Transportation Intelligence

Volume 8 Number 1

February 2010

Pavements

Administration

Traffic Control

Safety

Feedback

Safety
A Primer on Safety Performance Measures for the Transportation Planning Process
This Primer is a tool to help State and local practitioners, transportation planners, and decision-makers identify, select, and use safety performance measures as a part of the transportation planning process. The Primer draws from current literature, professional experience, and State DOT and MPO practice. Key elements of the Primer include: a definition of performance measures; a step-by-step description and flowchart showing how safety performance measures can be identified and integrated into the transportation planning process; characteristics of effective performance measures; a checklist to assess an organization’s current status with respect to the use of safety performance measures in the transportation planning and decision-making process; a list of references; and case studies of noteworthy practice. (US Federal Highway Administration Report FHWA-HEP-09-043, September 2009, 32p.)

Pavements
Centerline (Longitudinal) Joint Adhesive Performance: Two to Three-Year Review
This report discusses preliminary evaluations of adhesive use along longitudinal paving joints on hot mix asphalt pavements to help prevent longitudinal cracking. Seven pavements where adhesive was applied to the vertical or sloped face of the first lane paved prior to overlaying the second lane are being evaluated for development of centerline cracking and ravelling. This report only evaluated the use of longitudinal joint adhesives on overlays, although the adhesive could be used on the top layer of newly reconstructed pavements. This is a review of the distress found after at least one followup visit to all sites. A summary of the literature search is also presented. (New York Department of Transportation Special Report 149, November 2009, 41p.)

Pavements

Synthesis of Warm Mix Asphalt Paving Strategies for Use in Montana Highway Construction
Warm Mix Asphalt (WMA) used as an alternative to conventional Hot Mix Asphalt (HMA) has gained national prominence. WMA uses technological advances that reduce the temperature needed to produce and compact asphalt for the construction of pavements, which results in lower costs, improved worker health, increased safety and reduced environmental impacts. Twelve WMA technologies are currently identified. Significant work has been conducted to demonstrate construction practices and to develop mixture design procedures. Twelve states currently have specifications for WMA. This report summarizes work performed to date that is pertinent to Montana DOT's desire to move forward with implementation of WMA. Recommendations are given for research and implementation activities that should be followed to more broadly employ WMA technologies as a standard paving practice in Montana.(Montana Department of Transportation Report FHWA/MT-09-009/8117-38, November 2009, 212p.)

Quality Management of Pavement Condition Data Collection
Transportation agencies are developing procedures and guidelines for managing the quality of pavement data collected to ensure the data meet the needs of the pavement management process. This study reviews the quality management practices being employed by public highway agencies for automated, semi-automated, and manual pavement data collection and delivery. Information was gathered through literature review, surveys of U.S. state and Canadian provincial public agencies and private contractors, and selected interviews. (TRB National Cooperative Highway Research Program Synthesis of Highway Practice 401, 2009, 152p.)

Quantify the Energy and Environmental Effects of Using Recycled Asphalt and Recycled Concrete for Pavement Construction - Phase 1 Final Report
The objective of this study is to quantify the energy and environment impacts from using recycled materials for highway construction. Specifically, when recycled asphalt pavement is re-used for producing hot mix asphalt or when recycled concrete aggregate is used in concrete, how much energy will be utilized and how much are the greenhouse emissions. This study quantified the impact of using recycled asphalt pavement (RAP) in hot mix asphalt and recycled concrete aggregate in concrete on energy consumption and greenhouse gas emission. For RAP, the impact on energy consumption and greenhouse gas emission is affected by a few factors, such as moisture content in RAP, hot mix asphalt discharge temperature and RAP content. A mathematical model was developed to determine the impact. For recycled concrete aggregate for concrete production, impact on energy consumption and greenhouse gas emission is largely affected by transporting distances. A simple model was also developed for recycled concrete aggregate. (New York State Department of Transportation report, August 2009, 49p.)

Back to Top

Structures

Bridge Scour and Stream Instability Countermeasures; Experience, Selection, and Design Guidance - Third Edition; volume 1
This manual is presented in two volumes. Volume 1 is organized to:
-Provide strategies and general guidance for developing a Plan of Action for a scour critical bridge (Chapter 2)
-Highlight the various groups of countermeasures and identify their individual characteristics (Chapter 2)
-For a wide-range of countermeasures, list information on their functional applicability to a particular problem, their suitability to specific river environments, the general level of maintenance resources required, and which DOTs have experience with specific countermeasures (Chapter 2 and the Countermeasures Matrix).
-Provide general criteria for selection of countermeasures for bridge scour and stream instability problems (Chapter 3)
-Discuss countermeasure design concepts including design approach, hydraulic analysis, and environmental permitting (Chapter 4).
-Provide an overview of design considerations related to riprap: including filters; riprap specifications, testing and quality control; riprap failure modes, and inspection guidance (Chapter 5).
-Discuss biotechnical engineering approaches and provide conceptual guidelines (Chapter 6).
-Provide detailed design guidelines for specific bridge scour and stream instability countermeasures (Chapter 7 and Volume 2, Design Guidelines 1 through 19).
-Summarize general guidance for other countermeasures and case histories of countermeasure performance (Chapter 8).
-Provide criteria for selecting portable and fixed instrumentation for monitoring scour at bridges (Chapter 9).
US Federal Highway Administration Report FHWA-NHI-09-111, September 2009, 256p.)

