SCAN Glossary

Contents:


Data Definitions:

Pavement Table Data Definitions
Data Type Abbr. Definition
Surface Status Status Condition of the pavement surface
Surface Temperature Sfc Temperature of the pavement sensor roughly 3 mm (1/8 inch) below the surface of the sensor.
Subsurface Temperature Sub Typically, the temperature approximately 43 cm (17 inches) below the top of the pavement. You can place additional subsurface sensors at different depths to monitor frost depth.
Subsurface Moisture Moisture The sub-surface moisture expressed as a percentage (eg. 0 indicates dry, 100 indicates saturated). This value is only displayed for NTCIP sites configured with the appropriate sensor.
Delta Time Delta T Raw measurement from the Time Domain Reflectometry MP-917 Soil Moisture probe. This value is only displayed for NTCIP sites configured with the appropriate sensor.
Freeze Point Frz Freezing point of the moisture on the pavement sensor based upon the specific chemical in use. This field is reported when the surface status is Wet, Chemical Wet, or Snow/Ice Warning. Only reported by the FP2000 and active sensors.
Chemical Percent Chem Percent of chemical saturation in the moisture. This field is reported when the surface status is Wet, Chemical Wet, or Snow/Ice Warning. Only reported by the FP2000 sensor.
Ice Percentage Ice Percent of ice in the moisture. When ice percentage is roughly 50% to 85%, you would typically call the surface moisture "slush". This field is reported when the surface status is Wet, Chemical Wet, or Snow/Ice Warning. Only reported by the FP2000 sensor.
Depth Dpth Depth of water layer on the sensor. This field is reported when the surface status is Wet, Chemical Wet, or Snow/Ice Warning and the surface temperature is above the freeze point temperature. Only reported by the FP2000 sensor.
Chemical Factor CF Relative indication of chemical present in the moisture on the surface. Chemical factor uses a relative scale ranging from 0 to 100.
Conductivity Cond The conductance of the ice/liquid mixture on the pavement. This value is only displayed for NTCIP sites configured with the appropriate sensor.
Salinity Salin Salinity is roughly the number of grams of dissolved matter per kilogram of seawater. Units shown in parts per 100,000. This value is only displayed for NTCIP sites configured with the appropriate sensor.
Surface Status Definitions
The following surface status codes are listed in order of severity with the most critical status listed first. Third party vendors may calculate surface conditions differently. Please contact your equipment vendor for details.
Status Description
Snow/Ice Warning Continuous film of ice and water mixture at or below freezing (32F / 0C) with insufficient chemical to keep the mixture from freezing.
This status can only be reported at SSI ESP and SP sites when precipitation occurs.
Ice Warning Continuous film of ice and water mixture at or below freezing (32F / 0C) with insufficient chemical to keep the mixture from freezing.
This status can only be reported at NTCIP sites.
Snow Warning This status can be reported at NTCIP sites, but will not be reported by SSI NTCIP sites.
Wet Below Freezing Moisture on pavement sensor with a surface temperature below freezing (32F / 0C).
This status will only be reported at SSI SCAN Detector sites.
Ice Watch Thin or spotty film of moisture at or below freezing (32F / 0C).
This status can only be reported at NTCIP sites when precipitation is not occurring.
Snow/IceWatch Thin or spotty film of moisture at or below freezing (32F / 0C).
This status can only be reported at SSI ESP and SP sites when precipitation is not occurring.
Snow Watch This status can be reported at NTCIP sites, but is not detected at SSI NTCIP sites.
Frost Moisture on pavement at or below freezing (32F / 0C) with a pavement temperature at or below the dew point temperature.
This status can only be reported by SSI ESP, SP, and NTCIP sites when precipitation is not occurring.
Chemical Wet Continuous film of water and ice mixture at or below freezing (32F or 0C) with enough chemical to keep the mixture from freezing.
This status can only be reported by SSI ESP, SP, and NTCIP sites when precipitation occurs.
Wet Continuous film of moisture on the pavement sensor with a surface temperature above freezing (32F or 0C).
