Transportation Intelligence

Volume 3 Number 2

April 2005

Traffic Management

Structures

Pavements

Planning

Environment

Administration

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Pavements
Edge Cracking in Hot Mix Asphalt Pavements
The purpose of this research is to determine the probable cause or causes of edge cracking in asphalt pavements in Colorado. Edge cracking has been an asphalt pavement failure mechanism in Colorado for many years. When edge cracking began and how widespread the phenomenon is difficult to determine. This is because the problem seems to be limited to private construction projects in subdivisions and parking lots rather than public pavements constructed by the DOT. (Colorado Asphalt Pavement Association, 2005, 43 p.)

Structures
Guidelines for the Installation, Inspection, Maintenance and Repair of Structural Supports for Highway Signs, Luminaries, and Traffic Signals
This document provides guidance for the installation, inspection, maintenance, and repair of structural supports for highway signs, luminaries and traffic signals. The primary purpose is to provide owners with information that can assist them in managing their inventory, identifying potential problem areas, and ensuring safe and satisfactory performance of these types of ancillary highway structures. The primary reason for compiling this guidance is increasing problems with wind induced vibration, fatigue, and even structural collapse of these support systems. (Federal Highways Administration, 145 p.)

Traffic Management
Stops and Goes of Traffic Signals - A Traffic Auditor's Perspective
Transfund has been assisting the traffic signal industry to increase its capability in design, construction, operation and maintenance of traffic signal installations. One of the components of this assistance has been to facilitate the development of an audit methodology for existing installations. Transfund has commissioned audits of eight local authorities’ installations. Other authorities have commissioned their own audits. This booklet summarises the findings of the audit reports. Its purpose is to assist and advise practitioners. (Transfund New Zealand report, November 2004, 24 p.)

Traffic Management

Work Zones That Work
The public's frustration with work zones is evident from the results of a 2000 nationwide survey report by FHWA titled Moving Ahead: The American Public Speaks on Roadways and Transportation in Communities. The report cited work zones as second only to poor traffic flow in causing dissatisfaction. Statistics show that work zones, in addition to causing delay, can be dangerous for construction crews and motorists. Work zone fatalities increased nationwide by 17 percent over the last 5 years. (Public Roads, November/December 2003, pp 22-29.)

Telecommunications Handbook for Transportation Professionals - The Basics of Telecommunications
This handbook was created to provide individuals responsible for managing and implementing Traffic Signal, and Freeway Management programs with an understanding of the basic technologies of telecommunications. The handbook provides a brief look at the history of telecommunications so that its readers may gain an understanding of why various processes exist, and how the technologies evolved. The handbook is not designed to be used as a specification for telecommunication systems. (Federal Highways Administration report FHWA-HOP_04-034, August 2004, 288 p.)

Red Light Camera Systems - Operational Guidelines
The purpose of these guidelines is to assist jurisdictions who are considering the implementation of red light camera systems and help them avoid inconsistent or incorrect application of such systems. Questions have been raised regarding the contracting, design, implementation, operation of red light camera systems, and the legality and intent of photo enforcement systems. In a broader perspective, for continued use of red light camera systems and other technologies to improve transportation operations and safety, it is vital these technologies are perceived as accurate and reliable and are applied fairly. (Federal Highway Administration/National Highway Traffic Safety Administration report, 2005, 59 p.)

Development of Guidelines for the Installation of Marked Crosswalks
The purpose of this research was to develop guidelines for the installation of marked crosswalks that the Virginia Department of Transportation (VDOT) could use statewide. The scope of the research was limited to a review of the literature on marking crosswalks. The author postulated that the information found in the literature could be used to develop guidelines acceptable to VDOT, thus saving an extensive and costly field-based research effort. (Virginia Transportation Research Council Report 05-R18, December 2004, 47 p.)

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Structures

Evaluation of FRP Repair Method for Cracked Bridge Members
This research program was undertaken to investigate the effects Carbon Fiber Reinforced Polymers (CFRP) have on the shear strength on under-reinforced, lab-scale prestressed concrete (PC) bridge girders. (Missouri Department of Transportation Report RTD04-024, 2005, 68 p.)

