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U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Public Roads - July/August 2016

Date:
July/August 2016
Issue No:
Vol. 80 No. 1
Publication Number:
FHWA-HRT-16-005
Table of Contents

Communication Product Updates

Communication Product Updates

by Lisa A. Shuler of FHWA's Office of Corporate Research, Technology, and Innovation Management

Below are brief descriptions of communications products recently developed by the Federal Highway Administration’s (FHWA) Office of Research, Development, and Technology. All of the reports are or will soon be available from the National Technical Information Service (NTIS). In some cases, limited copies of the communications products are available from FHWA’s Research and Technology (R&T) Product Distribution Center (PDC).

When ordering from NTIS, include the NTIS publication number (PB number) and the publication title. You also may visit the NTIS Web site at www.ntis.gov to order publications online. Call NTIS for current prices. For customers outside the United States, Canada, and Mexico, the cost is usually double the listed price. Address requests to:

National Technical Information Service
5301 Shawnee Road
Alexandria, VA 22312
Telephone: 703–605–6000
Toll-free number: 1–888–584–8332
Web site: www.ntis.gov
Email: customerservice@ntis.gov

Requests for items available from the R&T Product Distribution Center should be addressed to:

R&T Product Distribution Center
Szanca Solutions/FHWA PDC
700 North 3rd Avenue
Altoona, PA 16601
Telephone: 814–239–1160
Fax: 814–239–2156
Email: report.center@dot.gov

For more information on R&T communications products available from FHWA, visit FHWA’s Web site at www.fhwa.dot.gov, the FHWA Research Library at www.fhwa.dot.gov/research/library (or email fhwalibrary@dot.gov), or the National Transportation Library at ntl.bts.gov (or email library@dot.gov).

 

The Use of Data in Planning for Operations: State-of-the-Practice Review (Report)

Publication Number: FHWA-HRT-15-071

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Planning for operations provides the foundation for proactively operating a transportation system. FHWA promotes the use of a performance-based approach for the integration of operations into the transportation planning and investment decisionmaking processes at metropolitan and State levels.  Access to comprehensive, high-quality data on the operation of the transportation system is vital to applying this approach fully.

This report reviews the state of the practice among metropolitan planning organizations in using data to support planning for operations activities. Planners and operators can use this report to generate ideas to advance their efforts to use data to plan for operations.

In 2012, FHWA initiated a 3-year project, Virtual Data Access (VDA) Framework, to develop a prototype for sharing planning and operations data between State and local transportation agencies from multiple sources within a region.  The framework will bring together many types of transportation data to give planners and operators a multifaceted view of transportation performance, both over time and by location.  The purpose of the VDA Framework is to improve the breadth of available data and reduce the barriers to use of that data.  Through greater access to data collected in a region, metropolitan planning organizations and State transportation departments will be better equipped to conduct performance management and performance-based planning and programming, as emphasized in the Moving Ahead for Progress in the 21st Century Act.

FHWA’s project focused on using the VDA Framework to support planning for operations, including the use of data from the framework as input to planning for operations analysis and simulation tools. FHWA developed a pilot implementation of the framework with transportation partners in the Kansas City, MO, region who will use the data to support reporting operational performance measures.

This document is available at www.fhwa.dot.gov/publications/research/operations/15071/index.cfm.

 

Safety Evaluation of Wet-Reflective Pavement Markings (TechBrief)

Publication Number: FHWA-HRT-15-083

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FHWA researchers upgraded existing markings from standard marking materials to wet-reflective markings to examine the safety impacts on roadways in Minnesota, North Carolina, and Wisconsin.  The wet-reflective markings may be applied as a paint, tape, or thermoplastic material, and they are designed to provide an improved level of retroreflectivity during wet road surface conditions.  This report describes the study.

In Minnesota, researchers applied the markings on two-lane roadways and freeways on the center line, edge line, or lane lines. In North Carolina, they applied the markings on the edge line or lane lines on freeways. In Wisconsin, they applied them for the lane lines on freeways and multilane divided roadways.

The purpose of the study was to estimate the safety effectiveness of this strategy as measured by crash frequency.  The study did not include crashes occurring at or related to intersections and snow/slush/ice- and animal-related crashes.  The researchers considered target crash types, including total crashes; injury crashes of differing severities, run-off-road crashes, sideswipe-same-direction crashes, wet-weather crashes, nighttime crashes, and nighttime wet-weather crashes.  The effects for dry-road crashes were inferred from the effects for total and wet-road crashes.

The researchers also conducted a disaggregate analysis to investigate whether the safety effects vary by factors such as the level of traffic volume, the frequency of crashes before treatment, roadway type, posted speed limit, lane width, and shoulder width. Evaluation of overall effectiveness included a consideration of installation costs and crash savings in terms of the benefit/cost ratio.  The researchers used the empirical Bayes methodology for observational before-after studies.

Benefit/cost ratios estimated with conservative cost and service life assumptions are 1.45 for freeways and 5.44 for multilane roads. With the sensitivity analysis recommended by USDOT, these values could range from 0.83 to 2.04 for freeways and 3.10 to 7.67 for multilane roads.  The results suggest that the wet-reflective markings treatment--even with conservative assumptions on cost, service life, and the value of a statistical life--can be cost effective, especially for multilane roads.

This document is available to download at www.fhwa.dot.gov/publications/research/safety/15083/index.cfm.

 

Agent-Based Modeling and Simulation In the Dilemma Zone (Report)

Publication Number: FHWA-HRT-15-082

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Gaining a comprehensive understanding of drivers’ decisions and behaviors in dilemma zone situations can help State, county, and city transportation agencies develop and deploy effective countermeasures to improve safety and reduce potential crashes at signalized intersections.  The dilemma zone is an area in and around an intersection in which a driver cannot stop gently before the stop line or clear the intersection safely before the red phase.  This report discusses research aimed at developing a dilemma zone behavior model that considers how certain factors found at signalized intersections--such as a pedestrian countdown signal, a red-light photo enforcement camera, and the behavior of an adjacent vehicle--affect drivers.

Researchers used FHWA’s Highway Driving Simulator to collect various data. Factors examined in assessing the influence of the road environment on driver decisionmaking behavior within the dilemma zone simulation included the roadway’s speed limit, presence of a red light photo enforcement camera or pedestrian countdown signal at the intersection, and others.

Researchers developed a dilemma zone behavior model based on data collected in the driving simulation experiments via agent-based modeling and simulation.  The research framework represents uncertain perception and decision behaviors of humans in a probabilistic manner.  To demonstrate and validate the proposed approach, researchers compared the drivers’ actions under two circumstances. Under the first, drivers only knew the approach speed and distance to the stop (that is, internal information). Under the second circumstance, drivers knew the internal information as well as external information, such as presence of a pedestrian countdown signal or a red-light photo enforcement camera, and the behavior of an adjacent vehicle.

Experiment results suggest that sufficient external information, such as the presence of a camera, can accurately predict the decisions of drivers when they are confronted with the dilemma zone.  The dilemma zone behavior model also takes into account the interactions between vehicles and provides realistic predictions of driver behaviors under various traffic conditions.

This document is available to download at www.fhwa.dot.gov/advancedresearch/pubs/15082/index.cfm.