Transportation Intelligence

Volume 2 Number 1

February 2004

Urban

Maintenance

Management

Pavements

Safety

Research

Structures

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Pavements
Performance of stone matrix asphalt pavements in Maryland
Maryland State Highway Administration began to specify SMA on major high traffic, high speed arterial roads in 1992. Initial Maryland efforts attempted to duplicate as nearly as possible the European technology for design, production and placement of SMA. These procedures evolved as MSHA acquired local experience with this new material. Maryland views SMA as a premium paving material that is best suited for demanding applications. (Asphalt Review, December 2003, pp. 17, 20-21.)

Maintenance
Extent of Top-Down Cracking in Colorado
The object of this study was to determine the extent of "top-down cracking" in Colorado, what causes it, how can it be prevented, if it occurs how is the distress treated, and how quickly does the distress need to be treated. Twenty-five sites were cored to determine the type of distress in terms of topdown versus reflective cracking. The longitudinal crack in 72% (18 of 25) of the sites that were cored was top-down related cracking. Of these 18 sites 67% had visual evidence of segregation. (Colorado Department of Transportation Report CDOT-DTD-R-2003-7, July 2003, 53 p.)

Safety
Gloucester Safer City - Final Report
'Gloucester Safer City' is the title given to a major road safety initiative started in 1996 by the UK Department for Transport (DfT). The purpose was to demonstrate to highway authorities that road accidents and casualties in urban areas can be substantially reduced if significant funds are made available and towns are treated using safety engineering in a strategic manner, but also with safety integrated into other town policies and activities. (TRL Report TRL589)

Urban

Designing Horizontal Curves for Low-Speed Environments
This project was a pilot study to explore alternative criteria for the geometric design of low-speed urban horizontal curves. Low-speed was defined as 70 kilometers per hour (km/h), or 45 miles per hour (mph), or less. The researchers collected data and then developed alternative low-speed urban horizontal curve design paradigms. The results were compared with the practices in the current American Association of State Highway and Transportation Officials A Policy on Geometric Design of Highways and Streets (Green Book). The data indicated that a driver's speed in advance of a curve can influence speed within the curve, and that a portion of drivers exceed the low-speed urban side friction factors in the 2001 Green Book. (Mack-Blackwell Rural Transportation Center Report MBTC 2019, February 2003)

Second-best pricing for imperfect substitutes in urban networks
This paper considers second-best pricing as it arises through incomplete coverage of full networks. The main principles are first reviewed by considering the classic two-route problem and some extensions that have been studied more recently. In most of these studies the competing routes are assumed to be perfect substitutes, which is probably not the case for most parallel roads in reality, and even less likely for the case where competing connections represent different transport modes. In this paper a modelling framework in which the alternatives are imperfect substitutes is developed and numerical results for two roads and two modes are presented. (Tinbergen Institute Discussion Paper TI 2003-085/3, 2003, 49 p.)

Ecrans anti-bruit, performances et esthétique progressant (Anti-noise Screens, Performance and Esthetics Progress)
Traffic noise, which is the most commonly expressed annoyance in France, is a topical concern. The government has revealed an action plan to combat noise at more than 3000 "noise black points" (building locations) along roads and railways. (Route Actualité/Road News, Décembre 2003, p. 30-35) (Request this item from TIS)

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Maintenance

Rut Mitigation Techniques at Intersections
This document outlines the best practice for the cost-effective, technically sound mitigation of intersection asphalt pavement rutting, and provides a municipal intersection pavement rut mitigation action plan to ensure good structural and functional performance of existing and new asphalt pavements. It is based on practical Canadian experience supplemented by a questionnaire and technical information scan. (National Guide to Sustainable Municipal Infrastructure, September 2003, 49 p.)

Standardising Rut Depth Measurements
The project Harmonising Automated Rut Depth Measurements sought to establish whether outputs from the different systems were compatible with each other and could be referenced back to a single standard value. The aim was to develop a standard methodology and transfer functions for rut depths, thereby enabling the harmonisation of measurements from different systems. (Transearch New Zealand, December 2003, p. 3-4)

Principles of Pavement Preservation
Pavement preservation involves a variety of timely treatments and repairs- tailored to each highway agency's system needs-to extend the life of the asset at a relatively low cost.. (TR News, September-October 2003, p. 4-9)

Effectiveness of Highway Pavement Seal Coating Treatment
Past research on seal coating effectiveness has generally indicated that both short- and medium-term benefits are associated with this treatment. Regarding the relationship between short-term effectiveness and initial pavement condition, results of past studies have been equivocal: some studies found that lower levels of initial pavement condition are associated with lower effectiveness after seal coating treatment, while results of other studies were to the contrary. This paper, in developing seal coating effectiveness models, explains the findings of both schools of thought. (Journal of Transportation Engineering, January/February 2004, p. 14-23) (Request this item from TIS)

