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 was a joint effort of the U.S. DOT ITS Joint Program Office and the FHWA Road Weather Management Program. It was 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 System was designed to enable various public agencies to more accurately assess weather and pavement conditions as well as their 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 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. Beginning in 2007, the U.S. DOT conducted 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 created Concepts of Operations tailored to their needs and provided their ESS data to the Clarus System. Phase 2 of the demonstration was 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 were implemented by private sector vendors and evaluated by the ITS Joint Program Office. Participation in Clarus grew since its early phase, with 37 states, 5 local agencies and 4 Canadian provinces connected and contributing data into the system when it ended. By June 2013, the goals and objectives of the Clarus Initiative were achieved, and the initiative ended.

The Road Weather Management Program also sponsored preliminary mobile sensing research. Noblis 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) also conducted a feasibility study to explore and assess the utility of using data from vehicles to improve surface transportation weather observations/predictions and road condition hazard analyses/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. Results are summarized in a a report titled Weather Applications and Products Enabled through VII: Feasibility and Concept Development Study. Research in this area continues with the Vehicle Data Translator (VDT) project whose goal is to ingest, process, and generate derived weather and road condition products for road segments.

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. In this project, FHWA work with 3 State agencies that evaluated and implemented the recommendations from the guidelines in installing or upgrading their Environmental Sensor Stations. The results of this study can be found in the report Implementation and Evaluation of RWIS ESS Siting Guide (PDF 1.4MB). These results were used to refine the guidelines as reflected in the document Road Weather Information System Environmental Sensor Station Siting Guide Version 2.0 (PDF 1.2MB). As transportation agencies continue to invest in RWIS sensing technologies by installing new stations or adding sensors to existing stations, the guidelines should serve as 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 6.0 of the MDSS software is now available from the National Center for Atmospheric Research MDSS Web site.

In 2004, MDSS technologies were mature enough for private sector companies to incorporate MDSS capabilities into their product lines for State DOT clients. In 2007, 21 state transportation agencies were using or developing MDSS tools. Sixteen 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 were in the process of procuring the software or have contracted with private vendors for maintenance decision support capabilities. In 2007, the FHWA began conducting benefit/cost analyses of operational MDSS applications being used by the pooled fund states and the Maine DOT (A Case Study of the Maintenance Decision Support System (MDSS) in Maine (HTML, PDF 540KB)), 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. A similar study was completed in 2010 for 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. FHWA released the Maintenance Decision Support System (MDSS) Deployment Guide (PDF 1.29MB) to assist agencies in adopting and implementing the system.

The FHWA offers free MDSS RoadShows and MDSS Showcases for state agency managers and field personnel. In the last couple of years, the FHWA Resource Center held MDSS Showcases in several locations. 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.

Based on the success of the MDSS prototype and related products, the program initiated efforts 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. Decision support output could include route-specific weather forecasts and recommendations for operations ranging from mowing and striping to the application of herbicides. The FHWA National Highway Institute (NHI) has also introduced a new online version of its Principles and Practices for Enhanced Maintenance Management Systems course to help agencies enhance routine highway maintenance and operations.

Weather-Sensitive Traffic Analysis and Prediction Models

In 2006, the Road Weather Management Program completed a research on Empirical Studies on Traffic Flow in Inclement Weather (HTML, PDF 1.8MB) that analyzed traffic and weather data and developed empirical models to 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. The models and results are designed to integrate weather and highway condition data in macroscopic traffic flow analysis and 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.

In 2007, the program initiated a study on microscopic analysis of traffic flow in inclement weather. This project focuses 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 results will be a methodology for identifying and modeling microscopic traffic parameters that are influenced by poor road weather conditions, as well as recommended procedures for incorporating these models into existing traffic analysis tools.

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.

Human Factors Analysis of Road Weather Advisory and Control Information

In 2008, the program initiated a study on Human Factors Analysis of Road Weather Advisory and Control Information. The objectives of this study are to identify traveler requirements for weather information (both pre-trip and en-route) and determine the most effective messages and methods for communicating road weather information. Specifically, this project will: (1) Identify the weather information requirements of travelers across a representative number of travel scenarios, (2) Evaluate the current state of the practice in weather-responsive traffic advisory and control strategies in terms of meeting those information requirements, and (3) Recommend ways to improve those practices including the development of communication and messaging standards. One of the major products from this study is a Guide for Designing Road Weather Information Messages and Dissemination Methods.

Integrating Weather into Traffic Management Center Operations

The Road Weather Management Program completed a research study in 2005 to analyze how weather and emergency information was currently being used in Traffic Management Centers (TMC) throughout the country. The research documented the state of the practice in weather integration and identified advanced practices. The study concluded 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). Recommendations from the study 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 guide, Integration of Weather Information in Transportation Management Center Operations: Self-Evaluation and Planning Guide (PDF 814 KB) was completed in 2008, and consists of the manual document and electronic self-evaluation that can be downloaded from the FHWA Web site. As part of the guide development FHWA worked with two TMCs to conduct a self-evaluation using the guide and develop a weather integration plan. The guide is currently being promoted and deployed around the country, with FHWA now working with at least 4 TMC's in conducting the self-evaluation and developing weather integration plans.

The following is a listing of resources relating to Integrating Weather into Traffic Management Center Operations:

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).

External Programs Related to Road Weather Management

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