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 Inventory

Item Inventory is currently used in UKPMS for the following purposes:

1. To 'refine' the Pavement Type that is associated with a Defect recorded in a Condition Survey. For example, the Defect "Wheel Track Major Cracking" on a "Bituminous Surface, Unknown Construction" Carriageway, might be transformed using inventory information into "Wheel Track Major Cracking' on a "Covered Concrete" Carriageway

2. For Defects recorded in DVI’s (Detailed Visual Inspections), to calculate the Defectiveness of the observed Defect and hence assign a Rating value to the Defect. For example, the extent of the Defect BCRJ (Major Cracking on a Bituminous Surfaced Carriageway) might be recorded as 80 square metres over a chainage interval of 20 metres. The corresponding lane area, derived from the inventory, might be 200 square metres thus giving a Defectiveness of 40% (i.e. 80/200).

3. To calculate the estimated works costs of the treatments generated by the Treatment Selection process. Linear extents or areas of Features are calculated and combined with unit cost rates.

The user may opt to operate UKPMS without inventory and to the use 'Default' Inventory. Alternatively, the user may choose to refine the UKPMS results by collecting and maintaining an explicit Item Inventory. It may also be that such an Item Inventory, perhaps collected for routine maintenance or asset management purposes, already exists, and it would clearly be advantageous to make use of it for UKPMS purposes.

The exception to the above is the Concrete Joint Inventory. Users wishing to process Concrete Joint Defects for a DVI survey must have a corresponding Concrete Joint Inventory. There are no defaults.

The decision on whether or not to collect condition data will depend on the condition data being collected, and on the use that will be made of the system.

Note that the UKPMS Inconsistency Report allows users to highlight discrepancies between data collected in Condition Surveys and the Item Inventory, but that there is no enforcement of correspondence between condition data and inventory data at a chainage and cross section position level.

Some inventory collection is required on Footways, to allow the production of the BV187 Performance Indicator, including the recording of Footway Hierarchy at the chainage level. See Technical Note 29 for further information.

The following Features

Carriageways
Cycletracks
Footways
Verges
Kerbs

Comprise the Paved Surface inventory. The geometry of Kerbs is defined by start and end chainage only. For other items widths are also recorded.

If a Paved Surface inventory is recorded, the minimum attributes to be maintained for a Section, Feature and XSP are:

Start Chainage
End Chainage
Start Width (not for Kerbs)
End Width (not for Kerbs)
Feature Hierarchy (for footways and optionally for other features)

This minimal set of data does not support the refining of Defects based upon Construction Type described in above, and which allows - for the Defects and Construction Types currently set up for UKPMS - the user to distinguish between, and to separately consider, Covered Concrete and fully flexible Bituminous surface types. In order to do so users must maintain

Construction Type

as well. The ability to maintain Construction Type as an attribute of an inventory item is mandatory for UKPMS Comparability, as is the ability to transform Defects based upon those defects.

In practical terms, it is unlikely that a user will have comprehensive information on construction types in an initial implementation of UKPMS. The intention is that such information would build up over time as and when new works are carried out, or be determined from coring and investigation works. Given that Construction Type represents the 'invisible' properties of a pavement, it is far more likely that the 'visible' Surface Type - which plays no algorithmic role in UKPMS - will be available as an attribute of an inventory item, particularly where an existing inventory is being utilised for an initial implementation. In practice, Surface Type will be same as Construction Type, in all instances except for bituminous surfaced carriageways. For these, users will either have to make an initial assessment of construction based upon local knowledge, site inspections or historic records, or assume flexible or rigid construction at a network or sub-network level, according to the locally prevalent construction type. Setting the rule data for 'unknown' Construction to be the same as flexible or covered concrete construction as appropriate, will have the same effect. Note that for the rule data supplied for the comparability tests, this approach has been taken, with flexible construction rules taken as the default where construction is unknown.

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