This status can be reported by SSI ESP, SP, SCAN Detector, and NTCIP sites when precipitation has occurred.
Damp Thin or spotty film of moisture above freezing (32F or 0C).
This status can only be reported by SSI ESP, and SP sites when precipitation is not occurring.
Trace Moisture Thin or spotty film of moisture above freezing (32F or 0C). Surface moisture occurred without precipitation being detected.
This status will only be reported at NTCIP sites when precipitation is not occurring.
Absorption at Dew Point, Absorption, & Dew These statuses can be reported at NTCIP sites, but are not currently detected at SSI NTCIP sites.
Dry Absence of moisture on the surface sensor.
This status can be reported by SSI ESP, SP, SCAN Dectector, and NTCIP sites.
Other Other is the standard NTCIP ESS surface condition code to handle conditions not explicitly included in this table. This status will only be reported NTCIP by sensors installed at NTCIP ESS sites.
No Report The surface sensor is not operating properly and requires maintenance.
This status will only be reported by SSI ESP and SP sites.
Error The surface sensor is not operating properly and requires maintenance.
This status will only be reported by NTCIP sites.
Atmospheric Data Definitions
Data Type Abbr. Definition
Air Temperature Air Air temperature at the site.
Max Temp Max The maximum temperature recorded during the 24 hours preceding the observation. This value is only displayed for NTCIP sites configured with the appropriate sensor.
Min Temp Min The minimum temperature recorded during the 24 hours preceding the observation. This value is only displayed for NTCIP sites configured with the appropriate sensor.
Dew Point Temperature Dew Temperature at which the air becomes saturated as it cools. If the road or runway temperature drops to or below the dew point, moisture may develop on the surface. The form the moisture takes depends on the surface temperature and the amount of chemical present.
Relative Humidity RH Percent of moisture in the air. A relative humidity of 0% shows that the air contains no moisture and 100% shows that the air is completely saturated and cannot absorb more moisture.
Wind Chill Factor WndChll Forecasted Wind Chill Factor.
Heat Index Heat Forecasted Heat Index.
Wind Speed SpdAvg Average speed of the wind during an evaluation cycle.
Wind Direction DirAvg Average wind direction during an evaluation cycle. Wind direction can be displayed in two formats: cardinal points or degrees. Cardinal format has 8 possible headings. Degree format displays wind direction in values ranging from 1 to 360.
Direction Cardinal Format Degree Range
North N 338 - 22
Northeast NE 23 - 68
East E 69 - 112
Southeast SE 113 - 158
South S 159 - 202
Southwest SW 203 - 248
West W 249 - 292
Northwest NW 293 - 337
Gust SpdGst Maximum wind speed measured during an evaluation cycle. The time period over which wind gust speed is monitored can vary based on the type and manufacturer of the RWIS site.
Probability of Precipitation Prob Likelihood of precipitation during a forecasted period.
Cloud Cover Cloud Cover Forecasted cloud cover percentage during a period.
Precipitation Type Precip Type of precipitation detected by a precipitation sensor, if one is available. Certain types of precipitation sensors can only detect the presence or absence of precipitation and will display Yes or No. Other types of precipitation sensors, such as the Weather Identifier and Visibility Sensor (WIVIS) or Optical Weather Identifier (OWI), can classify the type of precipitation and will report a specific type of precipitation. The WIVIS and OWI precipitation sensors may report Yes at the onset of precipitation until sufficient time has elapsed to classify the precipitation type.
Precipitation Rate Rate Average precipitation rate computed every minute. Snowfall is converted to water equivalent and the rate represents the rate of liquid equivalent.
Precipitation Intensity Intens Intensity of the precipitation as derived from the precipitation rate. The National Weather Service defines the following intensity classes: light, moderate, or heavy.
Time Since Last Precip TimeSince The time interval since the last precipitation event occurred. This value is not supported for NTCIP sites.
Precipitation Start Time StartTime The time at which the most recent precipitation event began. This value is only displayed for NTCIP sites configured with the appropriate sensor.
