PRBE Version 73.0.2

Probabilistic Risk-Based Estimating (PRBE) for

Highway Project Cost and Schedule

- Improving the reliability of project estimates one analysis at a time -

Tech Support Contact: Michael.Smith935@gmail.com Cell Ph: 678-702-7769

Use the upper right drop-down "v" to navigate the website.

Update 4/23/2026:

The PRBE spreadsheet has been significantly enhanced in version 73.0.1 and is now available free of charge. Performance has improved by nearly 80%, and the program no longer requires DLL files, making it much easier to use and more portable.

Also please be aware that I am implementing my own stand alone version of PRBE named CASTR. See website below:

https://michaelsmith935-ux.github.io/CASTR-website/

CASTR stands for Cost and Schedule Total Risk and implements the PRBE framework as a standalone desktop application. Feel free to download a trial version and test it out. Some great additions include extreme speed (20k iterations done in seconds), an integrated AASHTO recommended contingency range to assess implied contingency at the phase-segment level, a Risk Triage view with risk scoring to prioritize and seed crtical risks, a Pre/Post Risk mitigation analysis, risk picker library, extensive built in-app help and FAQs, risk register "snapshot" to save database during risk workshops, and much more.

If you have any questions, please feel free to contact me.

Thank you,

Michael Smith

michael.smith935@gmail.com

About PRBE Application Tool (Duration 1:53)

The PRBE Application Tool is a user-friendly software designed for creating detailed, confidence-based cost and schedule estimates for highway infrastructure projects. This tool is compatible with Microsoft Excel 2016 and newer versions and can be installed easily without needing administrative privileges. It is available for free download and use.

Key features of the tool include:

Integrated analysis of both cost and schedule.

Monte Carlo simulation for comprehensive risk assessment.
Analysis capabilities for base variability, market conditions, and specific project-related risks.
Features for incorporating risk impact distributions, probabilities, dependencies, and their correlations with other risks.
Software administrative rights are not required to install and use.

The tool's interface is designed for ease of use, allowing users to seamlessly navigate and conduct advanced cost and schedule risk analyses. It enables users to establish a probability-based estimate of project cost and schedule; and evaluate contributions to contingency, market condition effects, specific risk impacts, and different inflation scenarios. Additionally, the tool provides various graphical representations like distribution curves, tornado graphs, risk rankings, and extreme tail analysis, aiding in the clear understanding of simulation results.

The underlying PRBE concepts and methodology are supported by free online training provided by the Federal Highway Administration, accessible here: https://bit.ly/NHI_134205.

Download the Free PRBE Application Tool ...

Download Quick Install Guide
Download PRBE Zipped Installation File

To support the PRBE Application Tool, a series of instructional Videos have been created and are available at the navigation links below.

Navigate to Application Tool Instructional Videos
Navigate to PRBE Examples
Navigate to Virtual Recording on Concepts & Process

About this site ...

This website is the creation of Michael Smith, who initiated it after retiring from the Federal Highway Administration in December 2023. Throughout most of his 32-year career, Michael devoted himself to advancing quantitative risk assessment at a national level. This site is his way of continuing to contribute to the field. If you find the information and resources here beneficial, it validates the time and effort Michael invested into this project. Should you encounter any technical difficulties using the PRBE tool, please don't hesitate to get in touch with Michael.

Michael.Smith935@gmail.com Cell Ph: 678-702-7769