Transportation Intelligence

Volume 9 Number 1

Français

February 2011

Administration

Environment

Feedback

Maintenance
Performance-based specification guidelines for the selection of bituminous- based hot-poured crack sealants
The long-term performance of pavements depends in good part on the quality and frequency of maintenance. Appropriate maintenance protects the pavement from deterioration, corrects deficiencies, and ensures safe and smooth riding. Crack sealing is practiced on a routine basis as preventive maintenance and as part of corrective maintenance prior to an overlay or a greater rehabilitation project. A timely and properly installed sealant adds several years of service life to the pavement at a relatively low cost. As a consequence, the selection of an appropriate sealant in a maintenance project becomes an important issue. Current sealant selection is based on ASTM standards that consist of quality control tests, not of performance indicators. These standards do not consider the changes in mechanical properties due to aging or the differences in local service temperatures. The main purpose of this study was to develop a systematic process to help users to select appropriate bituminous hot-poured sealants for pavement cracks and joints. (National Research Council of Canada Institute for Research in Construction report NRCC-53253, January 2009, 39p.)

Winter Maintenance
Optimal Workforce Planning and Shift Scheduling for Snow and Ice Removal
Shrinking budgets and high equipment, fuel, and labor costs have raised the importance of workforce planning and efficient deployment of available workforce for county-level winter maintenance operations. This project focused on developing methodologies for the estimation of workforce requirements, and economic evaluation of the impact of using contract employees, split shifts and staggered shifts. To determine the amount of work induced by different types of storms that occur in Saint Louis County, researchers obtained relevant storm data from a variety of weather reporting sources and extracted parameters relevant for determining plow speeds and sand/salt consumption. These parameters were used to determine optimal workforce deployment strategies that balance overtime and delay costs, which in turn provided estimates of the amount of plowing time needed for the goal of clearing roads within 24 hours after the end of snow fall. (Minnesota Department of Transportation report MN/RC 2011-03, December 2010, 154p.)

Administration (voir aussi Administration)

Feasibility Study Guidelines for Public Private Partnership Projects: Vol I and II
For many state Departments of Transportation (DOTs), a shortage of transportation funds requires the agencies to combat that shortage by implementing innovative programs. Nationwide, Public Private Partnerships (PPP) in transportation projects are increasingly gaining acceptance as an alternative to the traditional approaches of project delivery and public financing. This report presents a framework for PPP feasibility study at the early phase of project development. Three types of PPP models are compared and evaluated to achieve a feasible financing structure. The report includes two volumes: volume I research report and volume II feasibility study guideline. (University of Alabama. University Transportation Center report 930-722R, October 2010, 102p.)

Integrating Pricing into the Metropolitan Transportation Planning Process: Four Case Studies
Road pricing often has come about separate from the traditional metropolitan planning process through pilot projects and demonstrations. This study examined how road pricing was incorporated into long-range planning at four metropolitan planning organizations (MPOs) to provide examples that could support other regions seeking to do the same. The study summarized the experience in the Dallas/Fort Worth region, the Puget Sound region, the Minneapolis/St. Paul region, and the San Francisco Bay area, and identified common themes and differences amongst the approaches used and the outcomes. (US Federal Highway Administration report FHWA-HOP-11-002, September 13, 2010, 60p.)

Public Transportation: Transit Agencies' Actions to Address Increased Ridership Demand and Options to Help Meet Future Demand
Demand for public transportation in the United States reached record highs in 2008 and rose in the decade prior to 2008. Increased demand for public transportation can create opportunities and challenges for communities working to meet demand, improve service, and maintain transit systems, while operating within budgetary constraints. This report addresses (1) trends in transit ridership and services from 1998 through 2008, (2) challenges, if any, transit agencies faced during this period to address increased ridership and actions they took in response, and (3) factors that might affect future ridership demand and the ability of transit agencies to meet that demand. (US Government Accountability Office Report GAO-11-94, November 2010, 64p.)