Precipitation End Time EndTime The time at which the most recent precipitation event ended. This value is only displayed for NTCIP sites configured with the appropriate sensor.
Precipitation Accumulation Accum Rainfall amount or snowfall liquid equivalent for the period from midnight GMT to the current time. At midnight GMT the total accumulation is reset to zero. See the accumulation definitions below for the proper NTCIP accumulation definitions.
Snow Depth Snow Depth The depth of snow on representative areas other than the highway pavement, avoiding drifts and plowed areas. Snow depth is only supported at NTCIP sites.
Snow Accumulation Snow Accum Forecasted snowfall accumulation during a forecast period.
10 Minute Precip Accum 10 min Rainfall amount or snowfall liquid equivalent for the previous 10 minute period. This value is only displayed for NTCIP sites configured with the appropriate sensor.
1 Hour Precip Accum 1hr Rainfall amount or snowfall liquid equivalent for the previous 1 hour period. This value is only displayed for NTCIP sites configured with the appropriate sensor.
3 Hour Precip Accum 3hr Rainfall amount or snowfall liquid equivalent for the previous 3 hour period. This value is only displayed for NTCIP sites configured with the appropriate sensor.
6 Hour Precip Accum 6hr Rainfall amount or snowfall liquid equivalent for the previous 6 hour period. This value is only displayed for NTCIP sites configured with the appropriate sensor.
12 Hour Precip Accum 12hr Rainfall amount or snowfall liquid equivalent for the previous 12 hour period. This value is only displayed for NTCIP sites configured with the appropriate sensor.
24 Hour Precip Accum 24hr Rainfall amount or snowfall liquid equivalent for the previous 24 hour period. This value is only displayed for NTCIP sites configured with the appropriate sensor.
Barometric Pressure BaroPs The force per unit area exerted by the atmosphere. This reading is not adjusted for site elevation.
10 Minute Solar Radiation 10 Min Rad The direct solar radiation integrated over the preceding 10 minutes. This value is only displayed for NTCIP sites configured with the appropriate sensor.
24 Hour Solar Radiation 24 Hr Rad The direct solar radiation integrated over the preceding 24 hours. This value is only displayed for NTCIP sites configured with the appropriate sensor.
Total Sun Sun The total amount of sunshine in minutes over the preceding 24 hours. This value is only displayed for NTCIP sites configured with the appropriate sensor.
Visibility Vis Average distance that you can see, both day and night, computed every three minutes.
Wet Bulb Temp. WtBlb The wet bulb temperature is the temperature of a thermometer whose bulb is wrapped in wet muslin. The wetbulb is always in between the temperature and dew point, except at saturation, when all three are equivalent. This value is only displayed for NTCIP sites configured with the appropriate sensor.
Water Level Height Water level height is the relative water level height from the water level sensor's calibrated "normal" height.
Ozone Ozone Concentration of ozone in the air as a fraction of volume. Shown in parts per billion.
Bridge Sprayer Data Definitions
The following Bridge Sprayer definitions only apply to NTCIP sites.
Data Type Abbr. Definition
Sprayer Status Status Status of the bridge sprayer control system.
Last Activation Last Activation Date and Time the RWIS requested the bridge sprayer to be activated.
Start Time Start Time Date and time the bridge sprayer began the chemical application cycle. Start Time will only be reported for bridge sprayers configured to provide sprayer feedback to the RWIS site.
End Time End Time Date and time the bridge sprayer completed the chemical application cycle. End Time will only be reported for bridge sprayers configured to provide sprayer feedback to the RWIS site.
Tank Level Tank Level

The amount of deicing chemical remaining in the bridge sprayer holding tank. Tank Level is only reported by a bridge sprayer connected via a Bridge Sprayer Controller.

Tank Level Start Start The amount of deicing chemical present in the bridge sprayer holding tank at the start of a spray event.  Only reported by a bridge sprayer connected via a Bridge Sprayer Controller.
Tank Level End End The amount of deicing chemical present in the bridge sprayer holding tank at the completion of a spray event.  Only reported by a bridge sprayer connected via a Bridge Sprayer Controller.
