Transportation Intelligence

Volume 8 Number 2

April 2010

Pavements
Administration
Traffic Theory
Safety
Feedback

Winter Maintenance
Development of an Improved Agricultural-Based Deicing Product
Snow and ice removal on public streets is a critical part of the work of departments of transportation in northern U.S. states, including Iowa. Iowa is also a state rich in agricultural resources, some of which undergo industrial processes that generate a number of byproducts, e.g., in converting corn to ethanol or soy to biodiesel. The focus of this work is therefore to investigate by-products from agricultural processes that may be suitable for use as deicing applications. This topic has been investigated in the past by others, with many patented products described in the literature. An initial screening was carried out to assess the potential acceptability of selected commercial products, as well as a glycerol developed for this project. (Iowa Highway Research Board Project Report TR-581, January 2010, 108p.)

Construction
Work Zone Mobility and Safety Self-Assessment 2009 National Report
To help States evaluate their work zone practices, and to help assess work zone practices nationally, the Federal Highway Administration (FHWA) developed the Work Zone Mobility and Safety Self Assessment (WZ SA) tool. The WZ SA tool consists of a set of 46 questions designed to assist those with work zone management responsibilities in assessing their programs, policies, and procedures against many of the good work zone practices in use today. The policies, strategies, processes, and tools identified in the WZ SA were gathered from the best practices currently in place in State departments of transportation (DOTs), metropolitan planning organizations, and local municipalities. Many of the items can be found in the Work Zone Best Practices Guidebook (available at http://www.fhwa.dot.gov/workzones). (US Federal Highway Administration report, October 2009, 41p.)

Environment
Update for Wildlife-Vehicle Collision and Crossing Mitigation Plan for Hwy 93S in Kootenay and Banff National Park
In 2008 a study was conducted to identify mitigation measures aimed at reducing wildlife-vehicle collisions and providing safe crossing opportunities for wildlife along Hwy 93S through Kootenay and Banff National Park (Huijser & Paul, 2008; Huijser et al., 2008a). The current manuscript provides an update to these reports. (Montana State University Western Transportation Institute Report 433308, February 2010, 45p.)

Pavements

Interfacial Fracture Energy: An Indicator of Bituminous Material Adhesion
This paper demonstrates that the pressurized blister test can be an effective method to predict binder-aggregate bonding. Recently, the blister test has been introduced as a reliable approach to predict the bonding between bituminous sealant and aggregate. Since this test measures a geometry-independent parameter that is an inherent property of the interface, the test can be applied to any bituminous material, from the softest bituminous crack sealant to the most brittle binder. With very brittle material, cohesive failure becomes a concern. Such a failure can be easily prevented by an increase in the thickness of the adhesive specimen. However, an increase in specimen thickness also gives rise to shear forces that cannot be neglected in the analysis. Utilizing theoretical and experimental analyses, this paper presents the effect of shear forces on the interfacial fracture energy (IFE) of adhesive bituminous materials. The effect of shear forces on blister deflection is shown as a function of material thickness. In addition, the dependence of IFE of bituminous materials on temperature and rate of loading was investigated through laboratory testing. An optimum temperature and loading rate can be identified for each material where IFE is optimized. This may help select appropriate binder/sealant - aggregate pairs for improved performance under defined environmental conditions. A version of this document is published in: Journal of the Association of Asphalt Paving Technologists, 77, pp. 827-850, March 01, 2010. (National Research Council of Canada report NRCC-50085, March 2010, 25p.)

FWD Calibration Center and Operational Improvements: Redevelopment of the Calibration Protocol and Equipment
The objective of this study is to upgrade the existing FWD calibration system to make calibration sustainable for the next decade without a loss of quality while ensuring any new procedures are compatible with all brands of FWDs sold in the United States. This involves upgrading the hardware and software used in calibration to take advantages of improvements in technology. The primary result of the FWD calibration procedure is to obtain “gain factors” used to correct FWD load cell and deflection sensor data to agree with the calibration instrumentation. (US Federal Highway Administration report FHWA-HRT-07-040, February 2009, 261p.)

