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TRACS - Type surveys of the principle road network

An Advice Note and Specification was prepared by the Chris Britton Consultancy and TRL Limited on behalf of the UK Roads Board and first published in May 2003. A copy of the Advice Note and Technical Specification is available here.

The aim was to provide local authorities with everything they needed to make informed decisions about the procurement of TRACS-Type Surveys (TTS) for their principal road networks and to make best use of the resulting TTS data.

The document aimed to promote good practice in the procurement, operation and application of TTS and drew on the experience of those authorities that had implemented TRACS or TTS on their own networks, as well as other practitioners and technical experts.

The Department for Transport encouraged English local authorities to use TTS surveys carried out in 2003/04 to report BV96 in 2004, the Best Value Performance Indicator for the condition of principal roads.; However relatively few authorities reported BV96 based on TTS surveys.

The Department for Transport required English local authorities to use TTS surveys as the only permitted survey option in 2004/05 to measure the condition of principal road carriageways and report their condition as BV96 in 2005.

Further information is available from the Department's website at:

The BV96 indicator, based on TTS surveys, was the percentage length of the principal road carriageway where one or more of a number of measured parameters (or 'defects') exceeded predetermined thresholds. The measured parameters were left and right wheel path rut depth, 3m longitudinal profile variance, whole carriageway cracking intensity and texture depth. The thresholds were set to measure carriageway condition 3 - moderate deterioration, defined as the stage where deterioration was becoming serious and needed to be investigated. In the event, local authorities reported significantly larger values for BV96 obtained by TTS than using either Deflectograph or CVI surveys.

BV96 (%) Top quartile Median Bottom quartile
2004/05 TTS 28.97 39.01 47.98
2003/04 Deflectograph 6.68 9.31 15.00
2003/04 CVI 3.13 5.85 10.82