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The contents of this report reflect the views of the author(s), who is responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the Virginia Department of Transportation, the Commonwealth Transportation Board, or the Federal Highway Administration. This report does not constitute a standard, specification, or regulation. Any inclusion of manufacturer names, trade names, or trademarks is for identification purposes only and is not to be considered an endorsement.


Factors Affecting Maintenance Overlay Ride Quality: 1996 Rideability Status
Kevin K. McGhee
Kevin K. McGhee
Year: 1997
VTRC No.: 98-IR1
Abstract: In early 1996, the Virginia Transportation Research Council initiated a formal analysis of the factors affecting overlay ride quality. As part of that effort, a statewide, multi-year survey of the ride quality for both new overlays and pavement awaiting overlays was initiated. Also during the 1996 construction season, the Virginia Department of Transportation began to pilot a special provision for pavement smoothness. This new provision is somewhat unique in that it replaces the California type Profilograph with a South Dakota style road profiler. Correspondingly, ride quality targets and pay adjustments, previously established in terms of the Profile Index (PI), are expressed in terms of the International Roughness Index (IRI). This interim report presents a summary of the ride quality of Virginia's maintenance overlays as observed for the 1996 construction season. The information covers nearly 1,600 lane-kilometers (990 miles) of overlay in 61 counties of eight construction districts. The findings suggest that the achievable smoothness of an overlay is highly influenced by functional classification. For example, the average smoothness of overlays on interstates was well below the specified target while most overlays on two-lane primary highways would have fallen just short. In general, current targets for ride quality (in terms of IRI) appear to be well within the capabilities of most of Virginia's paving contractors. Preliminary results of the pilot study indicate that the presence of a smoothness specification can have a distinctly positive influence on overlay ride quality.