Ground Penetrating Radar (GPR) Analysis
The objective of this work is to evaluate the feasibility of expanding the MDT's Ground Penetrating Radar (GPR) program to a broader range of pavement evaluation activities. Currently, MDT uses GPR in conjunction with its Falling Weight Deflectometer (FWD) data collection program to provide layer thickness data for backcalculation. This program has included a review of literature and software dealing with pavement applications of GPR, a survey of state highway agency (SHA) use of GPR for pavement applications, a review of MDT's GPR program, and a review of MDT's pavement structures, environment, and pavement management, and rehabilitation practices. Based on an evaluation of MDT's rehabilitation and reconstruction practices, it appears that the GPR program can be expanded to provide useful information for the following applications: (a) calculation of structural number for pavement reconstruction and rehabilitation design; (b) insuring proper depth control for mill and fill rehabilitation, and cold in-place recycling; (c) improved structural capacity calculation for network level evaluation; and (d) quality assurance of new pavement thickness and density. (Montana Department of Transportation Report FHWA/MT-09-005/8201, November 2009, 105p.)

Investigation of the Rolling Wheel Deflectometer as a Network-Level Pavement Structural Evaluation Tool
A growing area of interest in pavements research is developing new and faster technologies that are well suited for nondestructively assessing the pavement structure without causing delays to the traveling public. One recently developed system, the rolling wheel deflectometer (RWD), measures the response from one-half of an 18-kip single-axle load traveling at normal highway speeds. This technology can measure deflections for approximately 200 to 300 lane-miles per day, which is approximately 10 times the production of traditionally used FWD testing. The primary advantages of using RWD are twofold: the testing can be conducted at highway speeds for increased safety, and the loading by the RWD is thought to replicate better the actual dynamic effects on pavements caused by heavy vehicle loading. This report provides the results of RWD testing on three Virginia routes and a comparison of the deflection results obtained with RWD and FWD testing on sections of I-64 and I-81. (Virginia Transportation Research Council report VTRC 10-R5, January 2010, 33p.)

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Structures

Monitoring for durability and structural behaviour of medium and long span concrete bridges
The ageing and deterioration of highway bridges can have very serious consequences in terms of reduced safety, serviceability and functionality. Many bridges built in the 1960’s and 1970’s are considered deficient by today’s standards. The widespread deterioration and some recent failures have highlighted the importance of developing and implementing effective inspection strategies, including structural health monitoring systems, which can identify structural problems before they become critical and endanger public safety. Continuous monitoring is becoming necessary due to ageing of bridges, increased traffic loads, changing environmental conditions, and reduced capacities, especially for medium and long-span bridges given the severe consequences of failure. The implementation of monitoring programs can assist in optimizing the in-depth inspection, maintenance, rehabilitation, and replacement of bridge structures. The continuous and simultaneous measurements at critical discrete points of a bridge system will allow the assessment of its performance with respect to different limit states, including safety and serviceability. Prediction models, updated from such monitoring data, can optimize intervention strategies as to how and when to repair or rehabilitate thus extending service life and reducing life-cycle costs. The objectives of this paper are: (i) to present an approach for the efficient use of structural health monitoring into the durability and structural reliability assessment process; (ii) to highlight the applicability of the approach to short, medium and long-span bridges; and (iii) to demonstrate the effective use of field monitoring data for the calibration and updating of service life prediction models. A case study on a medium-span concrete highway bridge is also presented and used to illustrate the approach. (National Research Council of Canada paper NRCC-51153, February 2010, 10p.)

The Influence of Galvanic Coupling on Corrosion of Carbon Steel Coupled with Stainless Steels for Use in Concrete Structures
The judicious use of stainless steel and carbon steel in concrete structures—using stainless steel only in areas with a high risk of corrosion and carbon steel in low-risk areas—could be a viable option for reducing lifetime cost, and extending service life. However, the concern about the risk of galvanic corrosion between the two different steels has prevented this application in the field. This paper investigates the galvanic coupling behaviours of carbon steel and three different stainless steels (304LN, 316LN and 2205). The results indicate that the oxygen reduction reaction is a rate-determining step and is much lower on stainless steel than on passive carbon steel. Therefore, the galvanic coupling current between stainless steel and corroding carbon steel is lower than the coupling current between passive and corroding carbon steels. Consequently, the combination of stainless steel with carbon steel will not increase the risk of corrosion of carbon steel. (National Research Council of Canada paper NRCC-52711, January 2010, 15p.)

French Study Tour to the United States of America on Bridge Management and Maintenance
This report was jointly written by all nine members of the French delegation that traveled to the United States during the week of November 8-15, 2008. This delegation, which featured representatives from LCPC, SETRA and ADSTD, vistited the following institutions: the Federal Highway Administration (FHWA) and its laboratory (Turner-Fairbank Highway Research Center), the State Departments of Transportation (DOT) of New York and California, the Bureau of Bridges of the City of New York, and Columbia University in New York City (see Appendix 15 for the meanings of the various acronyms used in this report). (rapport du Laboratoire Central des Ponts et Chaussées, Mai 2009, 152p.)

