In May 2014 it was agreed to form a new group to investigate and drive continued improvements to SCANNER, The group consists of members from local Authorities, Scotland, SCANNER contractor and the Auditor, and is called the SCANNER Development Group.

The minutes and agendas of the SCANNER Development Group meetings can be found here (link to follow shortly).

Enquiries about the SCANNER Development Group should be addressed to:
Alex Wright
TRL Limited
Crowthorne House
Nine Mile Ride
Wokingham
Berkshire
RG40 3GA
Email: mwright@trl.co.uk
Tel: 01344 770265
Fax: 01344 770356

SCANNER surveys are commissioned by local authorities. The minimum requirements for surveying are those needed to cover the authorities’ reporting requirements for Best Value Performance Indicators in England; Statutory Performance Indicators in Scotland; and National Strategic Indicators in Wales, but highway authorities are encouraged to consider whether further surveys would be useful for the management of their road networks

There are currently two companies operating SCANNER-accredited machines: WDM Ltd, and Ginger-LEHMANN.

Advice to local authorities on procuring surveys is detailed in the SCANNER specification Volume 2: SCANNER surveys for Local Roads User Guide and Specification Volume 2 Advice to Local Authorities: Procuring SCANNER surveys 2011

The research has been completed. The research reports are available below (as featured in Transportation Professional (TP) in July/August 2017).

Research reports about the development of SCANNER are now available on the UKRLG website - see below - following the publication of the updated piece in the May edition of TP.

SCANNER surveys were introduced in 2009 to provide network-wide condition assessment of the local A, B and minor road networks using survey vehicles that travel at traffic speed. Laser sensors measure the shape of the road surface and digital cameras capture images of the surface.

In 2014 there were three key areas where enhancements or modifications to SCANNER were required based on views from local authorities, software developers, survey contractors and the SCANNER auditor. These were for consistency, SCANNER condition parameters, and on the appropriateness of the
SCANNER road condition index.

The Scottish Road Research Board, in collaboration with the UK Roads Board, commissioned work to investigate and develop SCANNER surveys in the three key areas identified, separated into three tasks.

Results of the work are now available as TRL published project reports PPR816 and PPR817, for Tasks 1&2 (Consistency, SCANNER Condition Parameters) and Task 3 (Appropriateness of the SCANNER RCI) respectively. An Executive Summary is also available.

Development of SCANNER and UKPMS:
Task 1 - Consistency of SCANNER data and
Task 2 - SCANNER Condition Parameters

Development of SCANNER and UKPMS:
Task 1 - Consistency of SCANNER data
Task 2 - SCANNER Condition Parameters
Task 3 - Appropriateness of the SCANNER RCI

Development of SCANNER and UKPMS:
Task 3 - Appropriateness of the SCANNER
RCI

What is quality scoring?

At the start of the 2014/15 survey year it was proposed that a quality score system be introduced for SCANNER to provide an objective measure of the level to which contractors are delivering the requirements of the SCANNER Quality Assurance process defined in volume 4 of the SCANNER specification SCANNER surveys for Local Roads User Guide and Specification Volume 4: Technical Requirements for SCANNER Survey Data and Quality Assurance 2011

It should be noted that the Quality Score is solely a measurement of the level to which the SCANNER contractor has met the delivery and monitoring requirements of the QA process:

The SCANNER quality score does not reflect or indicate the ability of a contractor to deliver SCANNER surveys.
The SCANNER quality score does not provide an assessment of the accuracy or consistency of the data provided by any particular contractor.
The SCANNER quality score does reflect the current level to which a contractor meets the formal QA process requirements of SCANNER.
The quality score process was run on a trial basis during 2014/15 survey to obtain an understanding of the behaviour of the measure, and is being published to stakeholders from the start of the 2015/16 survey year.

What are the current SCANNER quality scores?

The table below shows the quality score achieved by the current survey contractors operating accredited SCANNER devices for the current and previous survey years. 

2021/22 Survey Results

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 defines quality assurance requirements including accreditation tests for all survey machines,

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 DfT letter on SCANNER QA arrangements

SCANNER quality assurance process

In order to provide comprehensive quality assurance for SCANNER accredited surveys an accredited SCANNER machine must be operated with a defined quality assurance procedure as defined in the SCANNER specification Volume 4 SCANNER surveys for Local Roads User Guide and Specification Volume 4: Technical Requirements for SCANNER Survey Data and Quality Assurance 2011 and supervised by an independent Auditor (currently TRL). QA is provided by a combination of 'first party' QA, operated by the contractor and 'third party' Audit, provided by an independent auditor.

