TAC Transportation Intelligence

Maintenance
Pavement Rehabilitation Selection
The objective of the project was to outline best practices for the selection of asphalt pavement recycling techniques from the many choices that are available. The report specifically examines cold-in-place recycling (CIR), plain full depth reclamation (FDR), and mill & overlay (M&O). Interviews, surveys, and site visits were conducted at both Mn/DOT districts and counties, where relevant rehabilitation information was supplied on over 120 projects. A database was constructed to organize the details of these projects, and the parameters in the database included (1) cracking, (2) ride, (3) rutting, (4) age, and (5) traffic volume. From studying the existing rehabilitation projects in the State, Ride Quality Index (RQI) and Surface Rating (SR) were selected as the descriptors of pavement surface condition. A decision procedure based on the analysis of all available projects was developed. The decision procedure included (1) consideration of road geometrics; (2) pavement condition survey; and (3) structural adequacy evaluation. Furthermore, a step-by-step checklist was developed to provide local engineers with a simple and useful tool to follow the decision procedures. The procedure includes selection of rehabilitation method, pavement thickness design, materials mixture design, and construction. (Minnesota Department of Transportation Report Mn/DOT 2008-06, January 2008, 143 p.)

Construction
Nighttime Construction: Evaluation of Lighting Glare for Highway Construction in Illinois
This report presents the findings of a research project that studied the veiling luminance ratio (glare) experienced by driveby motorists in lanes adjacent to nighttime work zones. The objectives of the project are to (1) provide an in-depth comprehensive review of the latest literature on the causes of glare and the existing practices that can be used to quantify and control glare during nighttime highway construction; (2) identify practical factors that affect the measurement of veiling luminance ratio (glare) in and around nighttime work zones; (3) analyze and compare the levels of glare and lighting performance generated by typical lighting arrangements in nighttime highway construction; (4) evaluate the impact of lighting parameters on glare and provide practical recommendations to reduce and control lighting glare in and around nighttime work zones; (5) develop a practical model to measure and quantify levels of glare experienced by drive-by motorists; and (6) investigate and analyze existing studies and recommendations on the maximum allowable levels of veiling luminance ratio (glare) that can be tolerated by nighttime drivers. (Illinois Center for Transportation Report FHWA-ICT-08-014, January 2008, 206 p.)

Administration
Lost & Found: A Smart-Practice Guide to Managing Organizational Memory
Crucial knowledge and experience are being lost within the Public Service of Canada due to retirements, organizational change, and shifts in personnel. The guide you are holding addresses that challenge by offering strategic insights and useful advice about smart-practices that combat organizational memory loss. Individuals and organizations within the Public Service can use this guide to help preserve the core knowledge that is critical to achieving results. (Canada School of Public Service research paper, 2007, 52 p.)

Planning

Understanding How to Motivate Communities to Support and Ride Public Transportation
This report provides a comprehensive discussion on the methods and strategies used by public transportation agencies in the United States and Canada to enhance their public images and motivate the support and use of public transportation. This report will be helpful to transit agencies; elected officials; community leaders; business leaders; and federal, state, and local funding agencies in both the United States and Canada. (TRB Transit Cooperative Research Program Report 122, 2008, 89 p.)

Guidebook for Measuring, Assessing, and Improving Performance of Demand-Response Transportation
This report will be of interest to public transportation systems that provide demand-response transportation (DRT) services and to the communities they serve. The Guidebook is a resource to assist DRT systems to measure, assess, and improve their performance. This Guidebook focuses on DRT in urban areas. (TRB Transit Cooperative Research Program Report 124, 2008, 131 p.)

Estimation and Evaluation of Transportation Costs
Cost data for the construction and operation of facilities are essential for the evaluation of infrastructure services supplied by private or public providers. This roundtable examines what data is needed for evaluation; which methods best measure the efficiency of service provision and benchmark providers; how regulatory regimes impact costs; and how regulators can counter the asymmetry of information as well as the incentive for data providers to selectively serve business rather than user interests. (European Conference of Ministers of Transport Round Table 136, 2007, 134 p.)(To borrow this item, please contact the TIS.)

