Transportation Intelligence

Volume 5 Number 6

December 2007

Administration

Safety

Environment

Traffic Control

Feedback

Structures
Accelerated laboratory and field investigations of corrosion inhibiting systems for concrete bridges
Nine commercially available corrosion-inhibiting systems including concrete admixtures, reinforcing steel coatings, and/or concrete surface coatings/sealers for use in concrete structures, were evaluated in electrochemical cells and on bridge barrier walls by accelerated methods and actual field conditions. The laboratory investigation included the assessment of the effectiveness of corrosion inhibiting concrete admixtures and rebar coatings in delaying or reducing steel corrosion by measurements of chloride thresholds and corrosion rates. The field evaluation consisted of the measurements of half-cell potential and corrosion rate of the steel reinforcement of concrete barrier walls, which had specially designed rebar ladders embedded in the concrete with thin cover depths, in order to reduce the time needed for chlorides to reach the surface of the reinforcing steel. (NACE Northern Area Eastern Conference paper NRCC-50025, September 2007, 15 p.)

Pavements
Testing technique to maintain asphalt concrete within the visco-elastic response
This paper presents laboratory test response of a variety of hot mix asphalts mixes tested using a strain-controlled loading approach. The research was done to assess the proposed AASHTO TP62-03 test protocol under certain conditions and the possibility of high stress levels resulting in permanent deformations in test samples. Study results were used to assess the suitability of switching to the strain-control approach to effectively maintain analysis within the linear visco-elastic response. Dynamic moduli determined in the study were used to construct master curves that map variations in the material stiffness with changes in traffic speed and temperature condition. (National Research Council of Canada paper NRCC-49716, 3 June 2007, 6 p.)

Administration

Impact of Trucks on Arterial LOS (Level of Service)
Large trucks have considerably different size and performance characteristics than passenger cars. Consequently, these trucks can have a significant impact on traffic operations. It is therefore essential to properly account for this impact in the traffic operations analysis in order to reflect the operational quality of the roadway as accurately as possible. Signalized intersections are one roadway facility that can be particularly sensitive to the presence of commercial truck traffic. The most common method used for the analysis of signalized intersections is contained in the Highway Capacity Manual (HCM). To account for the presence of large trucks in the traffic stream, the HCM includes a Passenger Car Equivalency (PCE) value. In the current edition of the HCM, a PCE value of 2.0 is applied for all large trucks, with no distinction between different sizes of trucks. The primary objective of this research was to determine appropriate truck PCE values to apply for signalized intersection analysis. The development of the PCE values was based on the relative headway concept, as defined in the HCM. (Florida Department of Transportation Report Impact of Trucks on Arterial LOS and Freeway Work Zone Capacity - Part A, July 2007, 107 p.)

Metropolitan Travel Forecasting: Current Practice and Future Direction
The Transportation Research Board Committee for Determination of the State of the Practice in Metropolitan Area Travel Forecasting was tasked with assessing the state of the practice in travel demand forecasting and identifying shortcomings in travel forecasting models, obstacles to better practice, and actions needed to ensure the use of appropriate technical approaches. This report provides the requested assessment and recommendations for improvement and is designed for officials and policy makers who rely on the results of travel forecasting. Following a summary of the findings and recommendations, the report is presented in the following chapters: (1) Introduction; (2) Forecasting Metropolitan Travel; (3) Institutional Framework for Travel Demand Modeling; (4) Current State of the Practice; and (5) Shortcomings of Current Forecasting Processes. (Transportation Research Board Special Report 288, 2007, 147 p.)

Audit Stewardship and Oversight of Large and Innovatively Funded Projects in Europe
As transportation agencies undertake nontraditional, innovatively financed infrastructure projects, a concern among State and Federal managers is the effectiveness of the audit stewardship and oversight for these projects. The Federal Highway Administration, American Association of State Highway and Transportation Officials, and National Cooperative Highway Research Program sponsored a scanning study to document best practices used in England, France, Ireland, Portugal, and Spain in the stewardship and oversight of large, innovatively funded projects. The scan team observed that the terms of public-private partnership contracts have evolved as the European countries have gained experience in their use, and business models and evaluations have become an integral part of project selection and monitoring. To be effective, public sector project auditors in Europe need a range of skills, such as value engineering, business modeling, capital budgeting, and performance auditing. (US Federal Highway Administration Report FHWA-PL-07-001, March 2007, 60 p.)

