Road Weather Management Program
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Projects and Programs

FHWA Road Weather Management Program Projects and Activities

This section highlights some of the projects and activities of the FHWA Road Weather Management Program including:

Clarus Initiative

The Clarus Initiative is a joint effort of the U.S. DOT ITS Joint Program Office and the FHWA Road Weather Management Program. The Clarus Initiative is a multi-year effort to develop and demonstrate an integrated surface transportation weather observation data management system, and to establish a partnership to create a Nationwide Surface Transportation Weather Observing and Forecasting System. The Clarus Initiative Flyer (PDF 1.1MB) provides a brief summary of the goals and benefits of the initiative.

The Clarus Concept of Operations was completed in June 2005. Based upon this Concept of Operations, a proof-of-concept system was designed and demonstrated in 2006. The Clarus System is designed to enable various public agencies to more accurately assess weather and pavement conditions as well as the impacts on operations. Such knowledge is critical for planning, conducting, and evaluating the effectiveness of activities such as winter road maintenance, weather-responsive traffic management, traveler information dissemination, safety management, transit vehicle dispatching, and flood control.

The Clarus Initiative Coordinating Committee (ICC) is an interdisciplinary source of expertise and guidance for the initiative. At the most recent ICC meeting in September 2007, Clarus stakeholders learned about the progress of the Clarus Multi-state Regional Demonstrations. From 2007 to 2010, the U.S. DOT will conduct the Clarus Multi-state Regional Demonstration to prove that the Clarus System functions as designed by encouraging state and local agencies to contribute ESS data, enabling proactive transportation system management though use of Clarus System data, and providing an environment for private sector innovation. In Phase 1, teams of public transportation agencies are creating Concepts of Operations tailored to their needs and providing their ESS data to the Clarus System. Phase 2 of the demonstration is called the Connection Incentive Program. This program provides financial assistance to eligible U.S. public agencies to help offset costs for collecting metadata and connecting to the Clarus System. In Phase 3, the solutions described in the Phase 1 Concepts of Operations will be implemented by private sector vendors and evaluated by the ITS Joint Program Office.

The Road Weather Management Program has also sponsored preliminary mobile sensing research. Mitretek Systems performed foundational research on the characteristics and the feasibility of using vehicles as meteorological sensor platforms. Vehicles were equipped with air temperature sensors in the front bumper, near the engine air intake cowling, and in the rear bumper. The primary research areas included temperature bias vs. vehicle speed, mobile temperatures vs. in situ observations, importance of sensor placement, thermal characteristics of similar vehicles, and effects of external phenomena on mobile temperatures. More information on this research can be found in a presentation on Vehicles as Mobile Meteorological Platforms: Introductory VII Research (PPT 6.6MB). The National Center for Atmospheric Research (NCAR) conducted a feasibility study to explore and assess the utility of using data from vehicles to improve surface transportation weather observations and predictions and road condition hazard analyses and predictions. Researchers identified technical issues and challenges related to the use of vehicle data, and provided recommendations that will help ensure successful exploitation of vehicle probe data in weather applications. Study results are summarized in a presentation on The Feasibility of Using Vehicles as Probes (PPT 3.1MB) and in a report titled Weather Applications and Products Enabled through VII: Feasibility and Concept Development Study. As part of the Clarus Initiative, the FHWA has also sponsored foundational research to assess the feasibility of obtaining video imagery from State DOT Closed Circuit Television (CCTV) cameras to determine if new surface transportation-related elements can be derived. Researchers at the MIT Lincoln Laboratory have created an algorithm that uses visible camera imagery, with automated orientation, to estimate road-way visibility.

RWIS Environmental Sensor Station Siting Guidelines (HTML, PDF 2.4MB)

In order to enhance observation capabilities and define requirements for road weather observing systems, the Road Weather Management Program partnered with the Aurora Pooled Fund Program, and the AASHTO Snow and Ice Cooperative Program to developed siting guidelines for Environmental Sensor Stations (ESS) in the roadway environment. The Road Weather Information System (RWIS) ESS Siting Guidelines - released in April 2005 - provide a set of recommendations to support uniform siting of sensor stations that collect road and weather observations for RWIS.