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Management

Coordinating Infrastructure Works
This document outlines best practices for the coordination of infrastructure works, to minimize disruption and maximize value. All public works managers have had public complaints about the lack of effective coordination among the various infrastructure components. How well this issue gets handled, significantly affects the overall effectiveness of infrastructure providers and, therefore it is important for the various infrastructure renewal programs to be coordinated to the maximum extent possible. (National Guide to Sustainable Municipal Infrastructure, July 2003)

Auctioning Concessions for Private Roads
Private toll roads are now seriously considered as an alternative to public (free access) road infrastructure. Nevertheless, complete private provision without governmental control is only rarely considered. A main consideration against private roads would be that operators would be primarily interested in maximizing profits, which - given the market power they will have - will typically not lead to welfare-maximizing tolls and capacities. An important question is whether these discrepancies can be mitigated by a proper design of auctions for concessions of private roads. This paper therefore analyses capacity choice and toll setting by private investors in a competitive bidding framework organized by the government. (Tinbergen Institute Discussion Paper TI 2004-008/3, 2004, 27p.)

Improving the Condition of Bridge Networks: Michigan Crafts a Preservation Program
Michigan's strategic investment plan for its network of trunkline bridges includes an important role for preventive maintenance. (TR News, September/October 2003, p. 26-30) (Request this item from TIS)

Framework for a Regional Transit Asset Management System
Emerging system concepts and frameworks that incorporate enabling technologies have made asset management systems more powerful. This article shows how an initiative launched by the Chicago, Illinois Regional Transportation Authority to design a transit asset management system is an important first step in implementing 21st-century transit asset management. (ITE Journal, September 2003, p. 42-47.) (Request this item from TIS)

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Pavements

Road Quality Thresholds from the Motorists' Perspective
The primary research objective of the project was to determine the International Roughness Index (IRI) thresholds that provide motorists with satisfactory ride quality and the IRI thresholds that represent fair, good, and excellent ride quality. A secondary objective was to establish motorist satisfaction thresholds, when possible, for additional highway features - such as lane width, shoulder width, ridge width, pavement condition, and overall roadway condition. The report focuses on the subjective ratings of ride quality and its relationship to IRI. (Pennsylvania DoT.)

Development of performance-based specifications for unbound granular materials: Issues and recommendations
This paper provides a review of current Austroads Member Authorities pavement material specifications, their origins, strengths and weaknesses. In addition, it examines the issues in the development of performance-based specifications for unbound granular materials as well as the benefits to be gained from the implementation of 'performance-based' material specifications. Areas in the performance-based specifications that require refinement and verification are identified and further research in these areas is recommended. (Road and Transport Research, December 2003, p. 13-25)(Request this item from TIS)

Permanent Deformation in Flexible Pavements
This paper presents a mechanistic-empirical framework for evaluating permanent deformation in flexible pavements. The procedure uses rational material properties and can be used as an analysis tool, as a companion to the design method. It is a compromise between simple and advanced approaches, between linear elasticity and nonlinear incremental finite element approaches. (Journal of Transportation Engineering, January/February 2004, p. 6-13.)(Request this item from TIS)

Comportement de la moquette en béton à hautes performances sous sollicitations thermiques et trafic accéléré (Behavior of High-Performance Concrete Covering Submitted to Thermal Loads and Accelerated Traffic Conditions)
"High-Performance Concrete Carpet" consists of associating a thick and usually cracked base layer with a thin, reinforced high-performance concrete wearing course that does not bond to its support. This pavement may be assumed to be vulnerable to two types of deterioration: buckling of the wearing course during hot weather, and damage due to truck traffic. (Bulletin des Laboratoires des ponts et chaussées, Issue 24-245, p. 15-30.) (Request this item from TIS)

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Safety

Recommendations for Bridge and Tunnel Security
A Blue Ribbon Panel (BRP) of bridge and tunnel experts from professional practice, academia, federal and state agencies, and toll authorities convened to examine bridge and tunnel security and to develop strategies and practices for deterring, disrupting, and mitigating potential attacks. The BRP acknowledges that the nation's bridges and tunnels are vulnerable to terrorist attacks. The intent of this paper is to recommend policies and actions to reduce the probability of catastrophic structural damage that could result in substantial human casualties, economic losses, and socio-political damage. (FHWA Blue Ribbon Panel Report, 64 p.)