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Safety

Model Minimum Inventory of Roadway Elements—MMIRE
Safety data provide the key to making sound decisions on the design and operation of roadways, but deficiencies in many States’ safety databases do not allow for good decisionmaking. The Federal Highway Administration, American Association of State Highway and Transportation Officials, and the National Cooperative Highway Research Program sponsored a scanning study of how agencies in the Netherlands, Germany, and Australia develop and use traffic safety information systems. That scan produced a report that included recommendations for advancing safety themes in the areas of strategy, efficiency, and utility. A recently completed follow-on effort recommended the development of a Model Minimum Inventory of Roadway Element (MMIRE) that would define the critical inventory and traffic data elements needed by State and local jurisdictions to meet current safety analysis needs and data needs arising from a new generation of safety analysis tools. This current report presents a proposed MMIRE and documents the development process, which included review of the proposed MMIRE elements in a workshop of safety data experts. A listing of high-priority and supplemental inventory and traffic elements are presented, along with proposed coding for each element. (US Federal Highway Administration report FHWA-HRT-07-046, August 2007, 81 p.)

Pedestrian Safety at Midblock Locations
This report examines two aspects of pedestrian safety at midblock locations. In Part I, the report assesses the role of crossing locations and light conditions in pedestrian injury severity through a multivariate regression analysis to control for many other factors that also may influence pedestrian injury severity. Crossing locations include midblock and intersections, and light conditions include daylight, dark with street lighting, and dark without street lighting. The report formulates a theoretical framework on the determinants of pedestrian injury severity, and specifies an empirical model accordingly. In Part II, the report proposes a set of guidelines for marking midblock crosswalks at uncontrolled locations along Florida's State Highway System through a comprehensive process. It describes the approach taken to developing these guidelines and summarizes the available evidence on the effect of crosswalk markings on pedestrian-vehicle collision risks. The report sets up a simple model of pedestrian-vehicle collision risks, uses this model to identify three mechanisms that help explain why crosswalk markings may lead to higher pedestrian-vehicle collision risks, and uses this model to identify engineering treatments to counter these mechanisms. (University of South Florida Center for Urban Transportation Research report, September 2006, 66 p.)

Reducing crossover accidents on Kansas highways using milled centerline rumble strips : final report
Some U.S. states have been using or experimenting with centerline rumble strips (CLRS). In most states that use them, they are used only on no-passing sections or curves. KDOT contracted with Kansas State University (KSU) to survey other states and summarize their experience and to develop a research design to evaluate KDOT test installations. KSU surveyed U.S. and Canadian provinces and found no serious negative problems with CLRS and recommended that they be field tested. KSU field tested several patterns of rumble strips, i.e., varying width and spacing. After selecting the best patterns, KDOT installed about 15 mi of two patterns of on the centerline of a two-lane state highway. Concurrently, the authors were contractors on an National Cooperative Highway Research Program (NCHRP) synthesis on U.S. and Canadian experience with CLRS. This K-TRAN report summarizes the findings of safety benefits and non-benefits from this nationwide survey. The overall conclusion of this study is that the safety benefits of CLRS outweigh some non-benefits and they are a viable, low-cost safety device for reducing cross over crashes on two-lane highways. (Kansas Department of Transportation Report K-TRAN: KSU-00-4, September 2006, 50 p.)

Development of a Safety Evaluation Procedure for Identifying High-Risk Signalized Intersections in the Virginia Department of Transportation's Northern Virginia District
This research was undertaken to develop an evaluation procedure to identify high-risk four-legged signalized intersections in VDOT’s Northern Virginia district by traffic movements and times of day. By using the developed procedure, traffic engineers are expected to be able to identify signalized intersections where the traffic crash occurrences under different traffic conditions for different times of day are more frequent than would normally be expected. (Virginia Transportation Research Council report VTRC 08-R1, September 2007, 80 p.)

Interchange Safety Analysis Tool (ISAT): User Manual
This User Manual describes the usage and operation of the spreadsheet-based Interchange Safety Analysis Tool (ISAT). ISAT provides design and safety engineers with an automated tool for assessing the safety effects of geometric design and traffic control features at an existing interchange and adjacent roadway network. ISAT can also be used to predict the safety performance of design alternatives for new interchanges and prior to reconstruction of existing interchanges. The primary outputs from an analysis include: the number of predicted crashes for the entire interchange area, the number of predicted crashes by interchange element type (i.e., mainline freeway segments, ramps, ramp terminals and intersections, and crossroad roadway segments), the number of predicted crashes by year, and the number of predicted crashes by collision type. (US Federal Highway Administration Report FHWA-HRT-07-045, June 2007, 108 p.)