Airport Ground Access Mode Choice Models
The prediction of air passenger and airport employee mode choice decisions for travel to and from the airport forms a key analytical component of airport landside planning, as well as airport system planning. However, there is currently no generally accepted and validated approach to modeling how airport users will change their access or egress mode in response to changes in the airport ground transportation system. This report has been undertaken to update and extend previous efforts to document the state of practice for airport ground access mode choice models. It examines the characteristics of existing models and discusses the issues involved in the development and use of such models, as well as research and development efforts that are needed to improve the state of the art of modeling airport ground access mode choice and address technical issues that are not currently well handled. (Transportation Research Board Airport Cooperative Research Program Synthesis 5, 2008, 151 p.)

Default Values for Highway Capacity and Level of Service Analyses
Based on the assembly of an extensive set of field data from across the United States, this report presents valuable information on the appropriate selection of default values when analyzing highway capacity and level of service. The report will be useful to planners, geometric designers, and traffic engineers who do not have ready access to field data for an analysis. The report also describes how to prepare service volume tables, which can be a useful sketch planning technique. (TRB National Coopertive Highway Research Program Report 599, 2008, 132 p.)

Papers Presented - First International Conference on Funding Transportation Infrastructure
This conference will focus on the relationship between pricing of transportation infrastructure and investments. It will consider institutional mechanisms such as earmarking of revenues, transportation funds, Public Private Partnerships, and inter-government relationships that facilitate (or potentially impede) efficient pricing and investment decisions for transportation infrastructure. The conference is targeted at researchers, industry practitioners and policymakers. Theoretical, empirical/case-study and policy-oriented contributions are all welcome. (First International Conference on Funding Transportation Infrastructure, 2-3 August, 2006.)

Véhicules plus longs et plus lourds: rapport final (Longer, Heavier Vehicles – Final Report)
This report provides the findings of the <<Longer, heavier véhicles>> (LHV) Working Group assembled by the Roadways Research Centre (Centre de recherches routières - CRR) in 2005, at the request of roadway infrastructure management authorities. The rapid growth and rising demand for the transportation of goods on European highways will bring increased levels of pollution, energy consumption and congestion. In light of this, authorities have undertaken to gain more knowledge on various ramifications of using longer, heavier vehicles, particularly as it pertains to their possible introduction in Belgium. The report includes a description of LHVs and provides an overview of related legislation and a summary of recent European experiences with this type of vehicle, namely in Sweden, Finland, the Netherlands and Germany. It also describes their potential effects on mobility, the economy, infrastructure, the environment and safety, followed by a review of the social and fiscal aspects of LHV use. It concludes with a list of summary findings and the working group’s draft statement of position. (Belgique - Centre de recherches routieres publication F 44/07, 2007, 148 p.)(To borrow this item, please contact the TIS.)

Safety

Safety Effects of Left-Turn Phasing Schemes at High-Speed Intersections
This report describes an effort in estimating crash modification factors (CMFs) associated with different left-turn phasing schemes, at intersections where the major approach speed limit exceeds 40 mph. This report also describes a simple simulation model for left-turn cross-path crashes, where a probabilistic gap acceptance model for the turning driver is combined with a standard braking model for the opposing driver. (Minnesota Department of Transportation Report MN/RC-2007-03, January 2007, 69 p.)

Passing Sight Distance Criteria
This report presents recommendations on the adequacy of current procedures and guidelines used to estimate minimum passing site distance (PSD) requirements for highway design and pavement marking. The research involved a review of current practice, an extensive analysis of various alternative PSD models, and field studies of passing maneuvers on two-lane highways. The report includes specific text recommended for inclusion in the next edition of the AASHTO A Policy on Geometric Design of Highways and Streets (the “Green Book”). The report will be of interest and value to all users of the current design and pavement marking guides to apply the best available knowledge on passing sight distance requirements. (Transportation Research Board National Cooperative Highway Research Program Report 605, 2008, 95 p.)

Safety Evaluation of Flashing Beacons at Stop-Controlled Intersections
The goal of this research was to evaluate and estimate the effectiveness of flashing beacons at stop-controlled intersections as one of the strategies in the Evaluation of Low-Cost Safety Improvements Pooled Fund Study (ELCSI-PFS), Phase I. This research provides Crash Reduction Factor (CRF) and economic analysis for the effectiveness of flashing beacons at stop controlled intersections strategy. The estimate of effectiveness for flashing beacons at stop-controlled intersections strategy was determined by conducting scientifically rigorous before-after evaluations at sites where this strategy was implemented in the United States. (US Federal Highway Administration report FHWA-HRT-08-044, December 2007, 38 p.)

