PAS2161 FAQs

Location

The trials will be based in Nottinghamshire, Lincolnshire and Cheshire West & Chester.

TRL has determined three local authority areas which will still collectively offer variability in condition, terrain, road constraints, road type and an appropriate urban/rural mix, as well as continuous routes. i.e. although in the same general region, the three areas selected offer as much variety as possible.

Route details

The overall route length on which local authority engineers will establish the benchmark and on which the technologies will be tested is circa 100km in each of the three local authority areas. The subset road length will be 25km of the main route in each area and the technologies will need to establish condition category data twice on each of those subsets to establish repeatability. So, that means a total main route length of 300km and a total repeatability length of 150km.  

The technology survey process must be the same for all forms of technology. If a technology is unable to complete the full survey (i.e. totals of circa 300km of main route and 150km of subset repeat surveys), the technology will be considered as ‘not demonstrated’ for the 2026 audit.  

There is an overall 4-week window in which to undertake the main route and subset route surveys at all three local authority areas. There is no specific requirement to undertake the main route survey and two subset repeatability route surveys on different days.

Although the majority of local authority highway networks are unclassified roads, the application of PAS 2161 and the reporting of condition date by local highway authorities is for classified roads. Unclassified roads are used as part of the trial to help ensure that survey routes are continuous but also because they can generally offer categories 3, 4 and 5 conditions for the assessment process. The split between the different classifications of roads is as set out in the following table.
Percentage
Class A26.5%​
Class B31.2%​
Class C26.3%​
Class U16.0%​

Data provided by TRL

TRL intends using the same approach in 2026 as it did for 2025. The local highway authority engineers are expected to be different individuals but, by taking a regional approach, those involved this year may be better placed to survey at least 2 if not 3 areas, bringing a more consistent viewpoint to the benchmark.

In the 2025 demonstration trial, 20% of the main routes in Cumberland, Liverpool and Essex was initially provided as benchmark survey calibration data. This was later considered to be insufficient so 100% of the Essex data was provided to better enable overall calibration. To avoid the need to provide supplementary calibration data in the 2026 trial, 40% of each of the three areas’ main route benchmark survey results will be shared. TRL will examine 100% of the technology condition category data from the technology providers but the 60% of route data not shared may offer TRL greater insight into technology performance.

This has not yet been determined but it may prove more insightful for TRL’s assessment if the calibration data does not cover all or even some of the subset routes.

The condition category chart is presented in PAS2161. Reproduced below.

CategoryDescriptionPotential maintenance treatment option
1No deteriorationPavement is not considered for maintenance
2

Minor (and/or aesthetic)

deterioration

Light maintenance

(e.g. minor patching)

3Moderate deterioration

Localized intervention or mid-life preventative maintenance

(e.g. surface dressing, patching, crack sealing)

4

Moderate to severe

deterioration

Rehabilitative maintenance, perhaps full carriageway

(e.g. resurfacing with thin overlay/surface dressing and multiple

patching, edge haunching)

5Severe deterioration

Structural maintenance

(e.g. full carriageway resurfacing or reconstruction)

NOTE: The examples of maintenance treatment options provide general, not definitive, descriptions of some of the maintenance treatments that might be considered by a typical Highway Authority engineer to restore a length in that RCM condition category to a condition that does not require maintenance. They are provided for guidance only and are non-exhaustive. Benchmarking of categories, and the ability of RCM devices to report them, is established through comparison with consensus assessments of highway engineers (see Annex C of PAS2161).

As far as reasonably practical, TRL has identified main survey routes in the three areas that have a reasonable blend of all condition categories. This is part of the challenge in identifying the right routes – and that is dependent on the richness of condition data provided by potential host authorities. Where forward programmes of planned major interventions are shared and such work will take place from October 2026 onwards, there is a good chance that a greater proportion of condition categories 4 and 5 will be available for both engineer benchmark and technology surveys.  Ultimately, local highway authorities have a statutory duty to maintain their networks and that includes taking remedial measures in a timely fashion. Intervention may inevitably take place between route selection and actual survey, but TRL will address any circumstances where remedial work takes place prior to completion of all technology surveys.

