Surface Systems & Instruments, Inc.
Case StudyDecember 1, 2022

SSI High Speed Device Meets 98% Repeatability Reference Profiler Requirements

SSI's High Speed Reference Device Can Quickly Produce Reference Profiles For Certification Tracks

SSI has evaluated our High Speed Reference Device device on multiple certification tracks across the USA to measure repeatability. Under ASTM e950, a device qualifies as a reference device under section 13.2.8. if:

  • Distance is measured within 0.1% of the accepted value of the track
  • IRI waveband repeatability exceeding 98% for three runs (ProVal Certification Module)

The High Speed Reference Device has been shown to meet the 98% repeatability at speeds between 10-20 mph. This allows for the collection of the reference profiles to occur the same day as the certification.

Walking Speed Reference Devices

Under current operations, walking profilers collect reference data for inertial profiler certification tracks. The data is usually collected in advance of the certification day. Not collecting the reference data on the same day can allow the pavement to slightly change IRI values. These slight changes can affect the certification results of the inertial profilers when the pavement in smooth, such as pavement under 60 in/mile.

Walking profilers collect one pass of one wheelpath on the certification track in about ten minutes, plus the walk back to the starting line. Typical collection speed of walking systems is about one foot per second (1 fps). At least six passes are required to collect both wheelpaths a minimum of three times. The minimum time to collect all of the walking profiler runs time is at least an hour and fifteen minutes. It can be longer if the initial three passes do not achieve 98% repeatability and more collections are required.

SSI High Speed Reference Device

The High Speed Reference system can collect both wheelpaths at the same time at 10-20 mph. Each run will take about on minute, completing collections on the entire track in less than ten minutes.

The High Speed Reference Device is built upon our Zero-Speed Inertial Profiler Upgrade and is simple to operate. Mounting the lasers to the truck and connecting to hardware takes less than ten minutes. The collection system can be paired with a laser pointer to assist in tracking while collecting a certification track.

Daylight Visible Laser Tracker


NCAT Smooth Track in Auburn, Alabama

Mississippi Certification Track


With the SSI High Speed Reference Device:

  • Avoid daily changes in pavement profiles, collect reference profiles same day
  • Collect data in both wheelpaths
  • Collect data at 10-20 mph
  • Use a tracking laser to get better, repeatable data
  • Collect your reference track at least 6x faster

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