Image Processing for Analysis of the Effectiveness of a Reconstruction
The fact that there are no crashes during every three-year period on every part of a road network does not mean that the long-term safety level is exactly zero crashes. What the lack of recorded crashes does mean is that we need less blunt instruments than crash data for evaluating, for example, the effectiveness of a reconstruction. (Nordic Road and Transport Research, Issue 2, 2003, p. 14-15)

Risk, hazard perception and perceived control
This research set out to examine the relationships that exist within a driving context between risk evaluation, perception of hazard, perceived control, and self-induced exposure to risk. (UK Transportation Research Laboratory Report TRL560, 2003, 54 p.)

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Research

Pavement Subgrade Performance Study
The strength or weakness of a pavement structure is based on the performance of the subgrade. The current subgrade failure criteria used in many mechanistic design/evaluation methodologies were surmised mainly from tests that did not consider the effects of subgrade soil type or moisture content. Because of these limitations the current FHWA-sponsored Subgrade Performance Study was designed to investigate and upgrade the failure criteria of subgrade materials. The project plans to study the effect of subgrade type and moisture content on the failure criteria. (US Army Corps of Engineers Cold Regions Research and Engineering Laboratory Report TR-03-5, March 2003, 79 p.)

Will Infrared Thermography Revolutionize Asphalt Paving
Highways throughout the United States are typically engineered to last 15 years and more, but have been failing much earlier due to potholes, cracks, raveling, and other problems. To find out why, a series of research studies of hot-mix asphalt during road construction were launched at the University of Washington, subsequently involving the Washington State Department of Transportation, and the Roadtec subsidiary of Astec, a major manufacturer of infrastructure equipment. The studies determined the cause of premature HMA road failure to be excessive thermal differentials in the hot mix caused by surface and contact cooling during truck transport from the batch plant to the construction site. (Better Roads, December 2003, p. 71-73)

Remote Assessment of Army Tactical River Crossing Sites Using LIDAR Imagery
A crossing site's suitability is highly dependent on riverbank geography. A previous study examined how conventional terrain analysis would be used to determine suitable crossing sites. In that study, there was a 16% acceptable site selection rate for remotely determined crossing sites. This study looks at using a Light Distance and Ranging (LIDAR) digital elevation model (DEM) to improve acceptable site selection rate. LIDAR data were collected at the sites identified in the previous study and inspected to see if the DEM would provide the information and resolution necessary to improve crossing site identification. (US Army Corps of Engineers Cold Regions Research and Engineering Laboratory Report TR-03-11, July 2003, 66 p.)

Finite Difference Procedures for Evaluating the Conduction of Heat and Diffusion of Substances in a Solid Layer or Film
With the advent of the digital computer, complex problems associated with the slow transport of substances and heat by diffusion could be readily solved by finite difference methods. This paper describes the methods used to solve the basic differential equation for diffusion using the examples of heat conduction in a road structure under solar radiation, evaporation of a volatile diluent from a sprayed film of bitumen and the diffusion controlled reaction of atmospheric oxygen with the bitumen films in pavement surfacings. The methods are tolerant of limited changes in the length of the diffusion path with time and two applications where this was used are described. Papers and reports by the author where the methods were applied are referenced. (Road and Transport Research, December 2003, p. 52-60)(Request this item from TIS)

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Structures

Evaluation of a Bridge Deck with CFRP Prestressed Panels Under Fatigue Load Cycles
This report summarizes a study conducted under an IBRC (Innovative Bridge Research and Construction) project sponsored by the FHWA. In this project, a bridge deck with CFRP (carbon fiber reinforced polymeric) prestressed panels and cast-in-place topping slab was designed and constructed by the Colorado Department of Transportation (CDOT) at the I-225 and Parker Road interchange southeast of Denver. To evaluate the performance of the CFRP prestressed deck, an experimental study was carried out on a model deck. (Colorado Department of Transportation Report CDOT-DTD-R-2003-11, September 2003, 134 p.)

Fatigue des câbles de haubanage - Organisation et principaux résultats du programme de recherche dirigé par le LCPC (Cable Fatigue Behavior as a Major Safety Factor in Cable-Stayed Bridges)
This paper presents the organization and results of a research program conducted by the Laboratoire Central des Ponts et Chaussées on the topic of cable fatigue behavior. The research program was organized around four themes: load effects, mechanics, damaging, and tests. (Bulletin des Laboratoires des Ponts et Chaussées, Issue 244-245, p. 53-71)(Request this item from TIS)

Strengthening of Puttesund Bridge by Application of an Independent Stay Cable System
Many countries are facing problems induced by the first generation of cantilever construction method bridges with a hinge in the middle. All these bridges have the same deficiency after a number of years - excessive sagging of the cantilevers with time. This article describes an original solution which consists of lifting the cantilevers by a stay cable system, after placing steel towers at the existing supports. (Routes/Roads, July 2003, p. 30-36)(Request this item from TIS.)

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