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      Speed Limit Difference Layers

      A summary of Speed Limit Difference data layers that can be analyzed within Insights.

      1.0 Selectable Layers

      The following are Speed Limit Difference data layers that can be selected within Insights including:

      • Average Difference: Quantifies the difference between the speed limit and average speed of observed trips along a road segment. It is provided in miles per hour (mph).
      • 50th Percentile Difference: Quantifies the difference between the speed limit and the speed at or below which 50% of observed trips travel along a road segment. It is provided in miles per hour (mph).
      • 85th Percentile Difference: Quantifies the difference between the speed limit and the speed at or below which 85% of observed trips travel along a road segment. It is provided in miles per hour (mph).
      • 95th Percentile Difference: Quantifies the difference between the speed limit and the speed at or below which 95% of observed trips travel along a road segment. It is provided in miles per hour (mph).

      ⚠️NOTE: For customers with integrated speed limit data: If not all streets are updated, the difference layers will use available speed limits, or the Urban SDK Speed Limit as needed.

      2.0 Map View

      When selecting one of the Traffic Speed Difference layers, the map will color-code the road links based on their speed difference value across the entire selected time period.  For instance, if a customer selects to view data for the month of October 2023 and selects the Average Speed Difference layer, the colors on the road links will represent the difference in Average Speeds, relative to the posted Speed Limit, across the entire month.

      Speed Limit Difference Legend

      The following legend categories are used by default to color the data according to the speed limit difference across all Speed Limit Difference layers:

      Category Values (mph)
      1 >5 mph below
      2 0-5 mph below
      3 0-5 mph above
      4 5-10 mph above
      5 10-15 mph above
      6 >15 mph above

      3.0 Tool Tip

      In map view, customers can hover over a road link to highlight it and view key statistics in a Tool Tip pop-up. The pop-up displays speed limit difference values for the selected layer by direction.

      4.0 Data Panel

      While a data layer is selected and visible in the Map View, customers can select individual road segments to bring up the Data Panel which consists of two tabs: the Analytics Tab, and the Details Tab.

      4.1 Analytics Tab: 

      The analytics tab includes data insights on the selected road segment.

      4.1.1 Directional Selection:

      For roadways that are presented on the map as one link representing both directions of travel, a blue dropdown button will be available at the top of the data pen enabling you to select a specific direction, or the aggregated values of both directions.

      4.1.2 Summary Scorecard:

      A summary scorecard of Traffic Speed Limit Difference Data across the selected time period will be shown at the top of the data panel (shown below). 

      4.1.2 Chart:

      Shows a heat map of the selected layer value disaggregated to your selected time period. The values within the heat map chart are colored based on the min and max values within the chart across the entire week. Values that appear darker reflect values that are closer to the minimum, and values that are whiter, represent values that are closer to the maximum.

      💡Tip: The chart colors are designed to make it easy to quickly pinpoint the periods of the day where values are highest or lowest, as well as at what times those anomalies occur.

      4.2 Details Tab:

      This includes a summary of meta data for the selected road segment including:

      • Road Segment ID: unique ID for the road segment that can be referenced across all Urban SDK data.

      • Location: what county the segment resides within

      • Functional Class: classifies whether the roadway is a highway, arterial, or local street.

      • Length: the length of the road segment in miles.

      • Road Name: the name of the road.

      • Speed Limit: the posted speed limit based on data integrated within your customer account.