The following documentation describes the structure and
fields contained within the sensor feed from the Iowa DOT. The Iowa
DOT has sensors deployed across the state, primarily in urban area
and work zones. This sensor feed has data from all sensors and is
updated every minute with the current speed, count, occupancy and
classification. In addition to the sensor data, corresponding
location and sensor types is also included in the field which can
be used to identify the type of sensor, what lanes of data are
collected, the roadway data was collected on, the direction of
travel and location of the sensor.
Sensor Feed Structure
Below is the structure of the sensor feed with the
corresponding parents and nodes. This should be used for reference
to understand how the data is structured for each detector.
Description of Data
The following section provides a description of the
nodes/fields within the sensor data feed. The section is divided
into two section: Context Data and Detector Data. The context data
is relevant for all of the sensors which provides organization
information and the corresponding time stamps of the data. The
detector data section provides unique information and current data
for each detector. The unique information describes the location of
the sensor including coordinates, the roadway data was collected
for, the direction of travel, etc. The current data includes speed,
occupancy, count and classification for all lanes the detector
collects as well as the individual lane level data.
The first fields provide the organization and time stamp for
the detector data:
- The organization collecting the data (Will always be
- The network within the organization collecting the data
(Will always be IADOT-SIMS)
- This is the parent/array for the following fields
containing the data and timestamp of the data.
- Date for the data requested in the format YYYYMMDD
- The timestamp the data was requested in the format
- Provides the offset from UTC that is used for
- The begin time of data collected in the format HHMMSS
- The end time of data collected in the format HHMMSS
The remaining fields are collected for each detector across
the state and located within the parent-node(XML)/array(JSON)
- contains a list of all of the detectors statewide and
the corresponding data for each detector. The remaining nodes
are all within this parent/array.
- Provides the status of the sensor. Status options are:
operational, off or failed.
- Reserved field for identifying whether the sensor is
located within a work zone. Not currently used.
- The unique name for each detector station.
The following fields provide the coordinates and datum for the
- Latitude coordinate.
- Longitude coordinate.
- Datum used with coordinates.
- The ownership of the roadway the sensor is detecting
- The roadway the sensor is detecting data for.
The following fields provide the Iowa DOT LRS values.
- This is a reserved fields for the LRS routeId for
- This is a reserved fields for the LRS measure value
for future use
- The type of detector used to collect data
- The direction of travel collected by the sensor.
- The type of lanes collected by the sensors. Some
examples include: through lanes, right exit ramp, right entrance
The remaining fields include the data collected by the sensor
including speed, count, occupancy and classification.
- The total number of vehicles detected. To convert to
hourly volumes, multiply by 60.
- The average occupancy of all lanes.
- The average speeds of all lanes in mph.
- The total number of small vehicles detected.
- The total number of medium vehicles detected.
- The total number of large vehicles detected.
- lanes (XML:parent/JSON:array)
The following fields separate the data collected by the
sensor by lane. The number of lanes will vary based on the
- The average speed of vehicles detected in the
lane-id identified in mph.
- The lane-id for the data collected. The number
of lane-id’s will vary based on the detector. Typically
lane numbering will start from the median. So lane-id 1
will be the left-most lane and continue to the shoulder.
- The number of vehicles detected in the lane-id
identified. To convert to hourly volumes, multiply by
- The average occupancy in the lane-id identified.
- The count of small vehicles detected in the
- The count of medium vehicles detected in the
- The count of large vehicles detected in the