SIDRA Glossary of Road Traffic Analysis Terms

This glossary has been prepared to include the terminology of the SIDRA INTERSECTION and SIDRA TRIP software. This updated version includes traffic assignment terms with the inclusion of SIDRA ASSIGN functionality in SIDRA INTERSECTION Version 11. The sources used in preparing this document are the SIDRA INTERSECTION User Guide (2026), the Australian AUSTROADS Glossary, AP-C87-15 (2015), the US Highway Capacity Manual Glossary in Edition 7 (2022) and the UK Depart of Transport Highway Assignment Modelling Glossary (2024). This unique glossary includes many terms that are not included in the AUSTROADS and the HCM glossaries. An effort has been made to keep the definitions given in the AUSTROADS and HCM glossaries as much as possible, combine them together, modify as required and incorporate them into the definitions used in the SIDRA INTERSECTION software. The usage in SIDRA INTERSECTION takes precedence where there are discrepancies. Thus, many of the key analysis terms in this glossary have significant differences from those in the AUSTROADS and US HCM glossaries (mostly in the expression but sometimes in the meaning). It is hoped that they represent clearer and more general definitions, for example considering left-hand and right-hand traffic rules and different local traffic engineering practices.