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There are many tools available to maintenance personnel to help train, manage, and provide direction for winter operations. Below is a list of the current tools that are currently available.
Statewide Maintenance Forecast/Weatherdesk
Statewide Maintenance Forecast/Weatherdesk
The UDOT Weather Operations group contracts a private weather service to provide road weather forecasting and support for UDOT and its maintenance staff. These text-based forecasts are tailored to road and travel impacts and should help guide your decision-making.
Elements of the forecast in the winter include timing and amounts of road snow, temperature and wind information, as well as precipitation type, road temperatures, and snowfall intensity.
In the summer, extreme heat, fire danger, and flooding concerns are noted.
These forecasts are issued via email and on the statewide maintenance forecast website (udottraffic.utah.gov/forecastview) at 2:00 A.M. and 2:00 P.M. daily between November 1st and April 30th and only at 2:00 P.M. between May 1st and October 31st. The weather desk can also be contacted 24/7/365 at 801-887-3703 if you have any questions or want updates to the forecast. A meteorologist with the private weather service may also call the shed supervisor to alert them of changing weather conditions and/or potentially significant impacts coming.
To sign up to receive the forecast, visit the statewide maintenance forecast website (udottraffic.utah.gov/forecastview), then click on the “Subscribe to Forecasts and RWIS Alerts” link in the “Contact” box in the top left corner. Then click on the “create an account” link on the bottom right. Fill out your contact information and you should then receive an email after a member of the Weather Operations group has created your account.
Automatic Vehicle Locator (AVL)
Automatic Vehicle Locator (AVL)
UDOT outfits each snow plow and other vital equipment used in winter operations with a GPS locator. The GPS locator provides real time data that can be used to assist maintenance personnel in performing the most efficient winter operations possible. The data can also be used to identify areas or situations where performance can be improved with a different approach or the use of other equipment. The AVL system provides mechanics with equipment diagnostic codes allowing mechanics to diagnose equipment problems without being on site enabling them to bring necessary parts for repair work, saving time and effort.
The AVL system operates year round and toggles between 30 second and 120 second “location pings” depending on the time of year. For wintertime operations the AVL begins October 31st of each year and runs until April 30th. During this time period the AVL system actively locates each outfitted vehicle every 30 seconds. From May 1st to October 31st the AVL system actively locates each outfitted vehicle every 120 seconds. The AVL locating provides UDOT maintenance personnel with the following data at the present time:
Location of the vehicle
Speed at which the vehicle is currently traveling
Max speed of the vehicle during current trip
Provides a path of where the vehicle has been (“breadcrumb trail”)
Equipment diagnostic codes for vehicle troubleshooting
Recalls from manufacturer
Status of the snow plow
Active
Stationary
Parked (ignition off)
Broken
Coaching of drivers (speeding, hard stops, aggressive driving, etc.)
The AVL software currently in use is the Verizon Reveal and is managed by the senior business analyst for the UDOT equipment group. They can provide a login and password to access the site.
The AVL software allows personnel a variety of functions that can be tailored to the needs of the individual maintenance station or expanded to cover larger areas. Reports can be created and other functionality provided. Within the software there is a “Training Center” that provides video instructions and booklets that can be downloaded to provide assistance. For additional assistance with the software please contact the winter operations engineer in Central Maintenance.
The UDOT Traffic App is a smart phone app available to Iphone and Android users. Once the UDOT Traffic App is installed on a smartphone, the user can select an option to view snow plows on an active map along with Weathernet forecasts. All snow plows that are currently active are displayed on the map (November 1st through April 30th). The app also shows the path (breadcrumb trail) of where the snow plow has been. This app can also be used by Maintenance personnel to locate and track the current location of snow plows and to see where they have been.
Travel Advisory Telephone System (TATS) Reporting
Travel Advisory Telephone System (TATS) Reporting
UDOT maintenance personnel in mountainous areas are asked to call into the UDOT weather desk twice a day to report on road and weather conditions during active storms. This information is then provided to the travel advisory group providing information to the traveling public. Information reported includes:
LOI #08-2 Winter Weather Reporting
Road Conditions - dry, wet, snow packed, icy
Weather Conditions
Precipitation - the form and the amount
Temperatures being observed
Active winter operations taking place
Snow and Ice Performance Measure
Snow and Ice Performance Measure
The UDOT snow and ice performance measures were implemented in 2016 to evaluate weather and road conditions facing UDOT maintenance crews in real time using UDOT’s existing Road Weather Information System (RWIS). The data gathered from RWIS stations is used to evaluate the condition of a particular section of roadway during storm events (See Figure 8.4.1 for RWIS instrumentation)
This reporting system is referred to as the snow and ice performance measure. UDOT has established a performance measure of a “B” as an acceptable grade during active storm events. Below is an explanation of the data that is captured by the RWIS stations, how the data is used to calculate a letter grade and how frequently the data is being captured.
