Intersection Modelling (SIDRA)

Intersection modelling assesses how intersections and site access points perform under existing and future traffic conditions. Using SIDRA Intersection, software widely used by road authorities across Australia, we model roundabouts, priority-controlled intersections and site accesses to determine whether they can accommodate the traffic generated by a development. Key outputs of intersection modelling include:

  1. Degree of Saturation: The ratio of traffic demand to capacity for each movement, which shows how close the intersection operates to its capacity.

  2. Average Delay: The average delay experienced by vehicles on each approach and movement.

  3. Level of Service: A rating from A to F that summarises intersection performance based on average delay.

  4. Queue Length: The 95th percentile queue on each approach, used to confirm that queues will not extend through adjacent intersections or block site access.

We build our models from site-specific traffic surveys, then test future scenarios that include background traffic growth and development traffic. Where the modelling identifies capacity constraints, we develop and test intersection treatments to find the most effective solution.

Councils and road authorities often require intersection modelling for larger developments, rezonings and sites with access to arterial roads. Our modelling covers:

  • Site access intersections for residential, commercial and industrial developments.

  • Roundabouts and priority-controlled intersections in urban and regional settings.

  • Intersection upgrades, such as turn lanes, additional approach lanes and changes to intersection control.

  • Cumulative traffic impacts from staged developments.