Injury accidents with bicyclists at roundabouts : influence of the design of cycle facilities and other location characteristics
In a previous study, the authors performed a before-and-after analysis of injury crashes with bicyclists at roundabouts (Daniels et al., 2007). However, some questions stayed open after the study. Considerable differences between countries seem to exist in the applied road design in order to conduct bicyclists through roundabouts. The main research question in this study was to investigate possible differences between designs for cycle facilities regarding safety for bicyclists. This article describes the results of analyses based on additionally collected information about the design type of the cycle facilities and some geometrical features of the investigated roundabouts. (Mobiliteit en openbare werken report RA-MOW-2008-001, 2008, 27 p.)

Crash Patterns and Potential Engineering Countermeasures at Maryland Roundabouts
Each year in the United States more than 1.2 million injuries and 9,000 deaths occur in motor vehicle crashes at intersections. Previous research has found that construction of roundabouts in place of traditional intersections can decrease crash frequency and severity. Despite these safety benefits, some crashes still occur at roundabouts. The present study reviewed police crash reports for a set of roundabouts in Maryland to develop a typology of crashes and identify potential countermeasures. The review included 149 crashes at 29 single-lane roundabouts and 134 crashes at 9 double-lane roundabouts. (US Insurance Institute for Highway Safety report, May 2008, 21 p.)

Winter Maintenance Improvements: Phase 1
The main goal of the project was to evaluate mechanical, electronic and optical means of improving the visibility of the snowplow operator as well as the snowplow vehicle to other motorists on the road. After a survey of various technologies the research team implemented and tested the following methods of visibility improvement. (1) Radar-based collision warning system to give visual and audio warnings of vehicles detected in the path of the snowplow vehicle that the snowplow operator might not see due to poor visibility conditions. (2) Vehicle mounted airfoil that modifies the pressure zone behind the snowplow vehicle to reduce the amount of swirling snow particles building up on the rear lights and surface of the snowplow vehicle. (3) Air blower system that may help decrease density of the falling snow in front of the snowplow vehicle in order to improve the operator’s field of vision. (4) Investigating different types of warning lights as well as their configuration and determining which combinations were the most visible by other motorists during snowplowing operations. (5) Tail light puffer system that channels air from the snowplow vehicle’s compressor to the rear tail lights in order to clear away built up snow. (Nevada Department of Transportation Report RTD08-001, April 2008, 67 p.)

Informational Report on Lighting Design for Midblock Crosswalks
This report provides information on lighting parameters and design criteria that should be considered when installing fixed roadway lighting for midblock crosswalks. The information is based on static and dynamic experiments of driver performance with regard to the detection of pedestrians and surrogates in midblock crosswalks. Experimental condition variables included lamp type (high-pressure sodium and metal halide), vertical illuminance level, color of pedestrian clothing, position of the pedestrians and surrogates in the crosswalk, and the presence of glare. Two additional lighting systems, a Probeam luminaire and ground-installed LEDs, were also evaluated. The research found that a vertical illuminance of 20 lx in the crosswalk, measured at a height of 1.5 m (5 ft) from the road surface, provided adequate detection distances in most circumstances. Although the research was constrained to midblock placements of crosswalks, the report includes a brief discussion of considerations in lighting crosswalks colocated with intersections. (US Federal Highway Administration Report FHWA-HRT-08-053, April 2008, 27 p.)

Star Rating School Walking Routes
It has become a community health priority to introduce some of the benefits of walking to primary school children by encouraging active transport to and from school. Consequently, it is vitally important to ensure that children are able to walk safely, with one of the biggest threats being the potential for injury at road crossing points. A general method for rating the safety of individual road crossing points was devised, based on the 'star rating' concept familiar to many modern consumers of products and services. A model was developed that considered the main determinants of pedestrian crash and injury risk at a specified road crossing then, based on established relationships and expert consensus, mathematically combined them to generate a star rating between zero and five for each croossing point along a route. While the model is designed primarily for crossing points while recognizing the abilities and limitations of children, it is intended to be generic in its application, subject to appropriate internal modifications. (Monash University Accident Research Centre Report 275, May 2008, 2 p.)

