Safety Analysis Intersections - App Overview

An overview of the Safety Analysis - Intersections Application.

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

The Safety Analysis - Intersections 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 - Intersections application has 6 key features: Project Overview - Area Selection, Recommendations, Applying Treatments, Project Overview - Treatment Summary, and Reports. 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.

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

You can choose from one of four options:

  • Add only the Selected Segment | This option will not add the included intersections into your analysis, and will only add the selected Segment.

    (A project, with only the Segment added to the analysis)

  • Add the selected segment and any intersections along that segment separately | This option will add the segment, as well as each intersection to your analysis.

    (A project, with the segment, and the three intersections included added to the analysis)

  • Add the selected segment and any intersections legs not along that segment as separate segments | This option will add the main segment, as well as the legs of any intersections as their own segments (no “Intersections” will appear in your analysis, only segments).

    (A project, with the segment, and the legs of all intersections added to the analysis, each as their own segment)

  • Do not add the selected segment, but add any intersections along that segment separately | This option will not add the selected segment, but will add each intersection to the analysis.

    (A project, with only the intersections added to the analysis)

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 intersection, with each crash plotted on the intersecting routes. Additionally, a breakdown of the total crashes/cost broken down by travel direction is displayed.

Safety Analysis also recommends the top three countermeasures that will mitigate the crashes for the selected intersection. 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.

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

Metrics

The Metrics tab of Safety Analysis displays a summary of all crashes along the selected intersection, 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 intersection.)

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 table of a selected intersection.)

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 intersection, with the various datasets available for selection.)

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 (agency 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 of a selected intersection, with the Intersection LightingChanging Protected-Permissive to Flashing Yellow treatment selected, with an estimated Benefit Cost ratio of 111.7687)

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 Overview page of Safety Analysis, displaying the selected intersections, all associated crashes, and the selected treatments with 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 intersection in relation to the state-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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