Determining Localized Anode Condition to Maintain Effective Corrosion Protection
Thermal sprayed zinc anodes used for impressed current cathodic protection of reinforced concrete deteriorate over time. Two different technologies, ultrasound and electrical circuit resistance combined with water permeability, were investigated in the laboratory to determine whether they were feasible methods for estimating anode condition. (Oregon Department of Transportation Report FHWA-OR-RD-10-11, January 2010, 134p.)

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Administration

Value Capture for Transportation Finance: Technical Research Report
As vehicles become more fuel-efficient and overall levels of travel stagnate in response to increases in fuel prices, conventional sources of revenue for transportation finance such as taxes on motor fuels have been put under increasing pressure. One potential alternative as a source of revenue is a set of policies collectively referred to as value capture policies. Value capture policies seek to generate revenue by extracting a portion of the gains in the value of land that result from improvements to transportation networks. In this report we identify a set of eight policies that contain elements of the value capture approach. These policies include land value taxes, tax increment financing, special assessments, transportation utility fees, development impact fees, negotiated exactions, joint development, and air rights. (University of Minnesote Center for Transportation Studies report CTS 09-18, June 2009, 373p.)

Overlooked Density: Re-Thinking Transportation Options in Suburbia
Suburban multifamily housing is ubiquitous throughout this country and currently comprises nearly one in four units of suburban housing. Although typically located near commercial development, it is often developed without connections to its surrounding and hence fails to reach its potential for promoting active travel and supporting smart growth goals. Through interviews with architects, planners, developers, and property managers of case study multifamily developments from Oregon, Arizona, Florida, and Massachusetts, this report focuses on the ways regulation, typical development practice, and design culture have propagated the typical disconnected and enclaved forms of suburban multifamily development. The report then proposes ways in which current planning, development, and design practices might shift in order to take advantage of this growing housing trend and create more livable, less congested, and multi-modal suburban communities. (Oregon Transportation Research and Education Consortium report OTREC-RR-10-03, February 2010, 36p.)

A Domestic Scan of Congestion Pricing and Managed Lanes
Congestion pricing and managed lanes have been receiving increasing attention in the U.S. as viable congestion management strategies and as ways to generate additional revenue. The purpose of this project was to conduct a scan of selected Metropolitan Planning Organizations (MPOs) and State Departments of Transportation (State DOTs) to determine how they are planning for congestion pricing and managed lanes. The scan was designed to identify current practices for regional consideration of congestion pricing and managed lanes as strategies for managing congestion as part of the broader transportation planning process. (US Federal Highway Administration Report, April 2009, 59p.)

Handbook of Emergency Management for State-Level Transportation Agencies
This research project was intended to lay the groundwork for establishing priorities that would lead to a mature management capability for emergencies, disasters and catastrophes. Because transportation agencies typically have significant experience with “normal emergencies” on the roadways, and routinely work with state police and state fire agencies in disaster situations, some elements of a mature emergency management capability have not been emphasized. The following activities should be completed by a state level transportation agency to ensure a robust response and recovery capability. An Emergency Operation Center (EOC) should be created, and reasonable alternative EOC sites selected and developed. The Emergency Operations Plan (EOP) and Continuity of Operations Plan (COOP) should be developed, staff should be trained on the plans, and regular exercises should be held. Guidance on these steps is included, as well as detailed examples of some COOP materials. A complete set of EOC model checklists is available in another MTI publication, The Role of Transportation in Campus Emergency Planning, which is available as a free download at http://www.transweb.sjsu.edu/MTIportal/research/publications/documents/Role%20of%20Transportation%20(Complete%20with%20Cover).pdf. (San José State College Mineta Transportation Institute report 09-10, February 2010, 124p.)

A Case Study of Enterprise Historic Resources Information Management In Large Transportation Agencies
Historic resources are in some way managed by every transportation agency in the nation. Transportation agencies manage historic and prehistoric archaeological sites, buildings, structures, objects, routes, landscapes, and districts to prevent damage to such resources and to mitigate damage when it is unavoidable. In order to track known resources, transportation agencies often keep local files in a variety of forms, rely upon external sources of information (e.g., historic preservation agencies at the state level), and depend upon staff expertise gained by years of local work. The present study focuses on defining how the district office information systems for historic resources can (and cannot) be used to create an enterprise information management model specific to historic resources within Caltrans. Results of this study range from findings specific to Caltrans and its district offices to general findings that should apply to any transportation agency contemplating an enterprise-wide system for managing cultural resources. (San José State College Mineta Transportation Institute report CA-MTI-09-2502, January 2010, 66p.)

