Pavement smoothness (or roughness) is used by state highway agencies for monitoring network condition as well as assessing construction quality and optimizing investments in preservation, rehabilitation, and reconstruction. States are also required to report the International Roughness Index (IRI) as an element of the federal Highway Performance Monitoring System. TRB hosted a webinar on Tuesday, March 22, 2022 that covered current practices for estimating the roughness of low-speed and urban roads as well as the challenges associated with collecting data. Presenters reviewed the calculations for determining IRI. They also covered the unique features of low-speed and urban roads that may yield inappropriate and misleading data. Presenters offered both short-term and long-term solutions.

This webinar is sponsored by the TRB Standing Technical Committee on Pavement Surface Properties and Vehicle Interaction. A 2020 TRB Webinar described methods for measuring, characterizing, and reporting roughness on urban and low-speed roads. The recording may serve as an introduction.

The slides are linked in the meeting materials. View the recorded webinar below.

Webinar agenda and presenters

1. Introduction to the issues: Robert Orthmeyer, Federal Highway Administration
2. Reducing errors at stops with error suppression algorithms: Steve Karamihas, University of Michigan Transportation Research Institute
3. Problems with quanitification: Brian Schleppi, Ohio Department of Transportation (retired)
4. Eliminating measurement errors at low speed, stops, and during braking with sensor augmentation: Steve Karamihas, University of Michigan Transportation Research Institute
5. Question and answer session: LaDonna Rowden, Illinois Department of Transportation

The first 60 minutes of the webinar will be for presentations and the final 30 minutes will be reserved for audience questions.

Learning Objectives

At the end of this webinar, participants will be able to:

1. Define urban profile measurements
2. Identify where errors can occur in urban profile measurements
3. Identify errors and methods to minimize errors of stop-and-go and equipment improvement

Professional Development Hour Information

Professional engineers (PEs) who register and attend the entire webinar as an individual will be awarded 1.5 Professional Development Hours (PDHs). TRB’s webinar program awards PDH credits only to the registered individual, and not to other members of a group that view the webinar together. To be eligible for the credits, individuals must remain signed in for the entire webinar, including for any question and answer session following the presentations.
Please check with your licensing board to ensure that TRB webinar PDHs are approved by your board.
TRB will report credits earned to the Registered Continuing Education Program (RCEP). Complaints about registered providers may be sent to RCEP, 1015 15th Street, NW, 8th Floor, Washington, D.C., 20005.

View our FAQ page for more information.