Download COBRA

Notes:

The installer file is large, and may take some time to download, depending on connection speed.
A Windows computer is necessary to use the tool.
COBRA 5.1 Installer (exe) - Revised June 2024

To install COBRA:

Click on the “COBRA Installer” link above to download the installer. When prompted, choose “Save” and save the file to your computer.
Locate the file “cobra5dot1.exe” on your computer and double-click to run the installer.
Follow all on-screen instructions to complete the installation.
To run COBRA, look for the “COBRA” entry in your “Start” menu.

If you have a previous installation of COBRA on your computer, uninstall it before installing the latest version of COBRA.

For detailed installation and usage instructions, reference the revised COBRA User Manual (PDF) – revised June 2024.

COBRA 5.1 includes the following updates:

Bug fixes in the code to run batch files. Batch files can be used to submit emissions data representing multiple years or scenarios so that the scenarios can run in succession without additional input from the user. This update fixed an issue where COBRA was not using the correct population and incidence input files for batch runs. This update also added an input for valuation files for batch runs, which was not included in previous versions. In addition, the format of the outputs from the batch files have been updated to match the format of the desktop model. See Appendix G of the User’s Manual for more information on running batch files for COBRA.
Updated valuation for asthma onset for 2028. The default 2028 valuation file included in COBRA had an incorrect dollar value for asthma onset from particulate matter, which was causing COBRA to underestimate the economic value of avoiding asthma onset for scenarios using the 2028 analysis year. This has been updated to the correct value of $80,211.96 per case avoided.
Updated interface for Advanced Options. This update removed the radio buttons for Model Year to select SR Matrix and Adjustments by year, which is no longer used in COBRA starting with version 5.0.

This update did not impact the Web Edition of COBRA.

For a summary of all updates to COBRA, please see the COBRA Revision History.

For more information, contact cobra@epa.gov.