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Traffic Theory

Trip Generation Characteristics of Special Generators
Special generators are introduced in the sequential four-step modeling procedure to represent certain types of facilities whose trip generation characteristics are not fully captured by the standard trip generation module. They are also used in the traffic impact analysis to represent new developments. The objectives of this research project are twofold: 1) to analyze qualitatively trip generation characteristics of special generators and provide recommendations on how to improve the modeling of special generators in the Florida Standard Urban Transportation Model Structure (FSUTMS); 2) to examine the advantages and disadvantages of two modeling approaches, i.e., the link distribution percentage method and the special generator method, for performing traffic impact analyses for proposed developments. (Florida Department of Transportation Report TRC-FDOT-76173-2009, March 1, 2010, 85p.)

Developing a Technique that Predicts the Impacts of Transportation Demand Management (TDM) on a Transportation System
This study researched ways to incorporate transportation demand management (TDM) strategies in software such as ITS Deployment Analysis System (IDAS) that would allow state, regional, and local transportation planners and decision-makers to actively consider TDM strategies as a congestion mitigation tool, just as practiced with ITS deployments that are designed to increase the efficiency of managing traffic capacity. The expectation was that this National Center for Transit Research (NCTR)/FDOT project would help analysts identify and choose the most cost-effective mix of program elements for improving traffic and air quality conditions in a corridor and see how the cost and mix varies with the desired level of change. (Florida Department of Transportation report BDK85 WO 977-06, February 2010, 50p.)

Investigation of Freeway capacity: a) Effect of Auxiliary Lanes on Freeway Segment Volume Throughput and b) Freeway Segment Capacity Estimation for Florida Freeways
Auxiliary lanes are generally used to reduce the traffic turbulence created by merging and diverging movements and are primarily used by vehicles either entering ot exiting the freeway. The Highway Capacity Manual (HCM) does not offer explicit guidance on the benefit of adding an auxiliary lane between an on- and off-ramp. The objective of this part of the project was to quantify the additional traffic volume that can be accommodated on a freeway segment by connecting an on-rampto an off-ramp with an auxiliary lane. The approach used was to identify the traffic volume level at which each level of service density threshold was met for the conditions of with and without an auxiliary lane. The CORSIM simulation program was used to generate the data upon which to establish the quantitative effect of an auxiliary lane. (Florida Department of Transportation Report TRC-FDOT-73157-2010, March 2010, 162p.)

Improving Capacity Planning for Demand-Responsive Paratransit Services
This report proposes and evaluates two ideas for improving efficiency and service quality of paratransit operations. For carrying out this analysis, the authors use data from Metro Mobility, the agency responsible for providing ADA-mandated transportation services in the Twin Cities. The first idea is to re-optimize routes developed by Metro Mobility’s route-building software (a commercial product named Trapeze) at the end of each day of booking operations to reduce the total time it takes to serve booked trips. The second idea evaluates the selective use of non-dedicated vehicles and service providers (e.g. taxi services) for lowering operational costs. Mathematical models and computer algorithms are developed for each of these approaches. These are then tested on actual operational data obtained from Metro Mobility. (Minnesota Department of Transportation Research Report 2008-09, April 2008, 78p.)

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Safety

Safety Performance Functions for Intersections
Road safety management activities include screening the network for sites with a potential for safety improvement (Network Screening), diagnosing safety problems at specific sites, and evaluating the safety effectiveness of implemented countermeasures. The state-of-the-art methodologies for conducting these activities make use of statistical models to predict expected accident frequencies using traffic volumes and other site characteristics as the input to the models (known as Safety Performance Functions or SPFs). Colorado Department of Transportation (CDOT) has previously developed SPFs to identify freeway and rural roadway segments that have the potential for accident reduction. This report documents the data collection, modeling efforts, and findings of a research project to develop SPFs for ten categories of intersections. (Colorado Department of Transportation report CDOT-2009-10, December 2009, 63p.)

Through, Over, or Under Guardrail Penetration by Guardrail Height
This report evaluates whether a clear correlation between guardrail height and penetration of the guardrail exists in the collision and roadside features inventory datasets available for Washington State. In particular, do guardrail heights of 27 inches or lower experience more through, over, or under penetrations (TOU) than 28 inch or greater guardrail installations (Washington State Department of Transportation Report Wa-RD 742.1, December 2009, 15p.)

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