High speed, longitudinal road profiling

Road surface profiling is an important part of highway and pavement engineering. Systems have been developed to collect real-time continuous highway-speed measurements of longitudinal profiles of road surfaces. From this data, engineers calculate International Roughness Index (IRI) or Ride Number (RN). Both of these numbers are expressions for the roughness (and therefore ride comfort) of a road surface.

Road profiling systems incorporate non-contact laser sensors to measure to the road surface and accelerometers to compensate for the effects of the vehicles movement. There are specialized road profiling systems for transverse profile, rut depth, macro texture and other shape characteristics.

Profiling has become a crucial practice for transportation departments throughout the world. Road builders, contractors and even US State DOT's (Departments of Transportation) are responsible for gathering statistical information on road surfaces including the longitudinal profile, mactrotextures, microtextures and roughness to determine coefficients of friction. The measuring tasks are especially challenging for most lasers because road surfaces present many dynamically-changing targets including tarmac, concrete, yellow striping, white striping, etc. Acuity developed special lasers to maintain a consistent sampling rate over varying targets. To learn more about the field of road profiling, you may download the Acuity white paper on Road Profiling ( PDF 291KB) or download the Little Book of Road Profiling by UMTRI.

Acuity has worked with developers of road profiling equipment to produce versions of the AR700 laser distance gauge for use as primary sensors for inertial profilers meeting ASTM Class 1 standards. The result is an AR700 with optics, electronics, and signal processing algorithms specifically for road profiling. Optics, electronics, and signal processing algorithms have been optimized for profiling. The AR700's 9.4 KHz sampling speed and low-noise digital output makes it the standard for road profiling applications. The result is an extremely accurate, cost-effective sensor for all surface types, vehicle speeds, and vibration, sunlight, and temperature conditions encountered in profilometry applications.

Acuity has deployed over 300 laser sensors for road profiling worldwide.