Independent Assurance Program

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Independent Assurance Program (IAP) OverviewGolden Gate Bridge

The Caltrans Independent Assurance Program (IAP) ensures that all sampling and testing of materials used in the acceptance decision is performed by qualified technicians and laboratories in conformance with Title 23 Code of Federal Regulations, Chapter I, Part 637, Subpart B (23 CFR 637B).  This section of Federal code requires each state transportation department to develop a Quality Assurance Program (QAP) that includes an acceptance program and an independent assurance program for all Federal-aid highway construction projects on the National Highway System (NHS).  Participation in the Caltrans IAP is required for laboratories and technicians providing test results that may be used in an acceptance decision.  This applies to all project-produced materials within federally funded and/or state funded Caltrans projects, or local assistance projects relying wholly or partially on federal and/or state funding.

New Independent Assurance (IA) Manual

The new Caltrans IA Manual was officially approved and signed by all mandatory stakeholders at the beginning of May 2024. The new manual provides updates to definitions, initial certification and recertification timelines, expanded details on RSP and CSP programs, and either new or updated requirements to the Inertial Profiler Certification Program (IPCP), written and practical exams, mobile labs, equipment calibrations, and document control.

Statewide Independent Assurance Database (SIAD)

The Statewide Independent Assurance Database (SIAD) is an online data repository developed by Caltrans Materials Engineering & Testing Services (METS) to provide Caltrans project personnel easy access to current qualifications of materials testing laboratories and technicians.  The SIAD is a single point access to the status of laboratory accreditations and technician certifications, and includes links to support programs and general IA staff contact information for any questions that may arise.  Website link: SIAD

IA Staff Contact Information

Independent Assurance staff are responsible for certifying technicians, accrediting laboratories, witnessing proficiency testing, reviewing local agency QAPs, and supporting IAP-related programs.  Access regional IA staff contact information at the following link: (IA Staff Regional Contacts).

Laboratory Accreditation

Obtaining Caltrans IAP accreditation will qualify a laboratory to perform project-produced highway materials testing on federal- and state-funded projects.  General rules for accreditation include the following:

  1. Accreditation is valid for 1 year and granted on a test-by-test basis for CT, AASHTO, and ASTM test methods.
  2. Accreditation applies to both testing performed in the laboratory and testing performed in the field by laboratory staff.
  3. Separate accreditation is required for temporary or mobile facilities (trailers, mobile labs, or other structures).
  4. AASHTO resource accreditation is not required except when noted in project specifications.
  5. All testing that may be used in the acceptance decision must be performed by laboratory-affiliated, certified technicians.
Laboratory accreditation requires submittal of necessary forms and a complete Caltrans Laboratory Accreditation Manual (CLAM), undergoing and passing a site assessment, maintaining and calibrating appropriate equipment, notifying the Caltrans IAP of any personnel, location or equipment changes, and participating in the Reference Sample Program (RSP).  For more information on laboratory accreditation, refer to sections below and/or the Caltrans IA Manual.

Requesting Lab Accreditations

Laboratory accreditation must be requested a minimum 30 days prior to the required accreditation date.  To request accreditation, submit the following documents to 

  1. TL-0118 Form (PDF):  Request for Caltrans Laboratory Accreditation
  2. TL-0119 Form (PDF):  Reference Sample Program Questionnaire
  3. Caltrans Laboratory Accreditation Manual (CLAM)

Upon complete submittal, IA staff will contact the laboratory within 5 business days to set an appointment for a site assessment.  Typically, the site assessment will be scheduled within 3 weeks of the initial request.  Please contact for questions regarding submittal requirements and service time expectations.

Caltrans Laboratory Accreditation Manual (CLAM)

A complete and accurate Caltrans Laboratory Accreditation Manual (CLAM) is required for laboratory accreditation.  The CLAM includes contacts, organization chart, list of personnel and qualifications, training summaries, laboratory affiliations, RSP records, list of test methods, calibrated equipment list , and nuclear storage information (if applicable).  The CLAM will be separate from other documentation such as an AASHTO re:source manual, radiation safety program, calibration reports, or quality control manual.  The CLAM may be maintained in the lab as a physical binder or may be stored electronically, but in either case, must be readily available to all laboratory staff.

The Caltrans IAP has developed straight forward guidelines to help simplify the initial CLAM assembly and annual updates.  Link to CLAM guidelines: CLAM

Site Assessment

After the CLAM has been reviewed and approved, IA staff will perform a laboratory site assessment.  The site assessment will include, but is not limited to, verification of CLAM documentation and evaluation of testing equipment and procedures. IA Staff will also review the laboratory’s quality control manual and verify the presence of a safety manual.

Link to Quality Control Manual guidelines:  QCM (under construction)

Deficiencies:  A list of deficiencies, if noted, will be summarized immediately following the site assessment and provided to the laboratory manager.  A formal deficiencies report will be provided within 5 business days.  General rules regarding deficiencies:

  1. The laboratory must provide satisfactory evidence that all deficiencies have been corrected before accreditation can be granted.
  2. The laboratory will be suspended for test methods affected by deficiencies that cannot be immediately corrected.
  3. IA staff may provide conditional accreditation for up to 90 days for test methods and related equipment unaffected by the deficiencies report.

Upon successful completion of the site assessment, the laboratory will be provided a 1-year accreditation and be updated in the SIAD.