In 2006, the Road Weather Management Program initiated a project to implement and evaluate the guidelines in a field environment to ensure that the recommendations are realistic and that the contents are credible, understandable, and useful to the deployers. During this project, the FHWA will work with state agencies that utilize the recommendations of the guidelines when installing or upgrading Environmental Sensor Stations. The results of this study will be used to refine the guidelines as necessary. As transportation agencies continue to invest in RWIS sensing technologies by installing new stations or adding sensors to existing stations, the refined guidelines will become a valuable tool to aid in their placement.

Maintenance Decision Support System (MDSS) Prototype

The Maintenance Decision Support System (MDSS) prototype is a decision support tool that integrates relevant road weather forecasts, coded maintenance rules of practice, and maintenance resource data to provide winter maintenance managers with recommended road treatment strategies. Based upon user requirements, a team of national laboratories developed the MDSS prototype in 2001. From 2002 to 2007, the prototype underwent five development cycles and three field demonstrations in Iowa and Colorado. Version 5.0 of the MDSS software is now available from the National Center for Atmospheric Research MDSS Web site.

By 2004, MDSS technologies were mature enough for private sector companies to incorporate MDSS capabilities into their product lines for State DOT clients. By 2007, 21 state transportation agencies were using or developing MDSS tools. Thirteen states have joined the MDSS Pooled Fund Study led by the South Dakota DOT to develop an enhanced version based on the federal MDSS prototype, while others are in the process of procuring the software or have contracted with private vendors for maintenance decision support capabilities. In 2007 and 2008, the FHWA will conduct evaluations of operational MDSS applications being used by the pooled fund states, the Maine DOT, and the City and County of Denver, Colorado.

Current and upcoming efforts associated with the FHWA MDSS effort include: (1) promoting deployment of the MDSS for winter road maintenance, and (2) expanding the scope of MDSS to become a Maintenance and Operations Decision Support System (MODSS) that supports other weather-related decision making, such as for summer maintenance and construction.

The FHWA offers free MDSS RoadShows for state agency managers and field personnel. The AASHTO Technology Implementation Group has selected the MDSS as a "Focus Technology". The Technology Implementation Group identifies and champions the deployment of "ready-to-use" technologies that are likely to yield significant benefits to users. AASHTO members are developing educational brochures and videos for distribution to the winter maintenance community.

Fourteen states have joined the MDSS Pooled Fund Study led by the South Dakota DOT to develop an enhanced version based on the federal MDSS prototype, while others are in the process of procuring the software or have contracted with private vendors for maintenance decision support capabilities. In 2007, the FHWA will conduct benefit/cost analyses of operational MDSS applications being used by the pooled fund states, and the Maine DOT to document the extent to which costs and benefits vary depending upon local operational characteristics. The objectives of the benefit/cost analyses are to quantify costs for winter maintenance operations, estimate benefits of deploying MDSS in state agencies, estimate the costs of deploying MDSS, and calculate benefit-to-cost ratios for MDSS deployments.

Based upon the success of the MDSS prototype, the program has initiated the MODSS effort to foster decision support tools for other road maintenance and operations personnel. In 2007, the program held meetings with summer maintenance stakeholders and traffic management stakeholders to refine user needs and gather information needed to develop decision support systems tailored for their operations. MODSS output will include route-specific weather forecasts and recommendations for operations ranging from mowing and striping to the application of herbicides. An initial prototype of MODSS is expected to be made available for evaluation during the last quarter of 2008.

  • MDSS Roadshow - FHWA is offering free seminars to those involved with winter road operations. Come see how Maintenance Decision Support System (MDSS) technology is transforming the world of winter maintenance.

Incorporating Weather Impacts into Traffic Analysis Tools

The Road Weather Management Program recently completed Empirical Studies on Traffic Flow in Inclement Weather (HTML, PDF 1.8MB) that analyzed traffic and weather data and developed empirical models that quantify the impacts of weather on traffic flow.  Data from three cities—Seattle, WA; Minneapolis, MN; and Baltimore, MD—were used to develop statistical models and adjustment factors for traffic capacity, speed and density as functions of precipitation intensities and visibility levels. Study results will be used to foster the incorporation of weather and pavement condition data into existing traffic engineering models and to support the development of weather-responsive traffic management strategies. The study also proposed data collection and analysis procedures for microscopic responses or driver behavior inclement weather.