Back to Top

Materials (voir aussi Matériaux)

Evaluation of Self-Consolidating Concrete (SCC) for Use in North Dakota Transportation Projects
The purpose of this research project is to evaluate self-consolidating concrete (SCC) for use in North Dakota transportation projects. To gain a better understanding of SCC properties, there is an immediate need for a comprehensive evaluation of the technology under North Dakota conditions and the development of construction specifications. Therefore, SCC will be evaluated and suggested acceptance criteria will be established. It is anticipated that the findings of the investigation will serve as a significant progress in the application of SCC in the North Dakota transportation projects. (North Dakota Department of Transportation report, June 8, 2010, 222p.)

Advanced High-Performance Materials for Highway Applications: A Report on the State of Technology
This report reviews new and improved highway construction materials and technologies, identifying materials that can improve highway performance, replace scarce or unavailable natural materials, and contribute to more sustainable highways. The materials and processes identified have all either been introduced within the past 5 years and are not yet widely used or are still in development. They included advances in cements, concretes, asphalt binders, asphalts, metallics and polymers, aggregates, and other materials. Also included are materials that reduce noise, improve smoothness, allow for faster placement and shorter construction times, reduce energy consumption, capture CO2, and lower costs. For each material, the report provides a description, applications, benefits, costs, current status, and sources of additional information. (US Federal Highway Administration report FHWA-HIF-10-002, September 2010, 69p.)

Validating the Durability of Corrosion Resistant Mineral Admixture Concrete
The objectives of this research are to validate chloride diffusion coefficients of mineral admixture concrete mix designs currently developed by the Caltrans for corrosion mitigation, and to verify the adequacy of existing measures to mitigate corrosion caused by exposure to marine environments and deicing salt applications. To this end, this research includes a comprehensive literature review on relevant topics, a laboratory investigation and a modeling effort. (California Department of Transportation Report, December 2010, 179p.)

Back to Top

Traffic Control (voir aussi Gestion de la circulation)

Accessible Pedestrian Signals: A Guide to Best Practices (Workshop Edition 2010)
This report provides an introduction to accessible pedestrian signals (APS) and highlights issues related to the design, installation, operation, and maintenance of APS. The report also addresses public education, U.S. case studies, and international practice related to APS. In addition, the report explores issues related to travel by pedestrians who are blind or who have low vision, and examines traffic signals and modern intersection design. NCHRP Web-Only Document 150 is designed to serve as a companion resource document to a one-day training course on accessible pedestrian signals. (TRB National Cooperative Highway Research Program (NCHRP) web-only document 150, 2010, 339p.)

Effectiveness of transverse road markings on reducing vehicle speeds
Transverse road markings as a speed mitigation device may be a cost-effective method of reducing fatal and serious injury crashes as a consequence of speeding on a high-speed hazard approach. As no established marking layouts have been formally applied in New Zealand, investigations into the use and application of transverse road markings have been conducted over 2008 2010. The culmination of this research was to develop and undertake two field trials on the New Zealand State Highway network. The field trials assessed vehicle speed in a before-and-after study. (New Zealand Transport Agency research report 423, October 2010, 72p.)

Effects of Red Light Camera Enforcement on Fatal Crashes in Large US Cities
From the 99 large US cities with more than 200,000 residents in 2008, 14 cities were identified with red light camera enforcement programs during 2004-08 but not during 1992-96, and 48 cities were identified without camera programs during either period. Analyses compared the citywide per capita rate of fatal red light running crashes and the citywide per capita rate of all fatal crashes at signalized intersections during the two study periods, and rate changes then were compared for cities with and without cameras programs. Poisson regression was used to model crash rates as a function of red light camera enforcement, land area, and population density. (US Insurance Institute for Highway Safety report, February 2011, 18p.)