Data that is collected every 10 minutes from the Roadway Weather Information Systems:
Air temperature & relative humidity are combined to arrive at a wet-bulb temperature
The wet-bulb temperature (WBT) is the temperature read by a thermometer covered in a water-soaked (water at ambient temperature) cloth (a wet-bulb thermometer) over which air is passed.[1] At 100% relative humidity, the wet-bulb temperature is equal to the air temperature (dry-bulb temperature); at lower humidity the wet-bulb temperature is lower than dry-bulb temperature because of evaporative cooling.
Visibility and precipitation occurrence are combined to generate a snowfall rate
Wind speed/gust/direction
Road condition/ road grip/ road temperature
Freezing rain
Once the data is collected, it is used to calculate a Storm Intensity Index (SII). See Figure 8.4.2 for Storm Intensity Index.
Figure 8.4.1 Roadway Weather Information Systems (RWIS)
Figure 8.4.2 Storm Intensity Index Formula
The Storm Intensity Index is compared to the resulting road grip or road condition (as being measured by non-evasive road sensors) to provide an overall performance based on observations from the RWIS stations (See Figure 8.4.3)
Figure 8.4.3 Snow and Ice Performance Measure - Show SII vs. Road Grip
For a given storm, the number of observations that are green or yellow on the matrix cube (See Figure 8.4.5), or inversely, the number of red observations are used to calculate the score. For a winter season, it is the aggregate of these storm observations. If a storm received an 85%, that means 15% of the observations during that storm reported a snowy, icy, or slushy road when it was deemed there should have been better road conditions based on the weather at that time. For this scenario the overall performance would receive a “B” grade (see Table 8.4.4).
Figure 8.4.4 Letter Grades Based on Observations
Figure 8.4.5 Matrix Cub - Snow and Ice Performance Measure - Conceptual diagram of maintenance crew performance with the measured road condition on the y-axis and the Storm Intensity Index (SII) on the y-axis. Two SII thresholds are shown; if snow is falling greater than one inch per hour (with a road temperature and wet-bulb temperature of less than 32 degrees with light winds) and the road condition being reported is snow-covered, then maintenance performance would be “acceptable” (falling in the yellow box in the top left corner). If road conditions are being reported as wet under the same weather conditions (SII), then maintenance performance would be exceeding expectations
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When the SII is above one (or when it is snowing heavier than one inch per hour at a temperature of 32 degrees or less and light winds), maintenance performance is either acceptable or exceeding expectations depending on the road condition. When it is lightly snowing and roads are snow-covered, maintenance performance is deemed “unacceptable”. Figure 8.4.6 below highlights the relationship between the SII and the road condition.
A storm duration is defined as starting an hour before the storm intensity index reaches 0.25 and extending until the storm intensity index reaches zero for a period of 12 hours (see Figure 8.4.6).
Figure 8.4.6 Automated Storm Identification
The snow and ice performance measure is able to display data where an RWIS station currently exists. The snow and ice performance measure can be accessed at the following link: http://udottraffic.utah.gov/forecastview/ssipdashboard.aspx
Figure 8.4.7 Snow and Ice Performance Dashboard
The left side of figure 8.4.7 shows the current locations of the RWIS Systems throughout UDOT’s networks. Additional information can be accessed by clicking on RWIS Station. By clicking on a RWIS Station, the user can see the current weather conditions or select a time and date range to view the results for a particular segment of roadway (as seen in Figure 8.4.8). The snow and ice performance measure is also able to show the presence of snow plows and when they were actively plowing on a particular route (see Figure 8.4.8) when the SII is selected as the Y axis condition.
Figure 8.4.8 Snow and Ice Performance Measure - Presence of Snowplows
Conditions from a single site can be analyzed in real-time or in the past in depth from UDOT’s statewide maintenance forecast page (http://udottraffic.utah.gov/ForecastView; (Figure 8.4.7) or multiple sites can be analyzed quickly in real-time from UDOT’s new storm management page (Figure 8.4.9). Automatic Vehicle Location (AVL) can track snow plows via this page and shed forecasts can be viewed by maintenance personnel so resource allocation can be assessed during storms for the most efficient plowing of roads. Post-storm analysis can also be completed to further evaluate resource allocation for future storms as well as budget justification.
Figure 8.4.9 Snow and Ice Performance Measure - Multiple Station
Statewide performance can also be assessed via the snow and ice performance dashboard (http://udottraffic.utah.gov/forecastview/ssipdashboard.aspx). Current accumulated performance from every RWIS through a given winter as well as monthly breakdowns can be displayed on this page. Future improvements will allow this page to show accumulated performance from a highway, region, area, or shed level. New RWIS will also continue to be installed across the state and current RWIS will be upgraded (an upgraded site is shown in Figure 8.4.10).
Figure 8.4.10 - Statewide Snow and Ice Performance Dashboard
The snow and ice performance dashboard is a powerful tool that can assist maintenance personnel in evaluating their performance based on the intensity of storms throughout the year.
To get a better understanding of how the snow and ice performance metrics works and how it can be used by maintenance personnel, please refer to the following presentations from the UDOT Weather Group:
UDOT’s Weather Group presented at the 2018 UDOT Annual Conference
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