AP-G84/04 Best practice in road use data collection, analysis ... - WIM

Accessed by AR - ARRB TRANSPORT RESEARCH on 04 Feb 2005
2 BEST PRACTICE PRINCIPLES
Austroads 2004
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Best Practices in Road Use Data Collection, Analysis and Reporting
This section provides a brief discussion on the principles of best practice. The aim is to provide a
broad context in making recommendations in this report. These principles also relate to data
integrity issues, which will be addressed in more detail in Section 6. They are as follows:
Accuracy – This is a measure of how well the data collected represent true values. In traffic
data, perfect accuracy is unnecessary and it is actually impossible to achieve.
Consequently, it is good practice to quote a percentage error and the associated confidence
level. A trade-off between accuracy with other quality criteria is also necessary – higher
accuracy often implies higher cost.
Effectiveness – This is the likelihood that a work program achieves desired objectives. It
measures how closely outcomes match predefined targets.
Efficiency – This is the ratio of output to input. A lot of output data with minimal input
resources is an efficient data collection program. However, collecting the wrong data is an
ineffective program irrespective of the amount of input resources involved.
Reliability – This is related to accuracy. A counting program needs to produce consistent and
repeatable results. Reliability is therefore an outcome of how well a road network is sampled
or covered to produce statistically consistent data.
Accessibility – Road use data should be easily accessible within a jurisdiction and to the
public due to the Freedom of Information (FOI) Act, possibly not in the raw data form but in
aggregated form. The data structure and formats should be amenable to data accessibility.
Transparency – A clear enunciation of the procedures for collection, analysis and reporting
should help reducing differences amongst RAs and other users in the use and interpretation
of road use data.
Timeliness – This relates to the frequency of data collection, its reporting and updates. A
yearly update and reporting should be the minimal update period. With more and better
database technologies, it is expected that road use data would become more timely in the
near future.
Relevance – The data collected should meet the needs of a user, i.e. should fulfil the
principle of fitness of purpose. There is always a great need for traffic counts and weigh-inmotion
(WIM) data. A current issue is what other types of data should be included in a
comprehensive road use database.
The above list is certainly not exhaustive but does cover most of the important elements in
identifying best practices. These principles will be applied in the following sections to identify and
recommend practices in the final road use data report.
Further, a glossary of terms is included in Appendix A. The glossary is intended to be a ‘national
glossary’ to promote consistency. It is recognised that individual jurisdictions would adopt slight
variations in definitions and therefore practices due to constraints specific to a jurisdiction. Over
time, the national glossary also requires updates and is a reference towards which jurisdictional
practices would migrate.