SCANNER Quality Assurance and Accreditation

To provide local authorities, and the Department for Transport, with confidence that SCANNER datasets are consistent, and suitable for national performance monitoring and to support local maintenance operations, a quality assurance procedure was developed and fully incorporated into the SCANNER specification. The specification defined quality assurance requirements including accreditation tests for all survey machines, checks on machine operation through a procedure of weekly and daily tests carried out by the contractor, and external audits in the form of repeat surveys undertaken both by the survey contractor and an independent auditor. The data collected by SCANNER vehicles is often processed by accredited UKPMS systems (the most recent test being the current Annual Health Check).

Since the end of the previous DfT contract in September 2010 SCANNER accreditation, Quality Assurance and Audit has been provided as a commercial service by TRL Limited.  Further information about these changes is provided in a letter from the DfT to local authorities dated 6th June 2011.

Accredited Survey Vehicles       Vehicle Accreditation Certificates       Accreditation Testing       Quality Assurance

Current Accredited SCANNER Survey Vehicles

Accreditation Testing Process

Before a survey vehicle can be used to carry out a SCANNER survey, it must have a valid accreditation certificate, which is obtained by passing a stringent set of annual accreditation tests (described in Volume 5 of the SCANNER Specification).  It must be operated with a defined quality assurance procedure (described in Volume 4 of the SCANNER Specification) and supervised by an independent Auditor (currently TRL). 

The accreditation testing is carried out at a number of different levels:

• The site tests compare the individual parameters measured by the survey equipment against those measured by a reference method.
• The network tests assess the operational capabilities of the survey equipment (and survey crews) on one or more routes located on the public road network.
• The data output from the equipment is also checked to ensure that it complies with all the requirements for loading into a UKPMS accredited system.

If the equipment fails to achieve the required levels of accuracy in the measurement of individual parameters, the machine developer or survey contractor may seek to resolve this issue by enhancing the performance of the equipment and re-presenting for accreditation testing.

On successful completion of the tests a SCANNER Accreditation Certificate is issued by the Independent Auditor. This is valid for a twelve month period and to ensure continuous accreditation the vehicle may commence re-accreditation testing 10 months after the certificate started. The Auditor has the power to revoke (at any time) a SCANNER accreditation certificate if it believes the quality of the SCANNER data has been compromised.

Quality Assurance Process

In order to provide comprehensive quality assurance for SCANNER accredited surveys, QA is provided by a combination of 'first party' QA, operated by the contractor and 'third party' Audit, provided by an independent auditor.

The contractor provides and operates an effective and documented Quality Assurance regime covering all aspects of the SCANNER accredited surveys, including:

• vehicle operation and maintenance
• driver and operative training and instruction
• survey operation and record keeping
• data recording, processing, and analysis
• delivery of survey results.

The Auditor monitors the contractor’s internal QA processes to ensure these are of suitable quality and are correctly implemented. The auditor also undertakes a QA programme of repeat surveys to ensure the collected SCANNER data is of the best quality. The repeat survey programme is based on a selective sample basis concentrating on the individual survey vehicles rather than individual Highway Authorities or road networks. The programme consists of contractor repeat surveys and auditor repeat surveys.

Contractor's repeat surveys

These demonstrate the repeatability of the SCANNER survey equipment. The procedures for these tests are:

• The contractor repeats a SCANNER survey with the survey vehicle.
• The location and timescales of the repeat surveys are to be agreed with the auditor before completion.
• These are carried out at approximately monthly intervals and are approximately 5-10km in length.

Both sets of data are delivered to the auditor for assessment against the requirements in the specification. The auditor will compare the data sets to see if the assessment has been successful and if any further action is required.

Auditor's repeat surveys

These demonstrate the reproducibility of the SCANNER survey equipment. The procedures for these tests are:

• The auditor selects and repeats a SCANNER survey using an independent survey vehicle.
• Each repeat survey will have an individual length of no more than 10km.
• The contractor supplies the SCANNER data from this survey to the auditor.

The auditor will compare the two data sets to see if the assessment has been successful and if any further action is required.

Page last updated on: 14 May 2013