Pavements

Performance-Related Tests of Recycled Aggregates for Use in Unbound Pavement Layers
This report contains recommendations for performance-related procedures to test and select recycled hot-mix asphalt (HMA) and portland cement concrete (PCC) materials for use in unbound layers of highway pavements. The report provides a comprehensive description of research intended to help materials engineers evaluate and select the reclaimed asphalt (RAP) and reclaimed concrete pavement (RCP) materials that should contribute to good performing pavements. Also, the report describes procedures for the recommended tests. The contents of this report will be of immediate interest to materials engineers, researchers, and others concerned with the construction and performance of asphalt and PCC pavements. (TRB National Cooperative Highway Research Program Report 598, 2008, 61 p.)

Pavement Management Systems Peer Exchange Program Report
This report summarizes the use of pavement management tools to support agency decisions in the Utah Department of Transportation (UDOT) and Minnesota Departmet of Transportation (Mn/DOT), provides tips for procuring new pavement management software, and identifies institutional issues that must be addressed to make the most of a pavement management program. It closes with a summary of the key factors influencing the successful pavement management practices in UDOT and Mn/DOT. (US Federal Highway Administration report, May 2008, 42 p.)

Improved Life for Longitudinal Joints in Asphalt Pavement
The Wisconsin Highway Research Program (WHRP) Flexible Pavements Technical Oversight Committee requested a synthesis report on recent research and practices aimed at improving the performance lives of longitudinal joints in asphalt pavements. This report first looks at the current WisDOT Approach to establish a baseline, then review research and guidelines regarding Joint Design, and then look at research devoted to proper Compaction and Density of HMA at the joint. Following this section we consider Construction and Specifications, documents that detail best construction approaches and that look at the development of a joint density specification to ensure proper construction. This report also looks at recommendations and research from a few states on the use of Sealants to prevent or mitigate joint failure, and reviews the use of a field permeameter for Quality Control. Finally, we review the Research in Progress that five agencies are conducting on these topics. (Wisconsin Department of Transportation report, 1 May 2008, 7 p.)

Evaluation of Long-Term Pavement Performance and Noise Characteristics of Open-Graded Friction Courses
This experimental project is being conducted as a part of WSDOT’s effort to produce pavements that reduce the noise generated at the tire/pavement interface. Experimental sections of open-graded friction courses (OGFC) were built using asphalt rubber (AR) and styrene-butadiene-styrene (SBS) polymer modified asphalt binders. A section of conventional Class ½ inch hot mix asphalt (HMA) serves as the control section for the two experimental sections. Sound intensity measurements were conducted using the On Board Sound Intensity (OBSI) method immediately after construction and monthly, weather permitting, for a year following construction. (Washington State Department of Transportation Report WA-RD 683.1, March 2008, 98 p.)

Exploring Alternative Strategies for the Rehabilitation of Low-Volume Roads in Nevada
The Nevada Department of Transportation (NDOT) is faced with the challenge of how to balance its available funding between pavement preservation and capacity improvement projects. This challenge is even greater for the low-volume roads network. Thus, more cost-effective methods for pavement rehabilitation and maintenance must be determined and evaluated for inclusion in NDOT’s pavement preservation program. A total of 29 combinations of pavement surface and structural rehabilitation strategies were constructed on 111 centerline miles of low-volume roads throughout Nevada. The strategies included full depth reclamation, cold mix asphalt concrete pavement, cold in-place recycling, and various surface treatments. The test sections were monitored with roughness surveys, condition surveys, falling weight deflectometer testing, and core evaluations for resilient modulus, strength, and rutting susceptibility. The primary deliverable was proposed low-volume roads rehabilitation guidelines. The guidelines were based on whether the pavement exhibits structural or functional deficiencies. The guidelines provide systematic and cost-effective alternatives for pavement managers when tasked with choosing among rehabilitation options. (Nevada Department of Transportation Report NV-RDT-08-001, January 2008, 106 p.)

Enrobés à module élevé (EME): de la conception à la mise en oeuvre (High Modulus Asphalt (HMA): From Design to Placement)
This research summary describes a project undertaken in the search for solutions to rutting problems occurring on heavily used Belgian roads. Tests conducted in other countries have shown that HMA (High Modulus Asphalt) provides excellent total life cycle results in response to binder course issues (rutting, cracking, etc.) encountered on heavily loaded roadways. The purpose of this research project was to test the feasibility of this solution under typical Belgian conditions and to acquire the knowledge and experience required for the proper formulation, production and placement of HMA. (Belge - Centre de recherches routieres publication (CR) 43/07, 2007, 196 p.) (To borrow this item, please contact the TIS.)