Evaluation of Two Corrosion Inhibitors Using Two Surface Application Methods for Reinforced Concrete Structures
This study investigated the use of penetrating corrosion inhibitors to extend the life of existing reinforced concrete bridge decks. The use of assisted (vacuum/pressure injection) and unassisted (diffusion) treatment methods and two inhibitors were evaluated. The inhibitors were FerroGard 903, from Sika Corp., and TPS-II, from Surtreat International. (Virginia Transportation Research Council Report VTRC 05-R16, 2004, 31 p.)

Assessing the load carrying capacity of timber bridges using dynamic methods
A reliable determination of the structural condition of timber bridges presently requires costly load testing. A new testing method is described which has recently been used to undertake field-testing of more than 20 timber bridges across NSW. The bridge assessment procedure involves the attachment of accelerometers underneath the bridge girders. The vibration response and natural frequency of the bridge superstructure is measured when a “calibrated sledgehammer” is used to hit the unloaded deck, and then again with a relatively small mass applied at mid-span. The difference in response allows load carrying capacity of the bridge to then be calculated. (Institute of Public Works Engineering Australia report, 10 p.)

Evaluation of Guardrail to Concrete Bridge Rail Transitions
In December 2001, the Design Division and Bridge Division of Texas Department of Transportation released a new standard for an approach guard fence to concrete bridge rail transition that complies with the testing requirements of National Cooperative Highway Research Program (NCHRP) Report 350 for use on high-speed roadways. Because there are no national transition designs that have been developed and tested for lower speed conditions, the same transition standard is typically applied to all roadways regardless of speed. The purpose of this research was to develop a transition that is suitable for use on lower speed roadways and that is less expensive and complex than the current high-speed design. A low-cost transition was successfully evaluated at 45 mph impact speeds under NCHRP Report 350 Test Level 2 conditions. (Texas Transportation Institute Report FHWA/TX-04/4564-1, 2003, 88 p.)

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Pavements

Bituminous crack sealants in Canada: research and performance specifications
Twelve bituminous sealants were installed and their performance monitored. Performance did not correlate to standard test result. This was related to the effect of installation on performance and to an inappropriate material specification. Installation issues were addressed by the publication of the state-of-the-art practice. Specification issues are being addressed by the development of performance specifications that account for sealant aging, rheology, and adhesion. (National Research Council IRC paper NRCC-47641, February 2005, 4 p.)

Potential Applications of Paving Fabrics to Reduce Reflective Cracking
The Mississippi Department of Transportation’s Research Division has released a report produced by the Jackson State University Department of Civil and Environmental Engineering that synthesizes available literature on the applications and effectiveness of stress-relieving interlayers, known as paving fabrics, to reflective cracking. The report also examines basic functions of paving fabrics, fabric specifications, mechanism, long-term performance, life cycles and cost effectiveness, factors influencing performance, recent innovations, and lessons learned from installation. (Mississippi Department of Transportation report FHWA/MS-DOT-RD-05-174, February 2005, 45 p.)

Using Gyratory Compactor to Measure Mechanical Stability of Asphalt Mixtures
In this study several asphalt mixtures were produced using four different aggregate sources, different asphalt contents, and different aggregate gradations. Every mixture was compacted using the Superpave Gyratory Compactor (SGC). The purpose of this study was to use the gyratory compactor as an indicator of the mechanical stability of the asphalt mixtures. The goal of the project was to identify and suggest limits to be used as screening criterion to select mixture for various traffic levels. (Wisconsin Department of Transportation Report WHRP 05-02, October 2004, 95 p.)

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Planning

Truck Trip Data Collection Methods
A considerable body of research exists for addressing the data needs for passenger transportation models and statewide freight truck movements. The number of studies which focus on methods for capturing the necessary data on urban freight movements is less abundant. This study addresses this problem by identifying those freight data attributes necessary for both urban region truck modeling and freight planning efforts and evaluates alternative data collection methodologies for providing these necessary data attributes. (Oregon Department of Transportation Report FHWA-OR-04-10, February 2004, 111 p.)

