Meaning
High precision measurement protocols utilize light based sensors to capture the longitudinal and transverse elevation changes of a pavement surface. A laser profileograph survey provides a continuous record of road smoothness that is used to calculate international roughness index values and identify localized bumps. The survey concludes once the entire specified section has been scanned and the raw data has been filtered for noise.
Instrumentation Performance
Mobile platforms equipped with non contact sensors travel at highway speeds to collect data without requiring lane closures. During a laser profileograph survey, the device emits beams that reflect off the surface and return to a receiver to determine the distance from the vehicle to the ground. This method replaces older mechanical systems that were slower and more prone to operator error.
Data Quality
Accelerometers on the vehicle compensate for the bouncing of the suspension to ensure the measurements match the actual road geometry. If a laser profileograph survey is conducted during heavy rain or on very dusty surfaces, the readings can be distorted by water or debris. Calibration against a known reference ensures that the vertical resolution remains within sub millimeter tolerances.
Acceptance Standard
Construction contracts use these results to determine if a newly paved section meets the required smoothness levels. A laser profileograph survey identifies areas that require diamond grinding or additional overlays to reach the target quality marks. Payments to contractors are often tied to the statistical distribution of the profile measurements.
This process provides an objective record that protects the owner from accepting substandard work while allowing the contractor to verify their performance immediately. High speed data acquisition allows for the rapid assessment of hundreds of lane miles within a single work week.