Maintenance and Calibration

All equipment must be maintained in good working order for the duration of the accreditation.  All equipment requiring calibration must be calibrated on the required interval and must have an appropriate calibration decal affixed to the equipment.  Equipment with expired calibration shall not be used for testing.  Caltrans IAP has developed general guidelines and individual equipment calibration forms to assist laboratories with calibration requirements.

Link to calibration guidelines:  Calibration Guidelines  (under construction)

Reference Sample Program (RSP)

The Reference Sample Program evaluates laboratory equipment and practices, tester competence and the repeatability of test results.  Each year, the RSP will identify one or more test methods for evaluation and will contact respective accredited laboratories to inform them of the impending sample distribution.  Each laboratory is required to participate in RSP testing in any test method in which the laboratory maintains Caltrans accreditation.  If the laboratory does not maintain accreditation in a test method identified for RSP evaluation, then the laboratory is exempt from the RSP requirement for that respective evaluation.  For more information, please visit the RSP website:  Reference Sample Program.

Personnel, Location, and Equipment Changes

Per the Caltrans IA Manual, a laboratory must notify IAP Staff of personnel, location, or equipment changes within 10 business days.  If your laboratory has a reportable change that will affect qualified test methods or accreditation status, please email or to your regional IA representative (IA Staff Regional Contacts) with “Notification of Laboratory Status Change” in the subject line.

Mobile Laboratories

Any time a mobile laboratory is relocated, all equipment requiring calibration must be recalibrated.  The mobile laboratory should maintain a calibration log which identifies the relocation date, equipment subject to calibration, and the respective calibration dates related to the relocation.  The mobile lab must have reasonable access to appropriate calibration equipment such as NIST traceable thermometer, calibrated weights, a NIST load cell, etc.

Truck- or van-mounted laboratories that move regularly with a project, such as mobile labs used for rapid-set concrete testing, should have appropriate devices to calibrate testing equipment on at least a weekly basis.

Tester Certification

Certification qualifies a technician to perform project-produced highway materials testing on Federal- and State-funded projects.  Technician certification is typically performed at the lab to which the technician is associated, however with appropriate notification, an alternate laboratory may also be used.  The associated or alternate laboratory must have current accreditation in the test methods to be certified.

Requesting Tester Certification

Technician certification must be requested a minimum 30 days prior to the required certification date.  To request certification, submit the following documents to

  1. TL-0120 Form (PDF):  Request for Technician Certification
  2. TL-0121 Form (PDF):  Technician Training and Evaluation Record
  3. TL-0122 Form (PDF):  Employer Affidavit of Testing Proficiency

Upon complete submittal, IA staff will contact the laboratory manager and technician within 5 business days to set an appointment for written and practical exams.  Typically, the testing will be scheduled within 3 weeks of the initial request.  Upon successful completion of exams, the tester will be provided a certification document and their profile will be updated in the SIAD.  Certification term length is provided as follows:

  • Initial certification to a test method:  1 year
  • Recertification to a test method:  2 years

Note 1:  If a certification has been expired for more than 1 year, it will not be considered for recertification and will reset to initial certification.
Note 2:  If a certification has been expired for more than 45 days, but less than 1 year, then written exam completion will be required for recertification.

Please contact for questions regarding submittal requirements and service time expectations.

Corroboration Sample Program (CSP)

The Corroboration Sample Program (CSP) verifies technician proficiency through witnessed testing of control samples.  The technician will need to identify appropriate equipment, demonstrate proper test method procedures and express knowledge of requirements.  Upon completion of the testing, the technician will complete and submit a reporting form to the CSP.  The technician’s results will be graded among the following options: good, fair, or poor.  If a poor result is reported, the technician will be required to re-perform the test on another control sample.  For more information on the program, please visit the CSP website.

Joint Training and Certification Program (JTCP)

The Joint Training and Certification Program (JTCP) is a mandatory training program that was established in 2017 by a Caltrans-Industry partnership.  The JTCP makes the certification process more effective and efficient with the goal of providing consistent, reliable, and quality highway construction materials testing on all Caltrans projects.   The JTCP offers training and certification in several multi-test method modules including Soils & Aggregates, Hot Mix Asphalt, and Portland Cement Concrete.  Technicians needing certification in test methods included in the JTCP must enroll in and complete the related training module.

For more information on JTCP, please visit our JTCP website.

To enroll in JTCP, visit the CSULB website:  CSULB | Caltrans - Joint Training & Certification Program

Inertial Profiler Certification Program (IPCP)

The Inertial Profiler Certification Program (IPCP) is an alternative certification program that evaluates technician proficiency at performing California Test 387 – Operation, Calibration and Operator Certification of Inertial Profilers.   Inertial Profilers are used to measure pavement smoothness based on an inertial reference system that is mounted on a host vehicle.  Both the operator and equipment are checked in the certification process.  For more information on this program, please visit the IPCP website.

Technician Training Guides

Caltrans IAP has begun assembling Technician Training Guides to assist with technician development.  Our current available training guides include:

  • CT 125 – Appendix A:  Sampling Aggregates, Soil, and Lime
  • CT 125 – Appendix B:  Sampling Hot Mix Asphalt (HMA)

To request a training guide, please email with “Training guide request” in the subject line.