Bridge Scour and Stream Instability Countermeasures; Experience, Selection, and Design Guidance - Third Edition; volume 2
Volume 2 presents detailed Design Guidelines for 16 stream instability and bridge scour countermeasures. Design Guidelines are presented for the following functional applications:
-Countermeasures for stream instability
-Countermeasures for streambank and roadway embankment protection
-Countermeasures for bridge pier protection
-Countermeasures for abutment protection
-Granular and geotextile filter requirements
-Special Applications
(US Federal Highway Administration Report FHWA-NHI-09-112, September 2009, 376p.)

Shear Repair Methods for Conventionally Reinforced Concrete Girders and Bent Caps
Thirteen large-scale girders and two bent caps that replicated as close as possible bridge components from the 1950s were cast and loaded to cause initial cracking similar to that observed in the field. The girders were repaired with epoxy crack injection, internal steel bars, external steel bars, surface bonded CFRP, and near-surface mount CFRP. The bent caps were repaired with surface-bonded CFRP and post-tensioning. The beams were loaded to failure while sensors recorded how the beams deformed. In addition, two bridges, one with surface-bonded CFRP strengthening and one with internal steel strengthening, were instrumented before and after strengthening to assess changes in behavior. The test results were used in conjunction with previous research to compare the repair methods based on ten attributes such as shear capacity improvement, aesthetics, durability, and installation requirements. (Oregon Department of Transportation report FHWA OR-RD-10-09, December 2009, 260p.)

Back to Top

Environment

New Approaches to Ecological Surveys
The objectives of this synthesis were to survey transportation and natural resource professionals familiar with transportation systems to identify ecological survey needs related to transportation activities and to identify technologies, techniques, and innovative methods to fulfill those needs. These technologies, techniques, and methods, collectively called new approaches, include data collection, its analysis and delivery, how it can be used in planning and operations, and cooperative working relations. The audience for this synthesis includes transportation professionals responsible for planning, designing, constructing, operating, and maintaining transportation projects and the road corridor in an environmentally and fiscally responsible manner, as well as professionals in natural resource agencies and other organizations who work with departments of transportation (DOTs) on these issues. (TRB National Cooperative Highway Research Program Synthesis Report 400, 2010, 84p.)

Relationships Between Lighting and Animal-Vehicle Collisions
In 1990, there were 106 traffic fatalities in the United States in crashes for which a collision with an animal was the first harmful event; by 2007 this level had risen to 223—a 110% increase. Analyses of annual trends suggest that this increase cannot be fully explained by increases in vehicle miles travelled, nor by changes in the general fatal and nonfatal crash rates. Animal-vehicle collisions (AVCs) represent a small but increasing share of the overall crash picture. Daily and seasonal AVC crash trends were examined and appear to follow the activity patterns of the U.S. deer population. This involves peaks in the hourly crash levels around dawn and dusk, and a seasonal peak during October and November. AVC crash distributions are presented by state. The odds of an AVC in darkness were modeled as a function of posted speed limit in a series of logistic regressions. Higher posted speeds were associated with proportionally greater crash risk in darkness. The effect is observed for fatal collisions compiled from the Fatality Analysis Reporting System (FARS), and for injury and property-damage-only (PDO) crashes compiled from Michigan crash datasets. One implication of the effect is that countermeasures designed to extend a driver’s preview time for animals, such as headlighting and night-vision systems may help reduce the risk of AVCs. (University of Michigan Transportation Research Institute Report UMTRI-2009-35, October 2009, 26p.)

Back to Top

Administration

Guidebook for Rural Demand-Response Transportation: Measuring, Assessing, and Improving Performance
This guidebook will be of interest to rural public transportation systems that provide demand-response transit (DRT) services and to the communities they serve. The guidebook is a resource to assist DRT systems to measure, assess, and improve their performance, focusing on DRT systems in rural areas. A companion report was prepared in 2008 (TCRP Report 124) which focused on DRT systems in urban areas. (TRB Transit Cooperative Research Program Report 136, 2009, 98p.)

