Baselining Current Road Weather Information

The Federal Highway Administration (FHWA) Road Weather Management Program (RWMP) recently completed a study to establish a baseline for current road weather information by characterizing the sources and evaluating the quality attributes of road weather parameters used by transportation agencies. Baselining serves as a reference for future comparisons of enhanced road weather information enabled by Clarus and other advanced road weather management technologies. By characterizing existing weather information, the results may be used by all surface transportation weather interests as a benchmark for measuring improvements over time.

Varying levels of quality characterize existing sources of road weather information, and often times paint an incomplete or inaccurate picture of conditions on or near the road surface. These deficiencies were well documented in the 2004 National Research Council report Where the Weather Meets the Road: A Research Agenda for Improving Road Weather Services. To overcome the deficiencies identified in the report and to improve road weather information products, the U.S. DOT is investing in Intelligent Transportation Systems (ITS). One such ITS initiative is Clarus. The goal of Clarus is to develop and demonstrate an integrated surface transportation weather observing, forecasting, and data management system. Clarus is designed to enable public and private information providers to produce anytime, anywhere road weather information to meet the needs of all road users and operators. Such outputs will ultimately help improve mobility and safety by alleviating the impacts of adverse weather on the surface transportation system.

The recent baselining project focused on the content and usefulness of road weather information as evaluated by transportation agencies presently using road weather information in their routine activities to use advisory, control, and treatment road weather management strategies. The characterization used attributes deemed important to the users of road weather information and directly applicable to weather information and associated products. The six quality attributes were:

• Accuracy/Precision - “Closeness” between an observed or forecasted condition and the actual condition;

• Completeness - Adequate information to fulfill users' requirements;

• Relevance - Fit of the information to the users' needs;

• Currency/Latency - Age of the information;

• Timeliness/Reliability - Consistent and on-time delivery of information; and,

• Ease of Use – Facility to get, interpret, and use the information.

A broad spectrum of 16 Product Types and 45 Road Weather Elements was characterized. Product Types described a packaged collection of road weather information, while Road Weather Elements included individual pieces of information that are either contained in a product type or reported individually. Each information element evaluated was presently being used, and is expected to remain active, for surface transportation decision-making. A national survey of transportation agencies was conducted to determine the perceived quality of each information element relative to the six quality attributes.

Although the present quality levels are considered by users to be of reasonably high quality, there exists room for improvement. The quality assessment identified certain Road Weather Elements such as pavement temperature, road closure, severe weather watches and warnings, and advisory messages to be presently of high quality, while other road weather information such as cloud cover and pavement chemical concentration are of lesser quality.

The study concluded that benefit from the baselining effort would be best achieved through ongoing monitoring at intervals showing changes because of the timing of influences on the evolution of road weather activities. This interval is roughly every 2 years.

The anticipated outcomes of the ongoing monitoring are:

• Improved Road Weather Observations;

• Improved Traveler Advisory Content with Road Weather Information;

• Improved Winter Maintenance Tactical Response to Snow and Ice Conditions;

• Improved Responsiveness by Traffic Managers on Placing Weather-Related Traffic Controls;

• Higher Quality Road Weather Products Provided by the Road Weather Service Provider Community;

• Greater Confidence by Transportation Personnel in Road Weather Products and Services;

• Incentives for Improvement of Instrumentation or Processing to Address Elements Perceived as Low Quality Resources; and,

• Continuing System Improvement for Road Weather Information Products.

Developing confidence in road weather information requires assurances of quality information. How well this confidence is achieved will be found in the changes in road weather information quality characteristics. Ongoing monitoring will provide a road weather community “report card” and indicate needed improvements.

The presentation will provide additional details of the results achieved in the initial survey of the road weather community. It will also describe new efforts underway by the FHWA RWMP to extend the baseline development efforts through the construction and application of an electronic database of road weather information quality attributes.