For information on Contractor's QA click here

For information on Auditor's QA click here.

Enquiries about SCANNER quality assurance process should be addressed to either Patrick Werro or Christopher Torkington of TRL, or alternatively email scanner@trl.co.uk

TRL Crowthorne House Nine Mile Ride Wokingham Berkshire RG40 3GA Tel: 01344 773131 Fax: 01344 770356

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,

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 DfT letter on SCANNER QA arrangements

SCANNER 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 detailed in the SCANNER specification Volume 5 (LINK). It must also be operated with a defined quality assurance procedure as defined in the SCANNER specification Volume 4 SCANNER surveys for Local Roads User Guide and Specification Volume 4: Technical Requirements for SCANNER Survey Data and Quality Assurance 2011 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.

Current accredited SCANNER survey vehicles

There are currently 13 accredited SCANNER machines operated by three companies PTS Ltd, WDM Ltd, and Ginger-Lehmann (Yotta Surveying were acquired by Ginger-Lehmann in 2018. The survey devices are unchanged). Those devices where the certificate is currently expired are undergoing the reaccreditation process (except Tempest1 which was granted a short certificate extension until 6th June 2021 and has now retired). 

Information on SCANNER devices including the latest accreditation certificates are listed in the table below. Earlier certificates are available upon request to TRL. 

Enquiries about SCANNER accreditation process should be addressed to either Patrick Werro or Christopher Torkington of TRL, or alternatively, email scanner@trl.co.uk

TRL Crowthorne House Nine Mile Ride Wokingham Berkshire RG40 3GA Tel: 01344 773131

The SCANNER specification consists of five volumes and contains all the information required for all stages of SCANNER surveys.

Volume 1 provides a brief summary of the requirements for SCANNER surveys

Volume 2 contains advice to Local Authorities about the procuring SCANNER surveys under the SCANNER Specification and is to be read in conjunction with the other documents.

Volume 3, Using SCANNER data, explains the background to SCANNER Surveys and gives further guidance on the interpretation of processed SCANNER data.

Volume 4, Technical Requirements - SCANNER Survey Data and Quality Assurance, defines the technical requirements for the services to be provided by the survey contractor, including the Survey Data and the requirements for Quality Assurance procedures to ensure the Services are consistent and reliable.

Volume 5, Technical requirements for SCANNER Survey Parameters and Accreditation defines the technical requirements for the parameters provided by the machine developer, including acceptance and consistency testing and accreditation.

For the latest specification documents (see more details below):

SCANNER survey for Local Roads User Guide and Specification Volume User Guide and Specification Volume 1 Introduction to SCANNER surveys 2011

SCANNER surveys for Local Roads User Guide and Specification Volume 2 Advice to Local Authorities: Procuring SCANNER surveys 2011

SCANNER surveys for Local Roads User Guide and Specification Volume 3 Advice to Local Authorities: USING SCANNER survey results 2011

SCANNER surveys for Local Roads User Guide and Specification Volume 4: Technical Requirements for SCANNER Survey Data and Quality Assurance 2011

SCANNER surveys for Local Roads User Guide and Specification Volume 5 Technical Requirements for SCANNER Survey Parameters and Accreditation 2011

Enquiries about the SCANNER specification should be addressed to either Alex Wright, Patrick Werro, or Chris Torkington of TRL, or alternatively email scanner@trl.co.uk.

TRL
Crowthorne House
Nine Mile Ride
Wokingham
Berkshire
RG40 3GA

In 2011 TRL made further revisions to volume 1 to 4 of the SCANNER specification to incorporate feedback on the new QA process from the SCANNER contractors.

Volume 1 provides a brief summary of the requirements for SCANNER surveys and is intended to be read as a free-standing document, as well as providing an overview of the other four volumes. SCANNER Surveys for Local Roads Specification Volume 1 Advice to Local Authorities is available in the table below.

