Introduction
UKPMS Comparability Testing
Accredited UKPMS Systems
The 3 Tranches of UKPMS Functionality
· Tranche 1
· Tranche 2
· Tranche 3
HMDIF
Rules and Rule Sets
Feature Hierarchy
Best Value Performance Indicators
UKPMS Condition Surveys
· Coarse Visual Inspection
· Detailed Visual Inspection
· SCANNER Surveys
· SCRIM
· Deflectograph
· Machine-Measured Rutting
UKPMS Location Referencing
· Section Referencing
· Chainage and Feature Referencing
· Cross Section Position Referencing
UKPMS Inventory

UKPMS Condition Surveys

Coarse Visual Inspection

The Coarse Visual Inspection or CVI, is intended to be a coarse, rapid survey, usually carried out from a slow-moving vehicle, that allows a large part of a highways authority’s road network to be assessed each year.

CVI is the standard survey used to produce the Best Value Performance Indicators on the condition of local authorities’ roads as required by the government, and which allows comparisons to be made between authorities on the basis of the overall condition of their carriageways.

A CVI survey is normally undertaken from a slow moving vehicle, using the “simple” cross-section position method, where the carriageway is assessed as a whole, and kerbs, footways and cycletracks are separately inspected for the left and the right of the carriageway.

Detailed Visual Inspection

The Detailed Visual Inspection or DVI, is a more comprehensive survey than the CVI, with defects identified by a larger number of more detailed classifications. The DVI is a walked survey, and is typically targeted at lengths already identified as defective and potentially in need of treatment either by the CVI, or from some other sources of information.

The DVI records measured areas or lengths for a wider range of more closely defined defects (than for CVI), aggregated within short sub?sections, 20 metres in length by default. The defects collected for DVI are generally defined to a closer level of detail than CVI. In order to ensure broad consistency between the two surveys a single CVI defect is normally equivalent to a number of DVI defects.

It is intended that DVI is used where more detailed information is required to support and validate treatment decisions and scheme identification, supplementing CVI data; it may also be used on a cyclical basis for parts of the network where a more detailed routine visual assessment is required or where driven surveys are not possible.

If DVI surveys are to be used to produce Best Value Performance Indicators, then they should be converted to CVI-equivalent data using the UKPMS Conversion Software.

SCANNER Surveys

SCANNER Surveys are high-speed surface condition surveys, based on the Highways Agency TRACS Contract and developed to be suitable for the Principal Road Network. SCANNER collects the following data:

- 3-Dimensional Spatial Co-ordinates
- Road Geometry
- Survey Speed
- Longitudinal Profile
- Wheelpath Rutting
- Texture Profile
- Cracking

Additionally, measures of edge condition and transverse uneveness are being developed.

Further information is available in the SCANNER Specification. It is intended that traffic speed surveys will be further developed for used on local roads over the coming years.

SCRIM

SCRIM (Sideway-force Coefficient Routine Investigation Machine) was introduced in the early 1970s to provide a method of measuring the wet skidding resistance of the road network. The normal testing speed for the machine is 50km/h and skidding resistance values for the nearside wheel track only (usually the location of the lowest skidding resistance) are generally recorded as the average for each 10m section.

The principle of the machine is that a test wheel, mounted mid-machine in line with the nearside wheel track and angled at 20° to the direction of travel, is applied to the road surface under a known load. A controlled jet of water wets the road surface immediately in front of the test wheel, so that when the vehicle moves forward, the test wheel, whilst rotating freely in its own plane (thus allowing uniform wear on its test wheel tyre), slides in the forward direction on a wet road surface. The force generated by the resistance to sliding is related to the wet skidding resistance of the road surface and measurement of this sideways component allows the sideway-force coefficient (SFC) to be calculated.

SCRIM surveys are processed differently from other surveys types within UKPMS, in that they make use of “Functional” defects. These defects always prompt treatment if they are below the target threshold. The treatment that is suggested will depend upon what other defects, from other surveys, exist at the same location.

Deflectograph

The Deflectograph is used to assess the structural condition of flexible and flexible composite pavements. It works on the principle that as a loaded wheel passes over the pavement, the pavement deflects and the size of the deflection is related to the strength of the pavement layers and subgrade.

The Deflectograph is an automated deflection measuring system. It is a fully self-contained lorry-mounted system, whereby measurements of deflection are taken at approximately 4m intervals in both wheelpaths while the machine is in motion.

Machine-Measured Rutting

For both survey types, but especially for CVI surveys, although it is possible to assess Wheel Track Rutting manually, either using a straight edge and wedge or depth measure for DVI surveys or by visual assessment for CVI surveys, the preferred option is to measure rutting using machine-based options, either as part of a CVI surveys, or as a separate rut survey.. Two special survey types of Machine Collected Rutting for DVI (DRUT) and Machine Collected Rutting for CVI (CRUT) have been created have been defined to support the loading and processing of such with visual surveys. Appendix 11 of the UKPMS Visual Survey Manual gives more details. This is recommended both on grounds of accuracy, and for DVI surveys, safety, since it removes the need to walk onto the carriageway.

 
 
Produced by Chris Britton Consultancy Ltd on behalf of the UKPMS Owners Forum