues in each State; the initiation of regional State/railroad conferences; and the creation of an advance warning sign for motorists approaching high-profile crossings. All of the Task Force activities and accomplishments including the above are detailed in Chapter 1. Chapter 2 focuses on the accomplishments of the TWG. Among the noteworthy accomplishments of the TWG are development of uniform terms for railroad and traffic engineers; development of an interconnected warning placard for controller cabinets; and recommendations in the areas of interconnected signals, vehicle storage, joint inspections, and high-profile crossings. This report to Transportation Secretary Rodney E. Slater summarizes the technical working group's findings on improved standards and guidelines for railroad-highway grade crossing safety. In making this report, the Task Force reaffirms the Secretary's commitment to make transportation safety the Department's highest priority. The Department intends to distribute this report to all who participated in the TWG. By distributing this report, the Department urges those agencies, organizations, and other professional societies that participated in its compilation to take steps to formally endorse this report and implement its recommendations. The Department further recommends that the report's terminology for railroad-highway grade crossings be adopted and used as soon as possible in correspondence, training initiatives, and in new or revised railroad-highway grade crossing publications

Research Guides Countermeasure Selection in Boulder

The City of Boulder merged research and user-friendly tools to create guidelines that provide recommendations for pedestrian countermeasures at controlled and uncontrolled crossing locations