Exposure Modelling of Productivity-Permitted General Freight Trucking on Uncongested Highways
The research designs, develops, validates, and applies an exposure model of productivity-permitted general freight trucking on uncongested highways. Productivity-permitted general freight trucks (long trucks) are multiple trailer configurations, consisting of van trailers, which exceed basic vehicle length limits but operate within basic weight restrictions. The three predominant long trucks in North America are Rocky Mountain doubles (Rockies), Turnpike doubles (Turnpikes), and triple trailer combinations (triples). Despite widespread use of long trucks for many years and recent infrastructure investments, there is a knowledge deficiency about long truck exposure. The research uses the transportation systems analysis approach to design, develop, and validate the long truck exposure model. Exposure is expressed as an explanatory variable in three principal dimensions (volume, weight, and cube), which is needed for predicting transportation system impacts of long truck operations. The research applies the model to clarify issues that should be considered in establishing charges for long truck permits, determining long truck safety performance, and developing load spectra for long trucks. (University of Manitoba Department of Civil Engineering PhD thesis, 2009, 202p.)(To borrow this book please contact the TIS.)

Back to Top

Traffic Control

Incorporating Weather Impacts in Traffic Estimation and Prediction Systems
Dynamic Traffic Simulation-Assignment models are gaining wider acceptance and use to support transportation network planning and traffic operations decision-making. Significant improvements in traffic estimation capabilities and overall utilities of these systems for traffic management can be achieved by upgrading or adjusting them to account for the impacts of weather. This report presents the results of a study to develop weather-sensitive dynamic traffic assignment (DTA) models for Traffic Estimation and Prediction (TrEPS) application, which addresses both supply and demand aspects of the response to adverse weather, including user responses to various weather-specific interventions such as advisory information and control actions. (US Federal Highway Administration Report FHWA-JPO-09-065, September 2009, 110p.)

Regional Traffic Signal Operations Programs: An Overview
This report provides an overview of practices related to developing and sustaining a Regional Traffic Signal Operations Program. The purpose for a Regional Traffic Signal Operations Program is to provide regional partners a formal framework to collectively manage the signal system performance for efficiency and consistency. A key benefit of a regional program is the development of projects that are of a magnitude that they can be included in a regional or state transportation improvement program (TIP). There are many benefits to the development of a regional traffic signal management and operations program. Agencies and users benefit from regional traffic signal operations programs as planners, engineers, and operators can provide an effective and efficient traffic signal system to the public and also provide higher levels of customer service without increasing costs. Additionally, by sustaining collaboration, regional operators can demonstrate to the public and elected officials that progress is being made on community goals, which then can be leveraged for future funding. Agencies and jurisdictions within a region that use a common framework for developing and establishing expectations, managing resources, and building relationships will result in more successful systems both individually and region-wide. (US Federal Highway Administration Report FHWA-HOP-09-007, October 2009, 76p.)

New Traffic Calming Device of Choice
Speed lumps consist of two or more raised and rounded areas placed laterally across a roadway with precisely spaced gaps allowing the wheel tracks of fire-rescue vehicles to pass between the lumps. Speed reduction and costs are similar to speed humps; however, speed lumps do not significantly slow fire-rescue vehicles. (ITE Journal, December 2009, pp. 26-31.) (To obtain this article, please contact the TIS.)

Back to Top

Safety

Improving Pedestrian and Motorist Safety Along Light Rail Alignments
This report addresses pedestrian and motorist behaviors contributing to light rail transit (LRT) safety and describes mitigating measures available to improve safety along LRT alignments. The report also includes recommendations to facilitate the compilation of accident data in a coordinated and homogeneous manner across LRT systems. Finally, the report provides a catalog of existing and innovative safety devices, safety treatments, and practices to use along LRT alignments. The results of this research may be useful to transit operators, consultants, and state safety oversight agencies. (TRB Transit Cooperative Research Program Report 137, 2009, 115p.)

Guidance for the Design and Application of Shoulder and Centerline Rumble Strips
This report provides guidance for the design and application of shoulder and centerline rumble strips as an effective crash reduction measure, while minimizing adverse effects for motorcyclists, bicyclists, and nearby residents. Using the results of previous studies and the research conducted under this project, safety effectiveness estimates were developed for shoulder rumble strips on rural freeways and rural two-lane roads and for centerline rumble strips on rural and urban two-lane roads. The report will be of particular interest to safety practitioners with responsibility for roadway design. (TRB National Cooperative Highway Research Program Report 641, 2009, 181p.)

Crash Modification Factors Clearinghouse
A crash modification factor (CMF) is a multiplicative factor used to compute the expected number of crashes after implementing a given countermeasure at a specific site. The Crash Modification Factors Clearinghouse houses a Web-based database of CMFs along with supporting documentation to help transportation engineers identify the most appropriate countermeasure for their safety needs. (US Federal Highway Administration web site)

Identifying Intersection-Related Traffic Crashes for Accurate Safety Representation
This paper investigates the intersection safety influence area to achieve a more reliable way of identifying intersection-related crashes and hence accurately estimating an intersection’s safety. (ITE Journal, December 2009, pp. 38-44.) (To obtain this article, please contact the TIS.)

Back to Top