Knowing which critical parameters within a driving behavior model should be changed under various weather conditions will aid in the development of weather-responsive traffic management strategies. In 2007, the program initiated a project to conduct a microscopic analysis of traffic flow in inclement weather. This project will focus on how weather events and associated road conditions affect driver behavior including lane changing, car-following, gap acceptance, turning movements, as well as acceleration and deceleration on freeways and arterial roads. The study will examine the variations in responses to weather events by driver and traffic characteristics, type of highway/facility, time of day, trip purpose, familiarity with the area/conditions, environment and other relevant parameters. The results will be a methodology for identifying and modeling microscopic traffic parameters that are influenced by poor road weather conditions and recommended procedures for incorporating findings into existing traffic microsimulation models.

There is considerable body of literature and knowledge related to how weather events affect traffic flow and traffic operations. One of the challenges for the transportation community is to incorporate this knowledge into traffic management strategies or decision support systems to help improve the performance of the transportation system during inclement weather conditions. Traffic Estimation and Prediction Systems (or TrEPS) are some of the tools currently available for traffic managers and operators to assist with evaluating and implementing weather-responsive traffic management strategies. TrEPS predict where and when drivers travel on the road network, and enable dynamic control and traffic management systems to anticipate problems before they occur, rather than simply reacting to existing conditions. Significant improvements in traffic estimation/prediction capabilities and overall utilities of these systems for traffic control and management can be achieved by upgrading or adjusting them to account for the impacts of weather. In 2007, the RWMP began a project to develop weather-sensitive traffic prediction and estimation models, and incorporate them into existing TrEPS.

Integrating Weather into Traffic Management Center Operations

The Road Weather Management Program, in partnership with the Emergency Transportation Operations Program, sponsored a research project to study how weather and emergency information is being integrated into operations at 38 Traffic Management Centers. The project team described the state of the practice in weather integration and identified integration best practices. They found that successful integration of weather information allowed improve capability and preparation for incident management by Traffic Management Center (TMC) staff and dissemination of traveler information. More information can be found in the final report Integration of Emergency and Weather Elements into Transportation Management Centers (HTML, PDF 1.7MB) and Weather Integration in Transportation Management Centers. Recommendations in the final report include building awareness and creating a culture within TMCs that acknowledges the value of weather information and makes integration a standard business practice, improving communications among the users of weather information in the TMCs and the field, developing guidelines and conducting self-assessment programs, and developing new concepts and tools to help facilitate the weather integration process.

In general, very limited integration and application of weather information for TMC operations were observed. In some cases where good examples of weather integration were found, the approaches taken by the agency were specific to the needs of the region or state. Clearly there is a need to advance the state of the practice and help agencies overcome the challenges associated with weather integration in TMCs. To address these challenges, the Road Weather Management Program initiated a project to develop a self-assessment guide to help TMCs evaluate their weather information integration needs and assist them in creating a plan to meet those needs. The FHWA will work with at least two TMCs to conduct a self-assessment using the guide and developing a weather integration plan.

Weather Response System Prototype (HTML, PDF 2.4MB)

The FHWA Road Weather Management Program partnered with the Missouri DOT to deploy and evaluate a Weather Response System (WRS) to support weather-responsive transportation operations. The prototype system displays national, state, and local maps from the NOAA National Digital Forecast Database (NDFD) and allows selection of NWS Doppler radar images from radar stations across the nation. The system allows users to select desired conditions and determine when such conditions are predicted for a specified area. The prototype system was evaluated in the Kansas City Traffic Management Center (TMC) in 2006. Missouri DOT staff found it to be useful in scheduling their activities and managing traffic operations before and during adverse weather. More information can be found in the project report Weather Response System: Operational Observations Report (HTML, PDF 2.4MB).

Road Weather Resource Identifier

Over the years, the FHWA Road Weather Management Program has gathered hundreds of road weather resources including research reports, articles and other publications. This tool, which contains a database of over 600 resources, has been developed to help transportation professionals find road weather documents that suit their specific needs. The tool enables users to navigate database resources using a guided search, a menu of topics search or a keyword search. In 2005, the prototype version of the Road Weather Resource Identifier was downloaded and evaluated by several state DOTs, local transportation agencies, as well as private, federal, academic, and international agencies. Testing and evaluation of this version was completed in the spring of 2006, and an enhanced version was released in late 2006.

Principles and Tools for Road Weather Management Course

External Programs Related to Road Weather Management

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