SYMPOSIA PAPER Published: 01 January 2003

VDOT's IRI-Based Ride Quality Specification: From Inception to 2001


In 1990, the Virginia Department of Transportation (VDOT) purchased its first South Dakota-type inertial road profiler. At that time, the profiler's primary function was to collect data required for the Federal Highway Administration's Highway Performance Monitoring System. By early 1995, however, the need to collect initial smoothness data safely, efficiently, and more accurately led VDOT to look to inertial profilers as a replacement for the California-type profilograph. In 1996, VDOT introduced a new special provision for smoothness, one that incorporated high-speed profilers and the International Roughness Index. In addition to chronicling those initial efforts, this paper discusses factors associated with achievable smoothness, as well as some deficiencies identified in the first generation of the new specification. The discussion then moves to a second generation of development, which focuses on enhancing the incentive/disincentive component of the specification, revising the smoothness targets, and reducing the pay lot size to combat excessive variability in ride quality.

Author Information

Clark, TM
Virginia Department of Transportation, Richmond, VA
McGhee, KK
Virginia Transportation Research Council, Charlottesville, VA
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Developed by Committee: D04
Pages: 68–81
DOI: 10.1520/STP10651S
ISBN-EB: 978-0-8031-5481-0
ISBN-13: 978-0-8031-3460-7