California Department of Transportation

Pavement Profile Smoothness

ASTM defined roughness as: The deviations of a surface from a true planar surface with characteristic dimensions that affect a vehicle ride quality.

Smooth Road

Smoothness Matters

National surveys of road users list smooth pavement as a top highway characteristic. Rough or uneven pavement adversely affects driver safety, fuel efficiency, ride quality, vehicle wear-and-tear, and pavement durability.

Smoothness Specifications

Inertial Profiler Certification Program

File Sharing System

Smoothness Pilot Projects

  • Pilot Incentive/Disincentive Specifications
    • Criteria to Use Specification
    • How to Obtain Approval
    • Letter from Chief Deputy
    • Projects Already Approved to Pilot

Measuring Smoothness

  • International Roughness Index
  • National Rankings
  • How Texture Relates
  • Measuring Devices

Smoothness Publications and Presentations


Related Websites


Please forward any questions/comments/suggestions to Waheed Maroof ( Last updated 2/5/2018.