That would be an alternative approach but very difficult to achieve. Until the local highway authority engineers conduct their condition assessments of the main routes, there’s no realistic way of determining what percentage of those routes will fall into each of the 5 condition categories. TRL will try to achieve condition variability as much as it can, but that does depend on the richness of asset management and road network data provided by the host authorities, what their reactive and planned maintenance work programmes are, and any condition changes (e.g. arising from heat damage, flooding, extraordinary traffic loading) that may arise in the period between route establishment and survey.

The creation of the engineers’ benchmark is through the local highway authority engineers being driven round the 100km routes, making a visual assessment of the condition and assigning the condition category to 10m sections. As such, there is no ‘footage survey’ that would be shared. Under ordinary circumstances, the local highway authority will expect a road condition monitoring technology provider to conduct a survey and present condition results – the local highway authority would not expect to have to survey its network and provide a footage survey. So, the demonstration process needs to fully demonstrate how a technology provider would deliver a service to any local highway authority – and that includes the survey itself.

Yes, that’s correct. 100m data is used to mitigate the impact of location inaccuracies in the engineer and road condition monitoring technology data. However, 10m data will also be used to inform decisions on future analysis methods. Full details of how the data is analysed can be found in the 2025 report at PPR2083 PAS2161 2025 RCM Trials Final Report.

Data collection by and provision from technology providers

The 2026 data collection and engineer benchmark surveys will be as set out in the table below
LocationStart of data collection windowEnd of data collection windowBenchmark data collection
NottinghamshireMonday 24th AugustSunday 20th September25th to 28th August
LincolnshireMonday 31st AugustSunday 28th September15th to 18th September
Cheshire West & ChesterMonday 31st AugustSunday 28th September8th to 11th September

The Engineers Guidance can be found on the website by accessing the relevant document in the zip file on the PAS 2161 website at Demonstration Trial Routes – PAS 2161

TRL cannot provide legal advice. We urge you to take the appropriate steps to ensure that your surveys are both legal and safe. You have permission from the three local authorities involved in these trials to survey their networks, but again you must ensure that your surveys are both legal and safe. If you are unable to survey sections of the given networks, we will take this into consideration during the analysis of your data, providing we are notified.

There is no need to declare dates. Just be within the time window. You may require TRO exemptions, which you will need to provide dates for.

TRL has used local highway authorities planned work to guide the selection of the routes. It has then reviewed the proposed routes with the LHAs to make sure there are no planned works during the assessment timeframe. However, this does not rule out emergency works that will take place. If during your survey you find that there are emergency works taking place, please let TRL know immediately.

A gap report form is provided on the website – technology providers will need to complete this for any missing/uncollected data.

There is no defined maximum figure. It would be at the discretion of the Department for Transport once TRL has collected all the assessment data from providers. Reasons are to be given for missing data in a ‘Gap report’. If, for example, a road is closed due to maintenance or an accident, this would be considered an acceptable reason. If the road has been maintained during the trials, TRL will very likely exclude it from the assessment anyway. If numerous data providers report that the same section was inaccessible, again it will probably be excluded. If there is a reason that large lengths of the network cannot be accessed due to a limitation of the technology, then TRL and the RCM technology provider would need to have a discussion about the assessment procedure and any limitations that might have to be provided on the device(s) for commercial use. An extreme example might be if a survey vehicle is too wide to be able to access ‘C’ class roads. TRL should be contacted if an RCM technology provider thinks there may be a genuine reason for being unable to provide ‘good’ coverage of the demonstration network.

To provide a level playing field for all participants, the demonstration trials require that everyone provides a ‘Combined’ score for each section. This is why the engineers will also be providing a ‘combined’ score, with the method they will be using to do so defined in the Engineers’ Guidance document. Each section therefore needs to be scored with a value that represents the condition of all available lanes. For a two-way single carriageway section with four lanes, that is all four lanes. Dual carriageways which are represented as two separate sections only require the one section/carriageway in the route to be scored, but again, all lanes.

The coordinate reference system used for sharing the routes will be OSGB36.

This is a decision for RCM technology providers. The only requirement is to make sure the repeats are separate to the main files.

