New Jersey

Department of Transportation

Standard Specifications

for Road and Bridge Construction


NJDOT R-1 Operating Inertial Profiler Systems
for Evaluating Pavement Profiles

  1. Scope. This test method describes the procedure for operating, verifying the calibration of an ASTM E 950 Class 1 Inertial Profiler System (IPS) and testing riding surface for pavement profiles evaluation.

  2. Apparatus. Use an IPS that meets the requirements of AASHTO M 328 and ASTM E 950, Class 1 and the following:

    1. Certify the IPS according to AASHTO R 56 at least every 2 years. If a system component is replaced, re-certify the system. Perform the certification at a site approved by the Department.
    2. The data system provides the raw profile data in an ASCII format acceptable to the Department.
    3. The computer program uses a high-pass filter set at 300 feet and reads an ASCII or text file for computing the International Roughness Index (IRI) in inches per mile.
    4. The current version of ROADRUF, ProVal, or other Department approved pavement profile analysis software is used to compute the IRI.

  3. Procedure. Perform the following steps:

    1. Operate the IPS according to AASHTO R 57 and ASTM E 950.
    2. On a daily basis before data collection, check the equipment and operating system for operational stability and calibration. Perform necessary calibration procedures according to equipment manufacturer’s procedures and applicable standards. Operators shall maintain a log documenting the calibration history.
    3. Ensure that the operators of the IPS have completed a profile training course, such as NHI Course 131100, have been trained specifically on the IPS they will be operating, and are proficient in the operation of the IPS.
    4. Make provisions to automatically start and stop the IPS recording at the beginning and end of testing.
    5. Ensure retroreflective traffic striping tape or other approved mechanism is placed at the beginning and end of each direction of travel for automatically triggering the start and stop of profile measurements.
    6. Collect at least 0.05-mile of data before the area to be tested to allow the system to stabilize before profile measurements are obtained. Collect data in a continuous run through the length to be tested. If the run is interrupted, discard the results and re-run the length.
    7. Test the full extent of each wheel path of each lane in the longitudinal direction of travel. The wheel path is defined as being located approximately 3 feet on each side of the centerline of the lane and extending for the full length of the lane. Lanes are defined by striping.
    8. Run three tests each wheel path and report average of three runs each wheel path.
    9. Exclude locations where the traffic striping includes turn lanes that cause the through traffic lane to cross over a longitudinally paved joint, ramps, and lanes such as acceleration and deceleration lanes of less than 1,000 feet of continuous through treatment.
    10. Report single IRI value average of 3 runs unless otherwise directed.  The single IRI value shall be each 0.01 mile length for each lane, ramp, and shoulder and 0.005 mile for each overlaid bridge structure.

Last Document Correction:
May 11, 2012