Volume 2 contains advice to Local Authorities about the procuring SCANNER surveys under the SCANNER Specification and is to be read in conjunction with the other documents. It includes advice on preparing contact documents, inviting bids, assessing tenders, network referencing and managing contracts. It includes a model contact document as an annex. SCANNER Surveys for Local Roads Specification Volume 2 Advice to Local Authorities is available in the table below.

Volume 3, Using SCANNER data, explains the background to SCANNER Surveys and gives further guidance on the interpretation of processed SCANNER data. It contains advice on receiving and using SCANNER data, interpreting the results for local asset management and maintenance, producing and understanding performance indicators, and reporting NRMCS results. SCANNER Surveys for Local Roads Specification Volume 3 Advice to Local Authorities is available in the table below.

Volume 4, Technical Requirements - SCANNER Survey Data and Quality Assurance, defines the technical requirements for the services to be provided by the survey contractor, including the Survey Data and the requirements for Quality Assurance procedures to ensure the Services are consistent and reliable. It also includes the specifications for audit processes, monitoring, calibration, and requirements for repeat surveys. SCANNER Surveys for Local Roads Specification Volume 4 Advice to Local Authorities is available in the table below.

It should be noted that Volume 5 did not require any updates; therefore the 2009 version is still being used, which is available in the table below.

Individual SCANNER parameters can be used to identify lengths containing particular types of defect. However, the SCANNER Road Condition Index (RCI) was developed through the SCANNER research programme to combine SCANNER defects into a single value to assist in the assessment of road condition. The approach used to combine the SCANNER defects was developed by Cartwright & Pickett (2004). This was used with an initial set of thresholds and weightings to calculate the ‘original RCI’ for 2006 and 2007. Further research (McRobbie, Walter, Read, Viner & Wright, 2007) led to new thresholds giving a ‘revised RCI’ which has been used since 2008.

The revised SCANNER RCI is calculated using a sub-set of the parameters measured by SCANNER (these are referred to as the core parameters), which are:

• Maximum rut depth
• 3m Moving Average Longitudinal Profile Variance
• 10m Moving Average Longitudinal Profile Variance
• Whole carriageway cracking
• Texture depth

To obtain an RCI value each parameter is scored between two thresholds – a lower threshold below which there is no need to consider maintenance and an upper threshold above which further deterioration does not increase the score. These thresholds were based on engineers’ experience of each parameter. The score increases linearly between the lower and upper threshold from zero at the lower threshold to 100 at the higher.

The score for each parameter is then multiplied by two factors, each having a value between zero and one. One factor reflects the “relevance” or importance of the measurement to the maintenance condition of the road. The other reflects the “reliability” of the method of measurement. The result is a weighted score for each parameter for the 10m subsection.

Note that, to avoid Longitudinal Profile Variance having a disproportionate effect on the reported condition, the weighted scores for 3m Moving Average Longitudinal Profile Variance and 10m Moving Average Longitudinal Profile Variance are compared, and only the largest of these two scores is taken forward to contribute to the calculation of the RCI. The same is true for rutting, with only the maximum of the offside and nearside rut depths being taken forward to the calculation of the RCI.

The weighted scores are summed to give a single RCI value for each 10m subsection length, representing the overall condition. The SCANNER RCI values reported by SCANNER can be used by highway engineers (often by displaying the data on a map background in a GIS) to identify lengths of the network in need of further, more detailed, investigation.

SCANNER National Indicators for local roads

The RCI values for each 10m length can be summed to determine the overall percentage of the 10m lengths within the network falling into three categories:

• "GREEN" - lengths where the carriageway is generally in a good state of repair (low RCI values). Green lengths have an RCI score below 40.
• "AMBER" - lengths where some deterioration is apparent which should be investigated to determine the optimum time for planned maintenance treatment (mid-range RCI values). Amber lengths have an RCI score over 40 and below 100.
• "RED" - lengths in poor overall condition which are likely to require planned maintenance soon (i.e. within a year or so) on a "worst first" basis (high RCI values). Red lengths have an RCI score of 100 or over.
  In England, Local authorities can use UKPMS to obtain the proportion of the network in the "red" category, which is reported as the Single Data List items 130-01 (‘A’ class roads) and 130-02 (other classified roads) for their network. These were formerly National Indicators 168 and 169 respectively.
  The parameters, thresholds and weightings that define the calculation of the RCI are published on the DfT website as a “Weighting Set”, which can be found here.