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MDSS Challenges, MDSS Challenges, Research & Research & Managing Managing

ExpectationsExpectations- Road Conditions -- Road Conditions -

Prof. Leon OsborneProf. Leon Osborne

Surface Transportation Surface Transportation Weather Research CenterWeather Research Center

University of North DakotaUniversity of North Dakota

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Goal of MDSS . . .Goal of MDSS . . .

• To achieve desired levels of accuracy of road condition predictions at all locations of interest to the winter maintenance community

• To convey the appropriate treatment recommendations to decision makers to permit a desired level of service

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Factors Determining Road Factors Determining Road Conditions . . .Conditions . . .

• ‘‘Weather’ Weather’ – The most crucial factor forcing particular road conditionsThe most crucial factor forcing particular road conditions

• ‘‘Land-Use, Soils & Road Structure’ Land-Use, Soils & Road Structure’ – Sets the background characteristics that influence how Sets the background characteristics that influence how

pavements respond to weather elementspavements respond to weather elements

• ‘‘Treatment Strategies’ Treatment Strategies’ – Materials and timing of treatments alter the weather-Materials and timing of treatments alter the weather-

influenced road conditionsinfluenced road conditions

• ‘‘Traffic’ Traffic’ – Can (often) alters ice/snow/water distribution on pavementCan (often) alters ice/snow/water distribution on pavement

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Pavement

LOSSESLOSSESLOSSESLOSSES

WeatherWeatherWeatherWeather

ChemicalChemicalChemicalChemicalTrafficTrafficTrafficTraffic

WeatherWeatherWeatherWeather RunoffRunoffRunoffRunoff

Sub-sfcSub-sfcSub-sfcSub-sfc

Sub-sfcSub-sfcSub-sfcSub-sfc

PlowingPlowingPlowingPlowing

TrafficTrafficTrafficTraffic

WeatherWeatherWeatherWeatherChemicalChemicalChemicalChemical

TrafficTrafficTrafficTraffic

Sub-sfcSub-sfcSub-sfcSub-sfc

WeatherWeatherWeatherWeather RunoffRunoffRunoffRunoff

Sub-sfcSub-sfcSub-sfcSub-sfc

PlowingPlowingPlowingPlowing

Past Future

TrafficTrafficTrafficTraffic

GAINSGAINSGAINSGAINS

Mass Energy

contaminant layer

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Road Condition Prediction ProcessRoad Condition Prediction Process

• Predictions are made by Predictions are made by achieving a balance achieving a balance between mass and between mass and energy forcing on the energy forcing on the pavement.pavement.

• Results in a forecast of:Results in a forecast of:– Pavement temperaturePavement temperature– Mass (ice, snow, water) on Mass (ice, snow, water) on

the pavement the pavement

Energy

Mass Mass

Energy

Before After

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Achieving True Balance Is DifficultAchieving True Balance Is Difficult

• Results from a lack Results from a lack of complete of complete description of all description of all physical processesphysical processes

• Gives errors in Gives errors in pavement pavement temperaturestemperatures– Greater the Greater the

imbalance, the larger imbalance, the larger the errors the errors

Energy

MassMass

Energy

Before After

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SNTHERM_RT Simulation (Adam Mohr - UND)

Weather Example: Cloud Cover Weather Example: Cloud Cover ImpactsImpacts

CloudCover

CloudCover

Pavement TemperatureImpact

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Treatment Example: Treatment Example: The ‘Ice Cream Freezer’ The ‘Ice Cream Freezer’

EffectEffect

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Balance . . . But At A Price!Balance . . . But At A Price!

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Road / Roadway CharacterizationRoad / Roadway Characterization

• Crucial to the success of a road condition prediction Crucial to the success of a road condition prediction model model (Yet information is often difficult to obtain)(Yet information is often difficult to obtain)

Vegetation (including sky view)

snow cover

terrain

sub-grade

pavement materials/layers

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Issues / Limitations Requiring Issues / Limitations Requiring Further Research . . .Further Research . . .

• Weather forecast qualityWeather forecast quality– Particularly precipitation and radiation (cloud cover) forecastsParticularly precipitation and radiation (cloud cover) forecasts

• Quality of observations from ESS sitesQuality of observations from ESS sites

• Accurately quantifying roadway and bridge propertiesAccurately quantifying roadway and bridge properties

• Understanding / modeling the effect of trafficUnderstanding / modeling the effect of traffic

• Understanding /modeling of chemical diffusion and Understanding /modeling of chemical diffusion and loss propertiesloss properties

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Issues / Limitations Requiring Issues / Limitations Requiring Further Research . . . (continued)Further Research . . . (continued)

• Understanding the combined affects of multiple Understanding the combined affects of multiple chemicalschemicals

• Quantifying what is an acceptable road conditionQuantifying what is an acceptable road condition

• Understanding / modeling the processes Understanding / modeling the processes associated with falling / blowing snow relative to associated with falling / blowing snow relative to the road surfacethe road surface

• Lack of accurate (real-time) information on Lack of accurate (real-time) information on maintenance actions performed maintenance actions performed

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Simulation of Mass Distribution Due Simulation of Mass Distribution Due to Trafficto Traffic

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Management of Treatment Action Management of Treatment Action DataData

Recommendation

Action

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SummarySummary• Significant progress has been made in Significant progress has been made in

understanding the scope of the issues understanding the scope of the issues outstanding in road condition monitoring and outstanding in road condition monitoring and predictionprediction

• More research is needed to advance the More research is needed to advance the methodologies and reduce the uncertainty of methodologies and reduce the uncertainty of operational road condition predictions operational road condition predictions (although (although there will always be uncertainty)there will always be uncertainty)

• The advancements will depend upon cooperation The advancements will depend upon cooperation between the maintenance and weather between the maintenance and weather communitiescommunities

• Expectations need to be sized to the capabilitiesExpectations need to be sized to the capabilities