Evaluation of Different Methods to Calculate Heavy-Truck VMT
Reliable estimates of heavy-truck volumes are important in a number of transportation applications. This research evaluated three different methods to calculate heavy-truck annual average daily traffic (AADT) which can subsequently be used to estimate vehicle miles traveled (VMT). (MidWest Transportation Consortium Report 2002-02, December 2004, 64 p.)

Developing a Sketch-Planning Technique Relating Economic Activity and Urban Mobility in Small and Medium-Sized Urban Areas
Traffic congestion continues to be a growing problem for cities of all sizes in the United States. Transportation agencies in urban areas are facing the difficult challenges of providing an efficient and reliable transportation system for residents and businesses despite ever-diminishing resources. This research uses readily available socio-economic, land use, and traffic congestion data from many of the Texas urban areas to create prediction models to estimate future traffic congestion levels. (Southwest Region University Transportation Center report SWRUTC/04/167703-1, August 2004, 365 p.)

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Environment

Recommendations for Winter Traction Materials Management on Roadways Adjacent to Bodies of Water
Wherever possible, a combination of both structural and non-structural BMPs, or best management practices, should be employed to minimize the environmental impacts of winter traction materials. This report focuses on the cold region and rural transportation perspective, and discusses the structural BMPs potentially applicable in Montana in greater detail, including the applicability, site criteria, engineering characteristics, safety concerns, maintenance issues, costs, effectiveness in the presence of snow, and sediment removal efficiency. (Montana Department of Transportation Report FHWA/MT-04-008/8117-19, December 2004, 97 p.)

Review of Water Movement in the Highway Environment: Implications for Recycled Materials Use
Significant amounts of recycled materials are being used in structural components of highways such as base, subbase, Portland cement and asphalt concrete, and embankments. Past experience with recycled materials in highways has not shown a risk with respect to environmental impact and human health. However, environmental regulatory agencies frequently must assess risk to human health and the environment when conducting beneficial use determinations, particularly for new recycled materials. The purpose of this study was to describe the state of the knowledge about water movement in the highway environment so that this knowledge may be incorporated into (1) practical leaching and preliminary impact assessments and (2) fate/transport models for use in risk assessment. (Recycled Materials Resource Center, University of New Hampshire report, February 2002, 112 p.)

The Effect of Novel Soil Amendments on Roadside Establishment of Cover Crop and Native Prairie Plant Species
The re-establishment of native plant species has been a principle objective of managers of roadside vegetation for many years. However, the establishment of native species, especially on the near inslope of roadsides has always been problematic. Soils of inslopes are generally nutrient poor, lack organic matter, and experience extreme microclimates of heat and nearly continuous drought. This report examined the concept that application of amendments to the soil or over the soil might have the capacity to increase fertility, increase soil moisture, or moderate the harsh microclimate of the inslope. In this study three different soil amendments/treatments were used to modify inslope soils including application of erosion control materials (ECMs) and enhancing soils with organic material. (Minnesota Department of Transportation report 2004-41, September 2004, 78 p.)

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Administration

Growing Traffic in Rural America: Safety, Mobility and Economic Challenges in America's Heartland
Main Report; Appendix A; Appendix B
This report looks at the condition, use and safety of the nation’s non-Interstate rural roads, based partly on a new analysis of all fatal rural traffic accidents over the five year period from 1999 to 2003. Rural Interstate routes were excluded from the safety analysis in this report because they are built to very high safety standards, and do not have the significant traffic safety problems common on many rural roads. The report also looks at steps some states are taking to improve rural traffic safety and concludes with recommendations to reduce traffic fatalities on the nation’s rural roads. (The Road Information Program (TRIP) Report, March 2005, 31 p.)

Elements of a Comprehensive Signals Asset Management System
This document takes an initial step towards development of an operations asset management methodology through an investigation of traffic signal systems applications. It presents findings of a state-of-the-practice review of signal systems asset management and lays out the characteristics of signal systems that need to be considered in defining an asset management approach. The report then develops an architecture for a signal system asset management system, and presents an analysis illustrating how such a system could be used to evaluate tradeoffs across different options for addressing signal system deficiencies. (Federal Highways Administration Report FHWA-HOP-05-006, December 2004, 62 p.)

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