Section 7.2 of PAS2161 describes the fitting of data to the defined network. Sections can be of any length (within reason). They are defined by the highway authority according to various rules which mean a section label will change where a particular physical attribute changes, such as at a junction or if the section function changes, for example. RCM technology providers are expected to deliver data to match the sections as defined. Sub-sections of nominally 10m begin at the beginning of a section at 0m. They have a start distance and end distance, within the section. An example is shown in the PAS in AppA.

The method used is described in PPR2083 – but TRL will assess data in 100m lengths.

The RCM technology providers will provide 10m data. TRL will create 100m lengths for assessment, using the same process for everyone.

An example of PAS2161 data aggregation. The example data contains 5 random 1-5 categories over a 237m section for five engineers (A-E):

 Chainage

A

B

C

D

E

0-10m

1

1

1

2

2

10-20m

3

3

4

2

2

20-30m

2

2

2

2

2

30-40m

2

2

2

2

2

40-50m

3

3

3

3

3

50-60m

2

2

2

3

3

60-70m

4

3

2

2

3

70-80m

5

5

5

3

4

80-90m

2

2

2

2

2

90-100m

2

2

2

3

3

100-110m

3

3

2

2

2

110-120m

1

1

1

1

1

120-130m

1

3

2

2

2

130-140m

1

1

1

3

3

140-150m

1

2

2

2

3

150-160m

2

2

2

2

2

160-170m

1

1

1

2

1

170-180m

1

1

1

2

1

180-190m

4

3

3

3

3

190-200m

1

1

1

1

1

200-210m

1

2

2

1

2

210-220m

2

3

4

4

2

220-237m

2

2

2

2

2

The method of max mode (i.e. calculate the mode, if there is a tie in the counts, choose the category of the highest condition score) is applied to the condition scores for every 10m -sub-section. For example, the counts of the category scores for 0-10m:

Category

1

2

3

4

5

Count

3

2

0

0

0

Category 1 has the highest count, so condition score 1 is the assigned to the sub-section.

The counts of the category scores for 10-20m are:

Category

1

2

3

4

5

Count

0

2

2

1

0

Categories 2 and 3 have the highest counts, since 3 is the largest condition score (i.e. 3 > 2) condition score 3 is assigned to the sub-section.

The table below shows the results of applying the method on the full table:

 Chainage

 Category

0-10m

1

10-20m

3

20-30m

2

30-40m

2

40-50m

3

50-60m

2

60-70m

3

70-80m

5

80-90m

2

90-100m

2

100-110m

2

110-120m

1

120-130m

2

130-140m

1

140-150m

2

150-160m

2

160-170m

1

170-180m

1

180-190m

3

190-200m

1

200-210m

2

210-220m

4

220-237m

2

The data is then aggregated to 100m by summing the weights for each category and choosing the category with the largest weight (if there is a tie, choose the category with the highest condition score). The weight is given by the length of the section i.e. [end section length – start section length]. This approach is equivalent to C.3 in PAS 2161. For the chainage 0-100m, the weights table is:

Category

1

2

3

4

5

Weight

10

50

30

0

10

The condition score 2 is has the highest weight, so Category 2 will be assigned to the 100m sub-section.

For the chainage 100-237m, the weights table is:

Category

1

2

3

4

5

Weight

50

67

10

10

0

The condition score 2 is has the highest weight, so Category 2 will be assigned to the 137m sub-section.

If a section or lane has a TRO preventing access to it, arrange for an exemption from the TRO from the relevant local authority, as would happen under normal survey circumstances. In the case of the demonstration trials, TRL are acting as the local authority and will pass on any requests to the actual local authority. There are such sections in the trial routes, which you should consider when you plan your data collection.

TRL is not providing advice on how to perform data collection or processing. The DfT has requested a ‘combined’ value for all sections (as per 4.5a1 and 4.5b1). It is up to RCM technology providers how this is provided.

‘Forward’ refers to the direction of the section (line string). The section starts at 0m and proceeds ‘Forward’ towards the end length of the section. For CR1 lanes, assuming you are driving your surveys on open roads, you will collect data in the ‘Reverse’ direction. i.e. the direction of travel is not the same as the direction that the section is defined in. Note, that for data collected on two-way roads, where delivered as a ‘combined’ category, it will require at least one of the lanes to be flipped.