Environment

UDOT Wildlife and Domestic Animal Accident Toolkit
Since the original report, WILDLIFE & DOMESTIC ANIMAL-VEHICLE COLLISIONS, was published much of the data contained therein was in need of being updated. This report, titled UDOT WILDLIFE AND DOMESTIC ANIMAL ACCIDENT TOOLKIT, contains some updates of the data plus more information regarding wildlife and domestic animal accident hotspots has been added, including updated accident data and wildlife connectivity data taken from the report, WILDLIFE CONNECTIVITY ACROSS UTAH’S HIGHWAYS – UPDATED. Additionally, more toolkit information has been added to give project managers, planners, design engineers, etc., more tools to work with to help keep animals off the rights-of-way and roadways. (Utah Department of Transportation Report, 29 April 2008, 66 p.)

Recycling of Salt-Contaminated Stormwater Runoff for Brine Production at Virginia Department of Transportation Road-Salt Storage Facilities
A large part of the Virginia Department of Transportation’s (VDOT’s) maintenance effort comprises the implementation of its snow removal and ice control program. Although VDOT is implementing recommended management options to reduce the quantity of salt water captured, this research was undertaken to determine the possibility of recycling salt-contaminated stormwater runoff for the purpose of producing brine that can be used for pre-wetting of granular NaCl and direct application. (Virginia Transportation Research Council Report VTRC 08-R17, May 2008, 26 p.)

Development of a Comprehensive Modal Emissions Model
In August 1995, the College of Engineering-Center for Environmental Research and Technology (CE-CERT) at the University of California-Riverside and researchers from the University of Michigan and Lawrence Berkeley National Laboratory, began a four-year research project to develop a Comprehensive Modal Emissions Model (CMEM). The overall objective of the research project was to develop and verify a modal emissions model that accurately reflects Light-Duty Vehicle (LDV, i.e., cars and small trucks) emissions produced as a function of the vehicle.s operating mode. The model is comprehensive in the sense that it is able to predict emissions for a wide variety of LDVs in various states of condition (e.g., properly functioning, deteriorated, malfunctioning). The model is now complete and capable of predicting second-by-second tailpipe emissions and fuel consumption for a wide range of vehicle/technology categories. (TRB's National Cooperative Highways Research Project web-only report 122, 2000, 435 p.)

Traffic Control

Public Opinion and Understanding of Advance Warning Arrow Displays Used in Short-Term, Mobile, and Moving Work Zones
In long-term work zones on multilane highways and/or freeways, the Federal Highway Administration has interpreted the Manual on Uniform Traffic Control Devices to mean that only one advance warning arrow display can be used to denote the closure of a single lane. Where two or more lanes are closed, a single arrow display is used for each lane to be closed. However, in short duration, mobile, and moving work convoys the MUTCD allows the use of multiple arrow displays to indicate a single lane closure. These disparate uses for arrow displays create the potential for confusion by drivers. This paper describes the results of four focus group interviews with Midwestern drivers. Participants were shown several mocked images of shadow work vehicles with arrow displays and were questioned on how well they understood and/or interpreted the message conveyed by arrow displays depending on the display type and quantity of displays used, and looked specifically for potential driver confusion. (University of Kansas Technical Report 45110-1, March 2008, 43 p.)

Advancing Durable Pavement Marking Materials in Nevada
The durability of pavement markings was identified as an operational issue in all the Nevada Department of Transportation (NDOT) maintenance districts. Thirty pavement marking products were applied and evaluated on five test sites in Nevada. The materials included waterbourne, polyurea, epoxy, alkyd thermoplastic, and permanent tape products. Test sections consisted of edge and centerline application that varied in length from 0.15 to 3 miles long. The test sections were monitored for retroreflectivity, color, and durability data. (Nevada Department of Transportation report RDT06-01, December 2005, 160 p.)

Transportation Intelligence

Volume 6 Number 3

June 2008

Structures

Planning

Safety

Pavements

Environment

Traffic Control

Feedback

Structures

Planning

Safety

Pavements

Environment

Traffic Control