Transportation Intelligence

Volume 6 Number 2

April 2008

Urban

Safety

Pavements

Environment

Traffic Control

Feedback

Maintenance
Bridge Inspection Practices
This synthesis reports on bridge inspection practices in the United States and selected foreign countries. Specifically, it is a collection of information on formal inspection practices of departments of transportation (DOTs). For U.S. inspection practices, information is presented on inspection personnel (staff titles and functions, qualifications, training and certification, inspection teams, and the assignment of teams to bridges), inspection types (focus, methods, and frequency), and inspection quality control and quality assurance by the DOT inspection programs. Foreign practices are also presented according to inspection personnel, types, and quality programs. Also examined are uses agencies make of information gathered from bridge inspections, what triggers repairs, and plans for future development of inspection programs. Information from Canadian sources can be found in Appendix C. (TRB's National Cooperative Highway Research Program Synthesis 375, 2008, 209 p.)

Administration
Highway Public-Private Partnerships: More Rigorous Up-front Analysis Could Better Secure Potential Benefits and Protect the Public Interest
GAO was asked to review (1) the benefits, costs, and trade-offs of public-private partnerships; (2) how public officials have identified and acted to protect the public interest in these arrangements; and (3) the federal role in public-private partnerships and potential changes in this role. GAO reviewed federal legislation, interviewed federal, state, and other officials, and reviewed the experience of Australia, Canada, and Spain. GAO’s work focused on highway-related public-private partnerships and did not review all forms of public-private partnerships. (US Government Accountability Office (GAO) Report GAO-08-044, February 2008, 96 p.)

Manual on Use of Self-Propelled Modular Transporters to Remove and Replace Bridges
This manual contains information on the equipment, benefits, costs, project selection criteria, planning, design, contracting issues, and example contract documents for using self-propelled modular transporters to move bridges. It also includes case studies and lessons learned from previous projects. The manual is intended for use by bridge owners, construction contractors, suppliers, and other professionals involved in bridge design and construction. (US Federal Highway Administration Report FHWA-HIF-07-022, June 2007, 118 p.)

Urban

Advanced Network Planning for Bus Rapid Transit: The “Quickway” Model as a Modal Alternative to “Light Rail Lite”
Transit planning in the United States has tended toward viewing BRT as an analogue to light rail transit, with similar operating patterns. This model, referred to as “Light Rail Lite,” is compared to international best practices, which have often favored the development of a grade-separated bus infrastructure (“Quickways”) that in turn supports a varied mix of all-stops, express, and branching services. The two models are contrasted along the key dimensions of BRT service, and significant differences are identified. Three international case studies—Ottawa, Bogotá, and Brisbane—are reviewed for their particular application of this model and of the results they have obtained. Four domestic cities are compared to these international examples. (National Bus Rapid Transit Institute report, February 2008, 116 p.)

Growing Neighborhoods in Growing Corridors: Land Use Planning for Highway Noise
This document aims to provide technical asssistance to local authorities that wish to consider noise as an integral part of land use planning decisions. It provides tools to help local planning staffs and policy makers consider noise impacts as a routine part of their development regulations and review processes. Local decision makers are likely to become increasingly responsible for noise impacts arising from land use decisions. (Montana Department of Transportation report FHWA/MT-08-002/8117-36, March 2008, 52 p.)

Resident's Guide for Creating Safe and Walkable Communities
This guide is intended to assist residents, parents, community association members, and others in getting involved in making communities safer for pedestrians. The guide includes facts, ideas, and resources to help residents learn about traffic problems that affect pedestrians and find ways to help address these problems and promote pedestrian safety. The guide includes information on identifying problems, taking action to address pedestrian concerns, finding solutions to improve pedestrian safety, and resources to get additional information. (US Federal Highway Administration Report FHWA-SA-07-016, February 2008, 79 p.)

