5.1 A primary responsibility of highway agencies is the construction and maintenance of highway pavements in a condition (including ride quality) perceived to be satisfactory by the user community. The ability to quickly, easily, and economically acquire an objective standard numeric (rideability index) that will estimate the current level of satisfaction for lengths of pavement is desirable for determining when an acceptable level of ride quality does not exist and corrective measures are required.

5.1.1 This guide describes a procedure to produce subjectively derived, numerical ride quality ratings for each sample of a broad spectrum of highway pavement sections based on a standard numerical scale (0 to 5, described herein). These rating estimates may be considered to be closely correlated to the collective qualitative judgments of the total related highway user population.

5.1.2 The MPR data set thus obtained can be useful in testing various hypothesized deterministic functions of certain physical parameters of sections of pavement, such as the measured longitudinal profile, as estimators of the ride quality rating the user population might assign to any particular member of the total relevant inventory of highway pavement sections.

5.1.3 Objective, quantitative, easily measurable rideability index data shown to be highly correlated with MPRs are a valuable resource for monitoring the performance of highway pavement construction, maintenance, and repair operations.

1.1 This guide covers a procedure for obtaining subjective numerical ride ratings for a group of representative highway pavement sections having a broad spectrum of physical characteristics.

1.2 The intent of this guide is to describe a procedure for generating a set of comparatively scaled ride ratings, subjectively derived, for a subgroup of pavement sections having a ride quality distribution approximating the general population of highways of interest. This set will provide statistical estimates of the average subjective ride ratings which would be obtained for the same group of pavement sections if the entire population of users could be interrogated.

1.3 For the data to be a reasonable representation of the average ride quality judgments of the total highway user community for the total population of highway pavements, certain sampling theory precepts must be observed; the size of the rating panel, the selection of its members from the user community, the method of quantifying the individual judgments, as well as the selection of the sample pavement sections are all important areas to be considered.

1.4 An important use of the resulting ride quality data would be to determine the ability of various hypothesized deterministic functions of physical parameters of the pavement samples, such as measured longitudinal profile, and so forth, to provide an estimate of subjective ride quality judgments.

1.5 This guide is based on guidelines described in Appendix F of NCHRP Report 275,2 and in Appendix E of NCHRP Report 308.3

1.6 The values stated in both inch-pound and SI units are to be regarded separately as the standard. The units given in parentheses are for information only.

1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.