Development and Field Demonstration of DSRC-Based V2I Traffic Information System for the Work Zone
This report describes the architecture, functionality and the field demonstration of a newly developed dedicated short range communication (DSRC)-based Vehicle to Infrastructure (V2I) communication system for improving traffic efficiency and safety in the work-zone related congestion buildup on US roadways. The goal was to develop a portable system that can be easily deployed at a work zone site to acquire and communicate important travel information, e.g., travel time (TT) and start of congestion (SoC) location to the driver. By providing this information, i.e., SoC location and TT, drivers can make informed decisions on route choice and be prepared for upcoming congestion. (University of Minnesota Center for Transportation Studies report CTS 10-15, December 2010, 46p.)

Development of Algorithms for Travel Time-Based Traffic Signal Timing, Phase I - A Hybrid Extended Kalman Filtering Approach for Traffic Density Estimation along Signalized Arterials
As technologies continue to mature, the concept of IntelliDrive has gained significant interest. Besides its application on traffic safety, IntelliDrive also has great potential to improve traffic operations. If the trajectories of a small percentage of vehicles (IntelliDrive vehicles) can be measured in real time, how can we use such data to improve traffic management? This research serves as a starting point that aims to optimize the traffic signal control from the use of the conventional fixed-point loop detector data to the use of mobile vehicle trajectory-based data. (University of Minnesota Center for Transportation Studies report CTS10-10, December 2010, 38p.)

Back to Top

Environment (voir aussi Environnement)

Developing a Framework for a Toolkit for Carbon Footprint that Integrates Transit (CFIT)
The purpose of this research was to evaluate five transportation planning processes used in Florida to determine how greenhouse gas (GHG) emissions considerations can be incorporated into the processes. The research included a review of GHG emissions calculation tools and their applicability to each planning process. The research also included four case studies from the states of New York, California, Washington and Massachusetts, featuring proposed transportation improvement projects and programming of varying scales and how GHG emissions were calculated and were figured into decision making. The study also included the development of a scenario of a public bus transit improvement project that was used in calculating an estimate of generated GHG emissions. (Florida Department of Transprtation report, November 2010, 203p.)

Assessing Air Quality Impacts of Managed Lanes
Impacts on transit bus performance and air quality were investigated for a case study high-occupancy/toll (HOT) lane project on a corridor of I-95 near Miami. Trends in air pollutant concentration monitoring data in the study area were first analyzed. Traffic movement prior to and after implementation of the HOT lanes was simulated using corridor micro-simulation (CORSIM). Emissions of carbon monoxide, nitrogen oxides, particulate matter, hydrocarbons, and benzene were estimated using MOBILE6.2. Finally, changes in ambient pollutant concentrations were estimated using AERMOD dispersion simulations. (Florida Department of Transportation report FDOT-BDK85-TWO #977-11, December 2010, 71p.)

Back to Top

Safety (voir aussi Sécurité)

Advanced LED Warning Signs for Rural Intersections Powered by Renewable Energy
A majority of intersection-related fatal crashes occur at rural, through/stop intersections. At these intersections, sight restrictions caused by vertical and horizontal curves negatively affect a driver's ability to safely accept a gap in the traffic stream. A new Advanced Light-Emitting Diode (LED) Warning System was developed and deployed at a rural, through/stop intersection with limited intersection sight distance due to a severe vertical curve. This warning system actively detects vehicles on all approaches and activates LED blinker warning signs for the conflicting movements. The research project included analysis of driver behavior obtained through video data and a survey of local residents and frequent users of the intersection. This report describes the development, implementation, and evaluation results of this new warning system. (Minnesota Department of Transportation report MN/RC 2011-04, December 2010, 101p.)

Crosswalk Marking Field Visibility Study
The objective of this study was to investigate the relative daytime and nighttime visibility of three crosswalk marking patterns: transverse lines, continental, and bar pairs. In general, this study collected information on the distance from the crosswalk at which the participant verbally indicated its presence. The 78 participants were about evenly divided between groups of male and female participants and between groups of younger (younger than 55 years old) and older (55 years old or older) participants. Data were collected during two periods: daytime (sunny and clear or partly cloudy) and nighttime (street lighting on). Existing markings (six intersection and two midblock locations) and new markings installed for this study (nine midblock locations) were tested. (US Federal Highway Administration report FHWA-HRT-10-068, November 2010, 120p.)