The demonstration trials are intended to assess the entire process. As such, an engineer counts as both a ‘device’ and for at least part of the ‘data processing’. TRL would expect that, as per 9.5.b, RCM technology providers have a documented process in place to both train and to maintain a suitable level of competence for the engineer(s).

The dataset being provided is the only data that will be made available. It will be generated by combining the scores of multiple engineers and removing outliers to ensure good confidence in the result(s). The same process will be applied to the benchmark data that RCM technology providers will be assessed against.

The dates for the calibration work is as set out in the table below.

LocationDate
TRL provides benchmark data for calibration2nd October 2026
RCM technology providers submit calibrated data for assessment6th November 2026

Please share any issues through the RCMtrial@trl.co.uk email address.

The QA form submission deadline is the same as the data submission (i.e., 6th November). If there are issues that need to be resolved, but insufficient time is available to do so, it will not be possible to issue a certificate of demonstrated status.

The reason for two data submissions in 2025 was because the original provision of 20% calibration data on the three networks of Cumberland, Essex and Liverpool proved to be insufficient to allow full calibration. To overcome that, 100% of the Essex data was provided which then enabled a second submission to be made. For the 2026 demonstration trial, calibration data for 40% of all three networks will be provided which should suffice for a single data submission.

No changes are planned to the data output report format for 2026 to that in 2025.

Such features should be recorded as you feel is appropriate for your data collection methodology, so that the results represent condition as per PAS2161.

Repeat routes are for the purpose of assessing repeatability. They represent a different data collection exercise and should be delivered as separate files.

TRL only needs the data necessary to assess the performance of each road condition monitoring technology type for use on the classified road network. It is up to the RCM technology provider to determine if there is any additional information that it considers its existing or potential clients would benefit from, including the ability to produce survey information for the unclassified road network. It is the aspiration of the Department for Transport and TRL that there is some (as yet unspecified) improvement in performance from RCM technology providers for the 2028 and 2030 trials, rather than an expansion in capability.

It is not TRL’s role to act as advisors to RCM technology providers as that falls outside of the scope of its contract with the Department for Transport. TRL is following the requirements of PAS 2161 and can only certify that a road condition technology is either ‘demonstrated’ or ‘not demonstrated’.

The generic answer to this is that, since the network definitions used for the trials have been sourced from real local highway authorities, then you should do what you would normally do during commercial surveys. Network definitions provided by local highway authorities can sometimes be inaccurate or out-of-date. In addition, there is often no relationship between the recorded section length and the digitised length of the section. These are two sources of the same information, but they do not necessarily have to match. The recorded section length may have come from a measuring wheel, or an existing automated survey, whilst the digitised section length is subject to the skill and precision of the individual drawing the line on a map. In such cases, an RCM technology provider would either make decisions based on prior experience or consult with the local highway authority for clarification. Since for the purpose of the demonstration trials, TRL is acting as the local highway authority, TRL’s answers to your questions would be:

  1. Please use and fit data to the section lengths given in the spreadsheet definition of the network.
  2. This is the network definition. Please attempt to survey as much of the defined network as possible. Report any missed length(s) in the Gap report.
  3. This is an inconsistency in the digitisation. Please use and fit data to the spreadsheet definition of the network.

Demonstrated/not demonstrated

There is no intention to change the pass marks that applied for the 2025 demonstration trial in the 2026 demonstration trial. It is the aspiration of the Department for Transport and TRL that there is some (as yet unspecified) improvement in performance from RCM technology providers for the 2028 and 2030 trials.

All technologies will be assessed on the same assessment criteria. However, due to the nature of the technologies, some Type-V (Telematics) might collect data for assessment of repeatability using a different approach. If you intend to provide Type-V, please contact RCMtrial@trl.co.uk as soon as possible to initiate a discussion.