Tank Level Amount Amount The amount of deicing chemical used during a spray event.  Only reported by a bridge sprayer connected via a Bridge Sprayer Controller.
Line Pressure Line Pressure The line pressure reported by the bridge sprayer in pounds per square inch. Line Pressure is only reported by a bridge sprayer connected via a Bridge Sprayer Controller.
Average Line Pressure Average The average line pressure reported by the bridge sprayer during a spray event.  Only reported by a bridge sprayer connected via a Bridge Sprayer Controller.
Low Line Pressure Low The lowest line pressure reported by the bridge sprayer during a spray event.  Only reported by a bridge sprayer connected via a Bridge Sprayer Controller.
High Line Pressure High The highest line pressure reported by the bridge sprayer during a spray event.  Only reported by a bridge sprayer connected via a Bridge Sprayer Controller.
Flow Since Last Event Flow Since The amount of chemical that has leaked (as reported by the flow sensor) since the completion of the last spray event. This counter will reset after each firing and when the sprayer or RPU is restarted. This value is only reported by a bridge sprayer connected via a Bridge Sprayer Controller.
Average Flow Rate Average The average chemical applied per minute by the bridge sprayer during a sprayer event.  Only reported by a bridge sprayer connected via a Bridge Sprayer Controller.
Low Flow Rate Low The lowest flow rate reported by the bridge sprayer during a sprayer event.  Only reported by a bridge sprayer connected via a Bridge Sprayer Controller.
High Flow Rate High The highest flow rate reported by the bridge sprayer during a sprayer event.  Only reported by a bridge sprayer connected via a Bridge Sprayer Controller.
Requested by Requested by The user that manually requested a bridge sprayer configuration change.
User Activation User Activation The user that manually requested a bridge sprayer activation.
Request Date/Time Request Date/Time The date and time that a bridge sprayer configuration change was requested by a user.
Effective Date/Time Effective Date/Time The date and time that a user requested bridge sprayer configuration change was delivered to the RWIS site. An * will be displayed if the configuration was not delivered to the site.
Sprayer Mode Mode Bridge sprayers can be configured in one of three modes: Automatic, On Demand, and Disabled. Automatic mode also allows On Demand requests from the Bridge Sprayer Activation page.
Max Operating Temperature Max Temperature The upper bound of the operational surface temperature range that controls whether the bridge sprayer can be automatically activated.
Min Operating Temperature Min Temperature The lower bound of the operational surface temperature range that controls whether the bridge sprayer can be automatically activated.
Wind Speed Hold Off Wind Speed Hold Off The maximum wind speed under which the bridge sprayer is configured to automatically activate.
Freeze Temperature Offset Freeze Temp Offset Activate sprayer when the surface temperature is within this many degrees or is less than the freeze point. A negative value can be specified to delay the automatic activation of the sprayer.
Freeze Condition Hold Off Freeze Hold Off Number of minutes required to elapse before reactivating the sprayer due to a freeze condition.
Dew Point Offset Dew Point Offset Activate sprayer when the surface temperature is within this many degrees or is less than the dew point. A negative value can be specified to delay the automatic activation of the sprayer.
Frost Condition Hold Off Frost Hold Off Number of minutes required to elapse before reactivating the sprayer due to a frost condition.
Bridge Sprayer Status Definitions
The following bridge sprayer status codes are only supported for bridge sprayers installed at NTCIP sites.
Sprayer Status Description
Spraying Feedback status from the bridge sprayer indicates the sprayer is currently applying chemical. This status will be reported after each activation status listed below or if the sprayer has been activated from an external source. The sprayer must provide activation feedback to report this status.
Waiting for confirmation to spray Before a request for sprayer activation occurs, the RPU must detect conditions that meet one of the automatic sprayer activation definitions for two consecutive sensor evaluation cycles. This status will be reported when the RPU initially detects the conditions. Once the conditions are confirmed, the RPU will request the sprayer is activated and the proper activation status will be displayed.
Spraying Completed The bridge sprayer has completed a spraying cycle. This status will be reported upon completion of each sprayer activation. The sprayer must provide activation feedback to report this status.
