Winter Performance Measures among 3 finalists
in national competition for 'Best New Innovative Practices'
ITD’s unique Winter Performance Measures, a process for evaluating winter storm maintenance is a national finalist in the Intelligent Transportation Society of America’s 2013 Best of ITS Awards.
Pioneered in District 5 and adopted statewide, the process uses winter storm indexing to determine the most appropriate and effective treatment of highways before and during a storm. Data collected from Idaho’s 100 Road Weather Information System sites helps maintenance workers determine which materials to apply to highways, how much to apply and when to apply.
Attention from abroad Highway maintenance officials throughout the country are evaluating ITD’s model approach for possible implementation. After the process was showcased at the annual WASHTO (Western Association of State Highway and Transportation Officials) meting in Colorado last summer, representatives from 14 states contacted ITD, including Kansas, Pennsylvania, Utah, Nevada, Wyoming, Maryland, Wisconsin, Minnesota, North Dakota and South Dakota. Several universities and research centers also expressed interest in the ITD process. The Weather Programs Ministry of the British Columbia Ministry of Transportation and Infrastructure (BCMTI) also requested more information: “We’re particularly interested in the methodology and the development of the algorithms that make it work … We have a well-developed RWIS (Road Weather Information System) network in BC, although our station density is considerably less than in Idaho, and we're looking at replacing all of our 'in-pavement' surface temperature and condition sensors with the same type of optical pavement sensors that are in use in Idaho …” (Simon Walker, BCMTI). The appeal will spread even further this summer, making debuts in Europe and Asia. Vaisala, a partner in data collection for ITD’s Winter Storm Indexing, has been requested to give presentations at Intelligent Transportation Society meetings in Ireland, Japan and Andorra. |
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ITD is one of three states being considered for the award in the Best New Innovative Practices category. Also in contention for the award are the Michigan Department of Transportation for its Southeast Michigan Transportation Operations Center and Virginia Department of Transportation for the Virginia ITS Communication Network – A Public-Private Partnership Success.
Each of the finalists will be recognized and the winners will be announced during the 23rd ITS America Annual Meeting and Exposition on Monday, April 22, in Nashville.
Winter Performance Measures/winter storm indexing is a revolutionary process that eliminates much of the subjective decisions involved in highway treatments, such as salt, brine and chemical de-icers and anti-icers. They also give ITD a common benchmark for evaluating the effectiveness of those measures after storms subside.
The application of highway treatments before and during storm events largely is based on data captured at 100 RWIS sites throughout the state. Using empirical data analysis, ITD’s winter storm index measures the severity of weather storms and the duration of ice and snow on highways to establish measures for maintenance practices.
The index is a measure of ice and snow duration per unit of storm severity. That severity is based on wind speed, snow accumulation and surface temperature. Ice duration is defined as the length of time “grip,” or traction, falls below 0.6. Data collected from the RWIS stations is used to determine parameters in the storm index formula. Storm index algorithms calculate:
1. Storm severity based on precipitation amounts, wind velocity and surface temperature
2. “Grip” recovery
3. Mobility index that shows how well wet pavements were maintained during sub-freezing conditions
Why are Winter Performance Measures important?
ITD expends approximately $30 million annually on winter maintenance, using 500 vehicles statewide. ITD needed a tool for measuring the effectiveness of winter maintenance operations to achieve the greatest efficiency for the financial investment.
Previously available performance measures did not provide the ability to easily determine when changes in winter maintenance operations resulted in improved safety and mobility outcomes.
Maintenance decisions were largely left to subjectivity and the experience of snow plow operators. The advent of new treatments – liquid anti-icers, de-icers and brine, used in combination with salt challenged operators to balance the distinct advantages of each method.
How effective are the new measures?
Winter slide-offs were reduced by more than 40 percent in southeast Idaho where storm indexing was pioneered. Ice duration has been reduced by about 75 percent. These reductions are possible because ITD has a quantified result from each storm crewmembers for use in defining best practices and improved outcomes.
Societal costs have been reduced significantly since each slide-off results in residual costs of about $1,000. Winter mobility is significantly increased because ice duration is reduced. Ultimately, use of the storm weather index helps ITD provide safer travel for motorists during challenging winter conditions, reduces delays in mobility, and improves commerce, each of which is key to the department’s mission and strategic plan.
Published 4-5-13