There will always be some degree of variability of interpretation of condition amongst engineers. Even when the local highway authority engineers are deployed to determine a demonstration trial benchmark, there are different interpretations of condition. The Department for Transport requires that the ‘technologies’ being offered for demonstration are capable of delivering RCM data. Therefore, the engineer who makes the assessment of the rating is considered part of that technology. They are a human element in the data processing chain. Any engineers for Type E technology should therefore have sufficient understanding and experience of road condition monitoring to make a reasoned assessment of condition into categories 1 to 5. The RCM provider of category E will need to identify the procedures that it will have in place to ensure, as much as possible, that its different engineers provide consistent ratings.

The pass thresholds for the 2025 demonstration trial are as shown in Table 8 of PPR2083. It is currently anticipated that they will remain the same for the 2026 demonstration trial.

Any scenario whereby multiple organisations are working in partnership requires full working alignment between those organisations. PAS 2161 allows for the data processor to be a different organisation to the data provider but the technology being assessed requires collaboration. If that collaboration is not sufficiently evidenced through the quality assurance form process, the technology will be ‘not demonstrated’.

The intention is to formally announce which technologies are ‘demonstrated’ on 18th December 2026. If there is any scope to do so, the announcement will be brought forward, but it very much depends on how the trial progresses.

No. The accreditation is for a specific technology for which the named company/companies have also been assessed in terms of quality assurance. Another company could use that specific technology, but it will not be considered as accredited as that company will not have undergone (and been approved under) the quality assurance assessment process. It would also be necessary to confirm that the implementation of the technology is consistent between the two companies.

Note: If a local highway authority does not use an accredited arrangement, it risks losing part of its (in some cases, substantial) annual capital funding allocation from the Department for Transport. The local highway authority would be justified in seeking financial damages from any organisation that claimed to be providing an accredited road condition monitoring technology but was unable to later prove that to be the case.   

Finance

The RCM technology provider submitting the request for approval of any technology may be a data collector being supported by a separate data processor, a data processor being supported by a separate data collector or a single organisation that acts as both data collector and data processor. Any of those three arrangements would be regarded individually or collectively in partnership as an ‘RCM technology provider’ with each separate organisation named on the accreditation certificate.

The £7,500 cost is per technology for the 2026 demonstration exercise. The cost for future demonstration exercises is likely to be similar but will be confirmed before each demonstration exercise.

The £7,500 cost is per technology. If a data collector and data processor are from different organisations, the cost remains £7,500 – but those two organisations would need to mutually agree how to apportion the cost and who would act as the lead organisation for the purposes of ensuring the issue of a purchase order and subsequent payment of the invoice that TRL will generate.

As part of the procurement process, the Department for Transport requested all potential bidders to submit a fixed price for assessing each technology. As part of its tender submission, TRL set a price of £7,500 per technology so any interested party must similarly follow suit and submit a payment of £7,500 for its technology to be assessed against PAS 2161 by TRL.

The accreditation certificate will state the name of the company – or companies if the data collector and data processor are distinctly different entities – and the technology that has been demonstrated.

General queries

Any queries (technical or financial) not addressed in this Q&A document should be directed to the dedicated TRL email address of RCMtrial@trl.co.uk

No, there is currently no defined dispute resolution process established for the relationship between the customer (local highway authority) and the provider. That would be a contractual issue between parties.

TRL has not been tasked to provide such a service between providers and local highway authorities. However, as part of the goal to improve future performance, TRL would like to be informed of any such disputes so that any clarifications required can be discussed with the DfT and incorporated into future guidance.

RCM technology providers interpreted some of the questions posed on the quality assurance form in the 2025 demonstration trial differently. So, for the 2026 trial, there have been technology-type specific questionnaires. This will reduce the instance of questions that are not appropriate for the technology, and, in addition, it would allow for additional guidance and examples which would be relevant for the technology type.  Each RCM provider will need to demonstrate (via the QA forms) that they have acceptable QA arrangements in place which they will carry out over the life of the demonstration certificate. TRL will review the responses to the QA forms and provide feedback.  However, TRL has not been tasked with reviewing/auditing QA undertaken between demonstrations.

The PAS 2161 2026 demonstration trial will assess all RCM technologies that can potentially be used by local highway authorities until the end of March 2029. Any technologies that emerge after the conclusion of the 2026 demonstration trial will have the potential to be assessed in the 2028 and 2030 trials.

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