Active due to manual user request A user manually requested a sprayer activation. Manual requests can be initiated from the Bridge Sprayer Activation page or directly from maintenance mode at the site.
Active due to freeze point condition The RPU initiated a sprayer activation because the surface temperature is within the user specified temperature range or is less than the freeze point temperature. A negative value can be specified to delay the automatic activation of the sprayer. This status will only occur when the user specified average wind speed threshold has not been exceeded, the current surface temperature falls within the user defined operating surface temperature range, and the user defined freeze point condition hold off time has expired.
Active due to frost condition The RPU initiated a sprayer activation because the surface temperature is within the user specified temperature range or is less than the dew point. A negative value can be specified to delay the automatic activation of the sprayer. This status will only occur when the user specified average wind speed threshold has not been exceeded, the current surface temperature falls within the user defined operating surface temperature range, and the user defined frost condition hold off time has expired.
Active due to rain and wet surface conditions The RPU initiated a sprayer activation because the surface temperature is within the user specified temperature range or is less than freezing and rain is occurring. Moisture must also be present on the pavement. A negative value can be specified to delay the automatic activation of the sprayer. This status will only occur when the user specified average wind speed threshold has not been exceeded, the current surface temperature falls within the user defined operating surface temperature range, the user defined precipitation condition hold off time has expired, and the automatic precipitation activation option has been enabled.
Active due to freezing rain condition The RPU initiated a sprayer activation because the surface temperature is within the user specified temperature range or is less than freezing and freezing rain is occurring. Moisture must also be present on the pavement. A negative value can be specified to delay the automatic activation of the sprayer. This status will only occur when the user specified average wind speed threshold has not been exceeded, the current surface temperature falls within the user defined operating surface temperature range, the user defined precipitation condition hold off time has expired, and the automatic precipitation activation option has been enabled.
Active due to snow condition The RPU initiated a sprayer activation because the surface temperature is within the user specified temperature range or is less than freezing and snow is occurring at a rate greater than .2"/hr (5mm/hr). A negative value can be specified to delay the automatic activation of the sprayer. This status will only occur when the user specified average wind speed threshold has not been exceeded, the current surface temperature falls within the user defined operating surface temperature range, the user defined precipitation condition hold off time has expired, and the automatic precipitation activation option has been enabled.
Inactive due to high surface temperature The RPU will not initiate a sprayer activation because the current surface temperature is warmer than the user defined surface temperature operating range.
Inactive due to low surface temperature The RPU will not initiate a sprayer activation because the current surface temperature is colder than the user defined surface temperature operating range.
Inactive due to high winds The RPU will not initiate a sprayer activation because the average wind speed is exceeding the user defined maximum wind speed.
Inactive due to freeze point hold off time The RPU will not initiate a sprayer activation because the user specified freeze condition hold off time has not yet expired.
Inactive due to frost hold off time The RPU will not initiate a sprayer activation because the user specified frost condition hold off time has not yet expired.
Inactive - critical conditions not detected The RPU will not initiate a sprayer activation because the user specified freeze and frost conditions are not being reported.
Sprayer currently disabled per user request The bridge sprayer has been disabled and cannot be automatically activated or manually activated on-demand until the sprayer is enabled.
The sprayer was triggered by the RWIS; however, the sprayer did not respond. An activation request was sent to the bridge sprayer; however, the bridge sprayer was not activated.
Camera Configuration Definitions
Cameras supporting multiple camera positions are only supported for NTCIP sites.
Data Type Abbr. Definition
Request Date/Time Request Date/Time The date and time that a camera configuration change was requested by a user.
Requested by Requested by The user that manually requested a camera configuration change.
Effective Date/Time Effective Date/Time The date and time that a user requested camera configuration change was delivered to the RWIS site. An * will be displayed if the configuration was not delivered to the site.
Camera Positions Camera Positions List containing all of the enabled camera positions at an NTCIP site.
Device Data Definitions
Devices using basic relay control are not supported for NTCIP sites.
Generic Devices are only supported for NTCIP site.