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Safety

Techbrief: Safety Evaluation of Center Two-Way Left-Turn Lanes on Two-Lane Roads
The purpose of the study is to evaluate the safety effectiveness of center two-way left-turn lanes (TWLTLs) on two-lane roads. This strategy is intended to reduce the frequency of head-on crashes and rear-end crashes involving a turning vehicle. The safety effectiveness of this strategy has not been thoroughly documented previously; therefore, this study is an attempt to provide an evaluation of TWLTLs through scientifically rigorous procedures. (US Federal Highway Administration Technical Brief number FHWA-HRT-08-046, March 2008, 6 p.)

Techbrief: Safety Evaluation of STOP AHEAD Pavement Markings
The purpose of the study is to evaluate the safety effectiveness of STOP AHEAD pavement markings. STOP AHEAD pavement markings are intended to reduce the frequency of crashes related to lack of driver awareness of stop control at unsignalized intersections. The safety effectiveness of this strategy had not previously been thoroughly documented; therefore, this study attempts to provide an evaluation of STOP AHEAD pavement markings through scientifically rigorous procedures. (US Federal Highway Administration Technical Brief FHWA-HRT-08-045, March 2008, 6 p.)

Traffic Safety Methodologies
The main objective of this research was to review how, and to what extent, safety issues are treated in context-sensitive design activities. The ideal to which we refer is that safety issues should be an explicit and quantitative component of design decision-making. This means that ideally, numerical predictions of the safety effects of different design alternatives should be part of how those alternatives are evaluated. Because a review of safety in all its aspects is beyond the scope of this project, we focused on pedestrian safety and its relation to traffic-calming design elements. (University of Minnesota Center for Transportation Studies report CTS 07-11, September 2007, 12 p.)

Compilation of Pedestrian Safety Devices in Use at Grade Crossings
The Federal Railroad Administration has worked to gather information on any signs, signals, pavement markings, or other devices used to enhance the safety of pedestrians at grade crossings. State DOTs and rail transit operators have made several submissions, which have included background information and illustrations. These are presented here so that the larger grade crossing safety community might benefit from the work of others in this important area. (US Federal Railroad Administration report, January 2008, 32 p.)

Guidebook for Mitigating Fixed-Route Bus-and-Pedestrian Collisions
This report will be of interest to public transportation systems that provide fixed-route bus services and their communities. This Guidebook will assist small, medium, and large transit agencies and their community members in better understanding bus-and-pedestrian collisions and in determining preventative or remedial strategies for reducing the frequency and severity of these types of collisions. (Transportation Research Board TCRP Report 125, 2008, 75 p.)

Speed Management, A Road Safety Manual for Decision-Makers and Practitioners
This manual advocates a strong and strategic approach to creating a safe road system, with speed management at its heart. Reducing motor vehicle speeds in areas where the road user mix includes a high volume of vulnerable road users such as pedestrians and cyclists is especially important. This manual provides advice and guidance for policy-makers and road safety practitioners in low and middle-income countries and draws on the experience of a number of countries that have already initiated speed management programmes. Lessons from successful and non-successful initiatives are used to illustrate the advice provided. (Global Road Safety Partnership (GRSP) report, 2008, 196 p.)

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Pavements

Warm Mix Asphalt: European Practice
Warm-mix asphalt (WMA) is a group of technologies that allow a reduction in the temperatures at which asphalt mixes are produced and placed. These technologies tend to reduce the viscosity of the asphalt and provide for the complete coating of aggregates at lower temperatures. In 2007, a team of U.S. materials experts visited Belgium, France, Germany, and Norway to evaluate various WMA technologies through the Federal Highway Administration's International Technology Scanning Program. (US Federal Highway Administration Office of International Programs Report FHWA-PL-08-007, February 2008, 72 p.)

Prediction of Pavement Remaining Life
The objectives of the project were twofold. The first objective was to develop criteria for defining the end-of-life condition of pavements. These criteria could be applied in pavement deterioration modelling and mechanistic pavement design to obtain a more robust measure of the remaining life of pavements. The second objective was to generate a new model for maintenance costs. (Land Transport New Zealand Research Report 341, February 2008, 54 p.)