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Environment

How to Apply the Concepts of Sustainable Development to Transport?
This report has been produced by Technical Committee C2.1. Sustainable Development and Road Transport and provides an analysis of "How to apply the concepts of Sustainable Development to Transport?" from the approaches implemented in a few cases - either policies, programmes or projects. These cases were considered to be illustrative, relevant or even exemplary in this regard and which could show both what can be achieved and also what can lead to situations of deadlock. This analysis of concrete cases involves four categories of examples: prior activities that aim to integrate the ideas of sustainable development within road infrastructure: the cases of Finges (Switzerland), the Kaga Route (Japan), the A45 Motorway (France) and the IC6, IC7, IC37 and IC12 itineraries network (Portugal); approaches which involve the implementation of transport policies in developing urban areas: the cases of Sapporo (Japan) and Lundby (Sweden); approaches which illustrate situations of deadlock arising from a failure to integrate the three areas covered by sustainable development: the road crossing of the "Golestan Jungle" in Iran, the case of the N2 Wild Coast Road in South Africa, the case of the Via Baltica motorway in Poland; the implementation of road policies in developing countries: the case of Guinea Bissau (transborder road project), Angola (rehabilitation of the Lubango region road network) and the Cape Verde Islands (rehabilitation of the roads on five islands). (PIARC Report 2007R08, 2007, 65 p.)

Transportation and Global Warming: Defining the Connection and the Solution
While greenhouse gas (GHG) emissions grew by 20 percent in the United States over the last decade, they increased by 26 percent in Wisconsin. Recognizing global warming as a significant threat to Wisconsin’s economy and environment, Gov. Jim Doyle recently signed an executive order creating a Task Force on Global Warming that will bring together business, industry, government, energy and environmental leaders to develop global warming solutions for the state. Wisconsin DOT has been invited to be part of the Transportation Sector Working Group that will provide recommendations to the Task Force. In preparation, the WisDOT delegate wanted to locate information on the following topics: 1. transportation’s role in global warming (or climate change), and 2. potential solutions or mitigation measures that are transportation-related (both solutions that states have adopted and those under consideration). (Wisconsin Department of Transportation - Research and Library Services Unit - Transportation Synthesis Report, 16 July 2007, 81 p.)

The First State of the Carbon Cycle Report (SOCCR): The North American Carbon Budget and Implications for the Global Carbon Cycle
This report—CCSP SAP 2.2—addresses Goal 2 of the Climate Change Science Program (CCSP) Strategic Plan: Improve quantification of the forces bringing about changes in the Earth’s climate and related systems. The report provides a synthesis and integration of the current knowledge of the North American carbon budget and its context within the global carbon cycle. In a format useful to decision makers, it (1) summarizes our knowledge of carbon cycle properties and changes relevant to the contributions of and impacts upon North America and the rest of the world, and (2) provides scientific information for decision support focused on key issues for carbon management and policy. Consequently, this report is aimed at both the decision- maker audience and to the expert scientific and stakeholder communities. (United States Climate Change Science Program report, November 2007, 264 p.)

Environmental benefits of life cycle design of concrete bridges
This paper presents a life cycle-based approach for the design of concrete highway bridges that takes into account physical, economic and environmental performance with emphasis on the reduction of greenhouse gas emissions, construction waste production, and life cycle cost. The analysis considers all the key stages in the life cycle, which include extraction of raw materials, construction, maintenance, repair, rehabilitation, replacement, and disposal. The life cycle analysis compares the life-cycle performance of two concrete highway bridge decks built in corrosive environments – normal concrete is used for one and high performance concrete for the other. (National Research Council of Canada report NRCC-49675, 27 August 2007, 6 p.)

Integration of noise in PM systems - Pavement management and noise
Noise abatement is being an increasing challenge for the European road administrations. Cost effective solutions are needed in order to fulfil the requirements for good living conditions for the people living as neighbours to the road infrastructure. One promising approach can be to integrate noise abatement considerations and solutions in the ongoing process of maintaining the road infrastructure . Pavement management systems are often used as an effective tool in the planning of maintenance of the road networks. Therefore it is an obvious challenge to integrate noise considerations in pavement management systems in an operational and effective way. On this background the EU project SILENCE started in February 2005 also includes a Task F3 focusing on this subject. The title of this Task is: “Improved systems for maintenance of quieter surfaces." In this report noise-related parameters of existing pavement monitoring systems are presented and evaluated and the possibilities of integrating acoustic parameters in pavement management systems are discussed. (Danish Road Institute Report 150, 2007, 52 p.)

Calcul des charges de pollution chronique des eaux de ruissellement issues des plates-formes routières (Computation of chronic pollution loads in roadbed run-offs)
The goal of this briefing is to present report progress on several years of studies focused on the qualification and quantification of chronic pollution related to road traffic. It rounds up acquired knowledge in the field of roadway pollution and it proposes computation methods to estimate pollution loads. The briefing results from the actual application of measures developed during the 1995-1998 period. At each site, monitoring duration was about one year. The briefing is meant to provide a common, simple and up-to-date basic understanding of the subject matter to road project developers and also to instruction services responsible for multi-water services tasks involving the preparation of files related to the Water Act. (Service d'Études techniques des routes et autoroutes (Setra) note d'information 75, juillet 2006, 12 p.)