Data Type Abbr. Definition
Status Status Status displays whether a device using basic relay control is currently "On" or "Off".
Set By / Requested By Set By Identifies the source that last controlled the device. "RPU" will be shown when the RPU determined that the device's state should have been set.
Command Command Identifies any user initiated device command that was sent from a user application.
Mode Mode Mode identifies the control mode the site is using to control the generic device. Supported modes are "Automatic" and "Manual". "Other" will be reported during the site restart process. Mode is only supported on NTCIP sites.
Control State Control State Control State displays the current state the RPU is sending to the generic device. The states are configurable per site and are only supported on NTCIP sites.
Device Status Device Status Device Status displays whether the generic device is either "On" or "Off", experiencing an "Error" condition, or in a transitional "Pending" state. "Other" will be reported during the site restart process. These status codes are only available on NTCIP sites.
Request Date/Time Request Date/Time The date and time that a generic device mode or control state change was requested by a user.
Effective Date/Time Effective Date/Time The date and time that a user requested a generic device mode or control state change was delivered to the RWIS site. An * will be displayed if the request was not delivered to the site.
Last State Change Last State Change The date and time the Control State was last sent by the RPU to the generic device.
Last Status Change Last Status Change The date and time of the last change in Device Status.
Traffic Data Definitions
Data Type Abbr. Definition
Mode Mode Describes the configuration of the traffic sensor. The EIS RTMS traffic sensor supports three modes: Side-fired, Forward-fired In, Forward-fired Out. A permanent count station only supports the In Lane mode.
  • Side-fired is configured to shoot across traffic lanes and can be configured to monitor up to eight different traffic lanes.
  • Forward-fired In is configured to monitor a single traffic lane where traffic is traveling toward the sensor.
  • Forward-fired Out is configured to monitor a single traffic lane where traffic is traveling away from the sensor.
  • In Lane is specifies the mode for permanent count stations.
Time Interval TimInt Identifies the length of a single collection interval for the sensor in seconds.
Forward Average Speed FwdAvgSpd The average vehicle speed as a vehicle traveled through all traffic zones. Forward Average Speed is only collected in a Forward-fired configuration.
Average Traffic Speed TrfSpd The average vehicle speed calculated as a vehicles travel though each traffic zone.
Total Volume TotalVolume Total number of vehicles that were detected passing through a traffic zone.
Normal Volume NormVol Number of normal length vehicles that were detected passing through a traffic zone.
For EIS sensors configured for foreward fire, the normal volume shown will represent all vehicles passing through the traffic zone since long volume will not be reported.
Long Volume LongVol Number of large vehicles (such as eighteen wheel trucks) that were detected passing through a traffic zone. This value is only available in a side-fired configuration. A Side-fired configuration can only be configured to support Long Volume or Average Headway, but not both.
Unclassified Volume Unclass Number of vehicles that were detected passing through a traffic zone where the speed or length of the vehicle could not be determined.
Occupancy Occup Percentage of time that a traffic zone is occupied.
Average Headway AvgHeadway Time interval between vehicles. This value is only available in a side-fired configuration. A Side-fired configuration can only be configured to support Average Headway or Long Volume, but not both.
Battery Voltage Battery Reports the remaining battery voltage. This value is only available for a permanent count station.
Speed Count Speed Bin Name Counts the number of vehicles for each speed range. This value is only available for a permanent count station.
Classification Count Classification Bin Name Counts the number of vehicles for each classification range. This value is only available for a permanent count station.

Terms

GMT:
A time standard which uses the local time of Greenwich, England known as Greenwich Mean Time. It is one of the time standards used in meteorology, and it is 4 hours ahead of EDT (5 hours ahead of EST) - 00:GMT is equal to 8 pm EDT (5 pm PDT), 12:GMT is 8 am EDT (5 am PDT). You might also see GMT listed as Z, Zulu time, or UTC, Universal Coordinated Time.

RPU:
Remote Processing Unit

RWIS
:
Road and Runway Weather Information System

SCAN*Cast:
Surface Systems' weather and pavement forecast service.