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Environment

Tracking Environmental Mitigation Projects: A Survey of Methods Used by State DOTs
To minimize the effects of road construction and development, WisDOT works to reduce change to the natural environment and leads several efforts to restore project areas. The Division of Transportation System Development (DTSD) is interested in learning whether other states have asset management systems or processes in place for tracking their environmental mitigation projects. DTSD is particularly interested in learning how other states track internal staff costs to design and monitor the mitigation facilities (wetland enhancements, wildlife crossings, detention basins for storm water runoff, etc.), construction costs to build the mitigation facilities, and costs to maintain the facilities over time (staff and materials). (Wisconsin Department of Transportation Transportation Synthesis Report, 28 February 2008, 6 p.)

Roads and Connectivity in Colorado: Animal-Vehicle Collisions, Wildlife Mitigation Structures, and Lynx-Roadway Interactions
This report investigates the impact of highways and landscape connectivity in Colorado. To do so, it describes three complementary research questions. Given the threat of roads to both wildlife populations and human safety, describing the distribution of animal-vehicle collisions (AVC) is a necessary step in understanding potential roadway impacts. The study results should be used for determining future locations of underpasses and other road-related mitigation for wildlife species, and future developments should continue to minimize impacts to rare and imperiled species. (Colorado Department of Transportation Report CDOT-2008-4, March 2008, 187 p.)

Environmental Effects of Emulsions
The great majority of bitumen emulsions used for chipsealing in New Zealand are cationic, i.e. the emulsifier provides the bitumen particles in the emulsion with a positive electrical charge. Continually increasing the use of these emulsions for chipsealing raises the question of the ecological risks and benefits of using these materials, as against the still more common method of using hot cutbacks, which are now classified by Environmental Risk Management Authority (ERMA) New Zealand as not ecotoxic (i.e. not toxic to the receiving environment). (Land Transport New Zealand Research Report 343, 2008, 47 p.)

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Traffic Control

Variable Speed Limit Signs Effects on Speed and Speed Variation in Work Zones
Technological advances allow speed limits to be changed in real time based on actual roadway conditions. There may be potential advantages to using variable speed limits in Utah, such as for traffic control during construction where the speed limit may be lowered adjacent to actual construction activities versus at other times or locations within an established work zone. This research will test the compliance and derive potential advantages from the use of variable speed limit equipment. (Utah Department of Transportation report UT-08-01, January 2008, 50 p.)

Towards credible speed limits
SWOV has elaborated the concept of 'credible speed limits' in a number of studies. A speed limit is credible if it meets the expectations that are aroused by the road and the road environment. For 80 km/hour roads SWOV carried out a photograph study, followed by an experiment in a driving simulator.The photograph study was used to determine which characteristics of the road and surroundings influence the credibility the most; in the driving simulator experiment we studied whether the driving behaviour was indeed influenced by these characteristics. The results showed that it is possible to choose a speed limit that is more credible for everybody; improving the credibility of the speed limit can be achieved by either adapting the speed limit itself or the road layout. (SWOV Institute for Road Safety Research Fact Sheet, November 2007, 5 p.)

Evaluation of the Flashing Yellow Arrow Permissive-Only Left-Turn Indication Field Implementation
The primary objective of this research was to evaluate the safety of the flashing yellow arrow (FYA) permissive only left-turn indication field installations. The ability of the FYA indication to improve safety was evaluated with respect to crash experience. Findings of the crash analysis were interpreted with respect to other variables such as signal phasing, vehicle flow rates, posted speed limits, and intersection geometry. The scope of this research included all known installations of the FYA prior to the commencement of this research. Data were limited to that which was made available by traffic engineers in locations where the FYA has been implemented, along with selected data that were directly obtained by the researchers. (TRB National Cooperative Highway Research Program web-only report 123, 2007, 146 p.)

Evaluation of Truck Lane Restriction on Non-limited Access Urban Arterials
The objective of this study was to evaluate the influence of various geometric, traffic, and signalization factors that might affect the effectiveness of truck lane restrictions on non-limited access highways, primarily urban arterial roadways with a significant amount of truck traffic. (Florida Department of Transportation Report - Project BD 543 RPWO 10, November 2007, 162 p.)

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