Safety Analysis Segments - App Overview

An overview of the Safety Analysis - Segments Application.

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

The Safety Analysis application helps users produce Highway Safety Manual (HSM) powered benefit-cost calculations in seconds. Safety Analysis helps organizations calculate how each dollar spent on countermeasures affects the specified crashes, and helps allocate safety funds with maximum effectiveness. The Safety Analysis application has 6 key features: Project Overview - Area Selection, Recommendations, Applying Treatments, Project Overview - Treatment Summary, Reports, and Economic Appraisal. Each feature is discussed in more detail below.


​Project Overview - Area Selection

The Project Overview screen summarizes the locations (segments and intersections) associated with the Safety Analysis project. When creating a new project, users can define a segment or intersection by clicking the Add Segment or Add Intersection buttons at the top of the screen.

This will open the segment or intersection selection window. From here the users can easily select the desired intersection from the map, or define the Route, as well as the beginning and ending milepoints for the project. Once the Route is selected, the user can either click the beginning and ending milepoints on the map, or define the values in the appropriate filed above the map.

(The Route Selection screen)

When selecting a Segment that contains any intersections, you will be prompted with several options on how to handle the included intersections. These intersection handling options are discussed in more detail in the Safety Analysis - Intersections App Overview article.

(The Include Intersections popup, with four different intersection handling options.)

Once added, users can customize the name of the selected segment or intersection. And add additional segments/intersections as desired by following the same steps above.

(A project with both a segment, and an intersection included)

Recommendations

The recommendations section of Safety Analysis displays a map of the selected road segment, with each crash plotted on the segment. Additionally, a breakdown of the total crashes/cost per milepoint is displayed.

Safety Analysis also recommends the top three countermeasures that will mitigate the crashes for the selected segment. These are visualized with a Venn diagram illustrating the top three countermeasures, and the benefits from the treatments within these countermeasures. Numetric’s Safety Analysis application automatically generates these countermeasure recommendations based on logic applied to the crash attributes in the associated crashes (Note: Numetric will work with the agency during the implementation process to configure countermeasure logic). 

(The Safety Analysis Recommendations page, with the crashes, plotted on the map, a bar graph illustrating the crashes per milepoint, and the recommendations for the selected segment.)

Metrics

The Metrics tab of Safety Analysis displays a summary of all crashes along the selected route, a summary of total and fatal crashes, and a detailed breakdown of the following data categories: types of crashes, severity of crashes, day of week, first harmful event, manner of collision, light conditions, road surface conditions, weather conditions, and any other key data points identified.

(The Metrics tab of a selected route)

Additionally, if your agency has multiple datasets connected, you can select Crash, People, or Vehicle level metrics for display.

(The Manage Metrics section of a selected route, with the various datasets available for selection.)

Raw Table

The Raw Table Tab displays all available data that meet the current search criteria for the query in a customizable, downloadable table.

Users can add and remove any columns of data from the table, and sort by any available column to display the data exactly how they want.

(The Raw Table tab of a selected route.)

Clicking on any row in the table will open the Crash Flyout for the selected crash. From the Crash Flyout, users can review relevant crash information and remove the selected crash from the treatment if desired.

By clicking the Exclude Crash button in the Crash Flyout, the crash will be filtered out of this specific treatment.

(The Exclude Crash window, with Inaccurate Crash Location selected as the exclusion reason.)

Any time a crash is excluded from a treatment, a crash exclusion message will appear on the right side of the screen, above the data sidebar. Excluded crashes are only excluded from the current treatment. If the treatment is saved, all crash exclusions will be saved within that treatment only. A crash can be easily re-included in the treatment by clicking the Include button again from the crash flyout, checking the box next to the crash in the Raw Table tab, or from within the crash exclusion notification above the metrics sidebar.

(The crash exclusion notification message, displayed above the raw table tab, indicating one crash has been excluded from the treatment).

Note that crashes can also be excluded by unchecking the selected crash from the Raw Table tab.

Applying Treatments

The treatment application window allows a user to apply a treatment to a section of the project. When the user provides the cost of the treatment and the maintenance cost over the lifetime of the treatment (if enabled for your agency), Numetric will calculate the Benefit Cost ratio as well as provide annual cost savings, and annual cost reduction calculations. Users are also able to modify default CMFs (City default CMFs will be incorporated into the application), and service life of the treatment. Any changes from the defaults will be noted in the application, as well as in the Safety Report.

(The treatment selection window, with the Curb Extension with Parking Restriction treatment selected, displaying an estimated Benefit Cost ratio of 4.389.47)

Project Overview - Treatment Summary

The Project Overview provides quick insight into the proposed work for a project. Project Overview displays the selected segments/intersections and treatments or improvements that have been identified for each selected segment or intersection. The overview also displays the Benefit construction costs, maintenance costs, and Benefit Cost ratio for each treatment.

Additionally, the project overview displays the total benefit, total project cost, and total Benefit Cost ratio for the entire project.

(The Project Overview displaying the selected route, and two selected treatments with their location, benefit, and benefit cost ratio displayed.)

Report

Safety Analysis comes with a pre-built Safety Report, which can be used to export the results of your Safety Analysis in an easy-to-share PDF, or printed report. The Safety Report contains all of the data displayed in the Overview and Recommendations section of the Safety Analysis application. Additionally, the Safety Report also includes the proportion of each crash type for the selected segment in relation to the city-wide average. This can be used to determine if there is an excess proportion of a specific crash type occurring within the selected segment.

Economic Appraisal

Safety Analysis makes it easy to conduct an economic appraisal of a series of Safety Analysis projects to determine the most efficient expenditure of safety resources. Users can utilize the Economic Appraisal feature of Safety Analysis to identify which projects can be undertaken for the greatest return on a given budget. Users can simply select the projects they would like to choose from, enter a budget amount, and Safety Analysis will compile a list of recommended projects that will use the identified budget for the greatest return.

(An Economic Appraisal showing the 5 projects recommended for the budget of $1,500,000 and an estimated benefit of $13,997,398)

For more information on how to generate an economic appraisal, see the Safety Analysis - How to Generate an Economic Appraisal article.

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