Description

This document provides standardized technical guidelines and operational norms for measuring road surface roughness across national and state highway networks in India. Surface roughness, quantified by the International Roughness Index (IRI), is the single most critical indicator of pavement functional condition, directly affecting vehicle operating costs, riding comfort, and fuel efficiency. The guidelines outline standard procedures for field calibration, validation, and operation of various roughness measuring equipment, including Class 1 precision laser profilometers, Class 2 response-type road roughness meters (RTRRMs), and automated road inspection vehicles. Detailed protocols are established for pre-test site selection, speed maintenance during survey runs, temperature correction, and data verification to ensure consistency and repeatability. Furthermore, the document defines acceptable threshold limits and serviceability norms for different road classifications (Expressways, National Highways, State Highways, and Rural Roads) and surfacing types (Asphalt Concrete, Thin Bituminous Surfacing, and Cement Concrete). Serviceability limits for newly constructed roads and maintenance intervention triggers are clearly defined. The guidelines serve as an authoritative reference manual for highway contractors, supervising engineers, and public works departments to enforce quality assurance, monitor performance-based contracts, and prioritize resurfacing programs.