Effects of roundabouts on road casualties in the Netherlands
This study evaluates the effects on road crash casualties and takes into consideration all crashes on all known roundabouts built in the Netherlands during the period of 1999 to 2005, not just a sample. Before and after crash and roundabout information is used and specific attention is paid to fatalities and (police reported) serious road injuries. The report also contains a cross-section comparison of road junctions and roundabouts. (SWOV Institute for Road Safety Research report R-2010-21, 2010, 48p.)

Promoting CenterLine Rumble Strips to Increase Rural, Two-Lane Highway Safety
Centerline Rumble Strips (CLRS) are primarily installed on the centerline of undivided, two lane, two-way highways, and their main purpose is reduction of crossover accidents, specifically head-on and opposite direction sideswipe accidents. Some concerns involving CLRS, such as disturbing noise for nearby residents, decreased visibility of the painted strips, faster pavement deterioration, potential driver erratic maneuvers to the left after encountering CLRS, and ice formation in the grooves, have been cited in the current literature. The objective of this report is to summarize results of three studies conducted by Kansas State University in 2008 and 2009; addressing some of the above mentioned concerns related to the installations of CLRS. (Kansas Department of Transportation report KSU-08-3, December 2010, 85p.)

Model Inventory of Roadway Elements - MIRE, Version 1.0
Safety data are the key to sound decisions on the design and operation of roadways. Critical safety data include not only crash data, but also roadway inventory data, traffic data, driver history data, citation/adjudication information, and other files. The need for improved and more robust safety data is increasing due to the development of a new generation of safety data analysis tools and methods. The Model Inventory of Roadway Elements (MIRE) Version 1.0 is a listing and accompanying data dictionary of roadway and traffic data elements critical to safety management. It builds upon the initial minimum MIRE listing released in 2007. A MIRE website has been developed to provide additional background information, resources, and discussion Forums. The website is available at http://www.mireinfo.org/. (SWOV Institute for Road Safety Research report R-2010-21, 2010, 48p.)

Impacts of low speed vehicles on transportation infrastructure and safety
There are increasing numbers of low-speed electric vehicles (LSVs) on public roadways. These vehicles are designed to be used within protected environments and on roadways with a maximum posted speed of 25 mph. Currently these vehicles are not subject to the same federal requirements for occupant protection as passenger cars. This research project investigated safety standards, operating regulations, and LSV manufacturer materials from sources around the world. The purpose of the research was to determine positive and negative impacts that LSVs are likely to have for the Oregon Department of Transportation (ODOT) and Oregon communities. (Oregon Transportation Research and Education Consortium (OTREC) report OTREC RR-10-19, December 2010, 60p.)

Back to Top

Structures (voir aussi Ouvrages d'art)

Evaluation of Thin Overlays for Bridge Decks
Eight thin polymer overlay systems were evaluated in the laboratory and on two bridge decks exposed to trucks and passenger vehicles including those with studded tires. None of the overlay systems showed superior performance under moderate average daily traffic from the standpoint of maintaining good skid resistance and resisting wear through. For the five products that did not wear through, empirical equations predicted the friction number of the best of these five products would decrease to 40 (equivalent to the friction number of the concrete) within five months at a traffic level of 10,000 vehicles per lane per day. Delamination from the concrete was not a major problem with the products. Laboratory tests were not able to predict performance. (Oregon Department of Transportation report FHWA-OR-RD-11-05, November 2010, 78p.)

Bridge Approach Slabs for Missouri DOT: Looking at Alternative and Cost Effective Approaches
The objective of this project is to develop innovative and cost effective structural solutions for the construction of both new and replacement deteriorated Bridge Approach Slabs (BAS). A cost study and email survey was performed to identify states whose BAS are lower in costs compared to Missouri and perform adequately. (Missouri Department of Transportation report OR11-009, December 2010, 251p.)

Back to Top