Best Value Performance Indicator BV96 - 2004/05

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Introduction

For the Financial Year 2004/05, TRACS-Type Surveys (TTS) are the only permitted survey option for the calculation of BV96 on Principal Roads.

The TTS-based indicator is intended to identify the percentage of roads that require further investigation and will not necessarily correlate with the lengths of proposed treatment output from UKPMS processing. In practice, the TTS-based indicator may return a different value from early versions based on either UKPMS visual or Deflectograph surveys as it is derived from different data.

TRACS-Type Surveys

TRACS-Type Surveys are automated high-speed surface condition surveys, based on the Highways Agency TRACS Contract and adapted to be suitable for the Principal Road Network. TTS surveys collect the following data:

  • 3-Dimensional Spatial Co-ordinates
  • Road Geometry
  • Survey Speed
  • Longitudinal Profile
  • Wheelpath Rutting
  • Texture Profile
  • Cracking (both in the vehicle wheel paths and for the whole testing lane)

Survey Specification and Quality Provisions

The requirements for each of these data items, including accuracy and coverage requirements, as well as methods for their acceptance, are given in the TTS Advice Note and Specification Version 1.0 which is published by the Roads Board and is available from the DfT and UKPMS websites.

Local Authorities should insist that Survey Contractors fully comply with the requirements of the TTS Quality Assurance and auditing procedures that form part of the TTS Specification.

Only data collected using Survey Equipment possessing a valid TTS Acceptance Certificate, that explicitly states that the survey vehicle has been approved for use in the production of Best Value Performance Indicators, may be used in the calculation of BV96.

Survey Coverage

For 2004/2005 the following provisions apply for the programming and reporting of TTS surveys:

  • 100% of the network will be reported each year (nearside lane in each direction 1 ).
  • The BVPI must be derived from surveys carried out during the period 1 April 2004 to 31 March 2005.
  • All road surface types are included.
  • "Deemed coverage" will not be permitted.

TTS Surveys should be carried out in the nearside lane on all Principal Roads including Single Carriageways, Dual Carriageways and Slip Roads. Roundabouts that have been referenced as separate sections are, however, excluded from the survey, since it is difficult to achieve consistency of survey on such sections

Data Supply and Processing

The data will be delivered as a HMDIF file, called a TTS BCD file in the TTS specification, that can be loaded into Local Authorities' UKPMS-accredited systems either for the calculation of BV96 or to assist in the development of highway maintenance programmes.

Calculation of the Indicator

Processing of the outputs from TTS to produce BV96 results will be undertaken using a Tranche 3 UKPMS-accredited pavement management system using Version RP5.01* of the UKPMS Rules and Parameters.

The indicator is the percentage of the Principal Road Network (i.e. the percentage of the total network nearside lane length) with at least one defect having triggered the thresholds given in the table below. The thresholds generally correspond to Condition Category 3 (Moderate Deterioration), as defined in the TTS Advice Note and Specification Version 1.0, but they do not vary by road type or surface type.

Defect

Threshold

Nearside Texture Depth

Less than or equal to 0.6mm

3m Longitudinal Profile Variance

Greater than or equal to 4mm2

Nearside Rut Depth

Greater than or equal to 11mm

Offside Rut Depth

Greater than or equal to 11mm

Whole Carriageway Cracking Intensity

Greater than or equal to 0.5%

The following information should also be provided to support the BVPI:

UKPMS System & Version

  

Version of Rules & Parameters Used

  

Copy of Valid TTS Accreditation Certificate

  

Reasons for reduced survey coverage (if applicable)

  

Other Comments

  

* - UKPMS Rules and Parameters RP5.01 will be the version of the UKPMS Rules and Parameters released to UKPMS Developers on 30 September 2004 for implementation by 31 December 2004. UKPMS Rules and Parameters Version 5.01 will form the basis of both the BVPIs for 2004/05 and the 2005 UKPMS Annual Health Check.

1 At locations with Bus Lanes, Crawler lanes and other lanes that do not carry all types of traffic the surveyed lane(s) will not necessarily be the lane(s) nearest to the edge of the carriageway.