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Traffic Control

2007 National Traffic Signal Report Card
The National Transportation Operations Coalition (NTOC) has released the 2007 National Traffic Signal Report Card. According to NTOC, the report card shows how local jurisdictions such as cities, counties, and states can reap large rewards, such as mitigating congestion and lessening fuel consumption, by making small changes in the way they manage and operate their traffic signal systems. The report also highlights several jurisdictions that have been successful in making changes since the 2005 report card was released. The results contained in the report card are based on the 2007 Traffic Signal Operation Self-Assessment released by NTOC in the fall of 2006. A total of 417 agencies responded, representing 47 states. Organizations involved in NTOC include the U.S. Federal Highway Administration, the U.S. Federal Transit Administration, the American Association of State Highway and Transportation Officials, the Institute of Transportation Engineers, the American Public Transportation Association, and TRB. (National Transportation Operations Coalition technical report, 2007, 61 p.)

Effectiveness of "Children at Play" Warning Signs
WisDOT is engaged in an effort to reevaluate and update its policies regarding roadside warning signs related to children, such as “Children at Play,” “Blind Child,” “Deaf Child,” etc. We were asked to review research on the effectiveness of these types of signs to better ground WisDOT’s policy decision. (Wisconsin Department of Transportation Research and Library Unit Transportation Synthesis Report, 25 September, 2007, 6 p.)

Updates to Research on Recommended Minimum Levels for Pavement Marking Retroreflectivity to Meet Driver Night Visibility Needs
This study was aimed at completing the research to develop and scrutinize minimum levels for pavement marking retroreflectivity to meet nighttime driving needs. A previous study carried out in the 1990s was based on the CARVE model developed at Ohio University and resulted in a table of minimum levels of pavement marking retroreflectiviy values. Since then, a newer, more powerful analytical tool, Tarvip, which was developed at the Operator Performance Lab of the University of Iowa, overcomes a lot of limitations of the CARVE model and uses updated data that reflect the current states of vehicles and roadways in the United States. (US Federal Highway Administration Report FHWA-HRT-07-059, October 2007, 46 p.)

Assessment of Traffic Control Practices with Respect to Older Drivers
When signage on a rural highway in Kansas was upgraded, the State received some comments that begged the question of whether modern highly reflective sign sheeting materials could, in some circumstances, actually decrease the legibility of signage, particularly for older drivers. Older drivers tend to have poorer visual acuity, requiring larger signs to provide the same legibility as found in a younger population. However, older drivers also tend to be more sensitive to glare and slower to recover from glare blindness. This study was conducted to determine if highly reflective sheeting could cause a reduction in sign legibility due to veiling glare, especially in older drivers. The test was conducted using 60 drivers in an actual automobile and full scale signs and distances. The data collection was conducted in a test facility where external factors could be eliminated, isolating the variables of greatest interest. Older drivers as a whole were found to exhibit poorer performance in terms of visual acuity and response time, but no detrimental effects attributable to glare were observed. (Kansas Department of Transportation Report K-TRAN: KU-01-04, July 2007, 72 p.)

Assessment of Channelizing Device Effectiveness on High-Speed/High-Volume Roadways
Recent editions of the MUTCD have introduced new devices for channelizing; specifically of interest for this study is a taller (>36 inches) but thinner cone. While this new device does not offer a comparable target value to that of drums, the new devices are significantly larger than standard cones and they offer improved stability as well. An investigation of the effectiveness of the new channelizing devices provides a reference for states to use in selecting appropriate traffic control for high speed, high volume applications, especially for short term or limited duration exposures. This study includes a synthesis of common practices by state DOTs, as well as daytime and nighttime field observations of driver reactions using video detection equipment. The results of this study are promising for the day and night performance of the new tall cones, comparing favorably to the performance of drums when used for channelizing in tapers. (Iowa State University Center for Transportation Research and Education Project 06-278, July 2007, 66 p.)

VMS - Variable Message Signs: A Literature Review
This literature review is primarily aimed at describing studies that deal with the interaction between driver behaviour and variable message signs, VMS. The collected references are, for the most part, published in Europe or studies about European conditions, published between the years of 2000-2005. (Swedish National Road and Transport Research Institute (VTI) Report 570A, 2007, 55 p.)

Automated Enforcement: A Compendium of Worldwide Evaluations of Results
This compendium details automated enforcement systems (AES) implemented around the world and characterizes the safety impacts of such deployments, based on available scientific evaluations of the outcome measures. A systematic literature search was conducted. Criteria for selecting key evaluation studies were developed and applied for two AES technologies: speed camera and red light camera (RLC) enforcement systems. (US National Highway Traffic Safety Administration report, July 2007, 136 p.)

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