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Network Screening Segments - App Overview

This article provides an overview of the Network Screening - Segments application, its purpose, and the outputs that can be generated in it.

Greg Olsen avatar
Written by Greg Olsen
Updated over a week ago

The Network Screening application is designed to help users rank and identify sites for further investigation and potential treatment along the entire roadway network in an easy-to-use interface.

The Network Map displays the ranked segments/intersections, color-coded according to standard deviation. With Green representing the lowest value, yellow representing the mean (+1 standard deviation), and red representing the second standard deviation (Mean + 2 standard deviation).

(A network screening, with the Network Map displaying the ranked segments)

The Network Screening application has 5 key features: View/Modify Date Extents, Attribute Search, Segment Flyout, Roadway Ranking, Contextual Data, and the Network Screening Report. Each feature is discussed in more detail below.

View/Modify Date Extents

When conducting a Network Screening, it is easy to see what dates of historical crash data are being used to generate your screening results. By checking the Date Extents, located in the top right corner of the screen, you can see what dates of data are being utilized in your screening.

To modify the dates, click on the Date Extents in the menu bar, and select the date range you would like to include in your screening.

If Predictive Analysis is enabled for your organization, you will also be able to select the pre-defined Observed and EB Adjusted Data date range for your screening. (Note: Empirical Bayes adjusted performance measures are only available when selecting one of the Observed and EB Adjusted Data date ranges).

(The Date Range box displaying two Observed and EB Adjusted date ranges.)

Performance Measures

Rank your selected roadway by the following Performance Measures:

  • Crashes

  • Fatal Crashes

  • Crash Rate

  • Crashes per mile

  • ePDO

  • SPF Prediction*

  • SPF Predicted Rate*

  • EB Expectation*

  • EB Expected Rate*

  • PSI Potential*

  • PSI Potential Rate*

  • SPF Prediction Per Mile*

  • EB Expectation Per Mile*

  • PSI Potential Per Mile*

(* indicates that an agency-specific SPF is required for this calculation. SPFs can be generated, and managed through the Predictive Analysis application)

A comprehensive list of how each ranking criteria is calculated can be found in the Numetric Calculations Overview article.

Network Screening - Segments will only load the top 1,000 segments that meet your ranking and filter criteria. A more comprehensive list of all intersection rankings is available in the CSV download.

(A segment ranking window with the selected segments ranked by Crash Rate, with Crashes Per Mile, also displayed.)

Limiting Values

Many performance measures can be modified to include a limited ranking value. When defined, only segments with a value that meets or exceeds the defined minimum value will be displayed in the ranking table, and screening map. By default each value is set to 0, meaning that every segment will be displayed. To modify the limiting value, click the Settings button located in the top right corner of the screen, next to the Save button, and enter the minimum value for the desired ranking criteria.

(The Settings flyout with the Limiting Values displayed. In this example, a minimum Level of Service Of Safety (LOSS) is being defined as III, meaning only segments with a LOSS value of III or more will display.)

Attribute Search

Use Numetric’s powerful text-to-search feature to run custom roadway Network Screening requests. Search by recommended countermeasure, crash type, or any other crash or roadway attribute, and generate instant roadway rankings that tell you which roadways require your attention.

(A Segment Screening for a given county including only fatal and serious crashes, ranked by Crash Rate.)

Map Settings

Clicking on the Map Settings icon (the gear icon located in the top right corner of the map) will allow you to customize your map settings, including the auto-zoom, and satellite view. These settings will save and become your default map settings whenever you log in.

(The Map Settings section of a Network Screening map)

Segment Flyout

Clicking on any segment in your network displays the Segment flyout, which contains current, and historical segment rankings crashes by milepoint, a summary of crash statistics (including number of crashes and fatal (critical) crashes, crash ratio, crash rate, crashes per mile, and location information), a summary of roadway details (including AADT, function classes, and any other roadway datapoint present in your data), and a list of recommended countermeasures for that segment.

(A Segment flyout showing the current state ranking of the segment.)

Users can open a selected segment in either Safety Analysis, Predictive Analysis, or Crash Query, depending on the applicaitons available to that user. To open a segment in the selected application, click the Open In button in the segment flyout, and select the application from the list.

(The Network Screening flyout, with the available applications that the selected segment can be opened in.)(A Segment flyout showing the current state ranking of the segment, as well as the crashes by milepoint, grouped by severity.)

Contextual Data

With photos and Google Streetview, users can explore selected segments, and even see how each segment has changed over time, all without leaving the app.

(A Segment flyout showing the current and historical state-wide ranking, as well as a link to open the selected segment in the Safety Analysis application.)

Network Screening Downloads

Network Screening - Segments supports three download options: Report (.pdf), Worksheet (.xlsx), and Geometry zip (.kmz). All of these download options are available under the Download icon, located in the top right corner of the screen.

(The Downloads dropdown, displaying the three different download options.)

Report Download

Generate a downloadable Network Screening Report which contains the network ranking, and a breakdown of each segment, including the crash rate, crash ratio, crashes per mile, fatality rate, and serious rate, and distribution of crashes along the segment grouped by severity, as well as a stacked bar chart indicating the mile point at which the crashes occurred.

(A sample Network Screening Segment Report.)

Worksheet Download

The Worksheet download allows you to download the entire ranking table of all segments that meet your screening criteria as an Excel spreadsheet file, including all the columns of data included in your ranking table. Within the application, the table will only display the top 100 segments, however, the downloaded Worksheet will include all segments that meet the filter criteria of your network screening.

(The worksheet download for a given screening, including the additional columns of AADT, BMP, EMP, Functional Classification, Number of Legs, and Length.)

Geometry Zip Download

The Geometry Zip download allows you to download a .kmz file containing the segment locations from your screening. Like the Worksheet Download, the Geometry download includes all segments that meet your filter criteria, as well as all columns of data present in your ranking table. This .kmz file can then be loaded into any mapping application.

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