What Does SIDRA Assign in SIDRA Version 11 Actually Do?
SIDRA Assign allows traffic within a modelled road network to respond more dynamically to congestion, delays and travel times rather than relying on fixed route assumptions.
In practical terms, it helps traffic modelling behave more like real drivers do by allowing traffic volumes to redistribute across available routes based on network conditions.
SIDRA Version 11: What SIDRA Assign Means
The release of SIDRA Intersection Version 11 introduced a significant enhancement to how traffic can be modelled across broader road networks through a feature known as SIDRA Assign.
For traffic engineers and transport planners, this functionality provides a more realistic approach to traffic assignment by allowing route choice within a model to respond dynamically to operational conditions such as congestion, queueing and travel time.
Historically, traffic assignment within many SIDRA assessments relied more heavily on predetermined routing assumptions established by the modeller before operational analysis was undertaken. While this approach remains suitable for many smaller or isolated assessments, more complex networks often require traffic movements to respond dynamically to changing network performance.
SIDRA Assign represents an important step toward more realistic network modelling within SIDRA Intersection.
What Changed in SIDRA Version 11?
Under traditional traffic assignment approaches, the modeller would generally estimate in advance how traffic was expected to distribute across available routes within the surrounding road network.
This meant that:
- route choice assumptions were often fixed prior to analysis
- traffic could remain assigned to congested routes even where alternatives existed
- network responsiveness to congestion was relatively limited
SIDRA Assign introduces a more adaptive process.
The software now considers factors such as:
- intersection delay
- queue lengths
- route travel times
- network congestion levels
Based on these conditions, SIDRA can redistribute traffic across available routes in a way that better reflects likely real-world driver behaviour.
This allows the network to respond more naturally to changing operational conditions.
A Simple Example
Consider a scenario where vehicles can access a shopping centre using two alternative routes:
- Route A is shorter but experiences significant congestion during peak periods.
- Route B is slightly longer but generally operates more efficiently.
Under a static assignment approach, traffic may continue to be allocated heavily toward Route A even when delays become excessive.
With SIDRA Assign, the model can recognise the increasing congestion on Route A and redistribute some traffic toward Route B if overall travel conditions are more favourable.
This produces a more realistic representation of how drivers often behave in practice when alternative routes are available.
Why SIDRA Assign Matters
SIDRA Assign becomes particularly valuable for developments and infrastructure projects that influence multiple intersections or broader road networks.
This includes projects such as:
- mixed-use developments
- shopping centres
- industrial precincts
- school master plans
- transport infrastructure upgrades
- road network reconfigurations
The functionality can assist in assessing:
- whether traffic may divert to alternative streets
- how congestion may redistribute across a network
- impacts of turning restrictions or access changes
- effects of signal timing adjustments
- network-wide operational performance
In practical terms, SIDRA Assign allows traffic modelling to better reflect how road users adapt to congestion and travel conditions within real transport networks.
Why More Realistic Assignment Improves Traffic Modelling
Traffic modelling is ultimately intended to represent how drivers behave within the real world.
Where assignment assumptions are overly rigid, models can sometimes overstate or understate impacts on individual roads or intersections because traffic redistribution opportunities are not fully considered.
By allowing route choice to respond to network conditions, SIDRA Assign can provide:
- more realistic operational outcomes
- improved understanding of network performance
- stronger assessment of cumulative impacts
- better-informed infrastructure planning decisions
This can be particularly important within urban renewal areas and growing activity centres where traffic conditions evolve dynamically throughout the day.
When SIDRA Assign Is Most Useful
SIDRA Assign is generally most valuable where:
- multiple route options exist
- developments influence several intersections simultaneously
- network congestion affects route choice behaviour
- strategic traffic redistribution is likely to occur
- cumulative traffic impacts require assessment
For isolated intersections with limited route choice opportunities, traditional assignment approaches may still remain appropriate.
As with any traffic modelling tool, professional engineering judgement remains critical in determining the appropriate methodology for a particular project.
The Main Takeaway
The core principle behind SIDRA Assign is relatively straightforward:
Rather than forcing traffic to follow fixed routing assumptions, the model allows traffic to respond more naturally to congestion, delay and travel time conditions.
This provides a more realistic understanding of how traffic is likely to distribute through a road network and improves the ability to assess broader operational impacts associated with development and infrastructure changes.
Frequently Asked Questions (FAQ)
What is SIDRA Assign?
SIDRA Assign is a feature within SIDRA Intersection Version 11 that allows traffic within a modelled network to dynamically redistribute across available routes based on congestion, delay and travel time conditions.
How is SIDRA Assign different from traditional traffic assignment?
Traditional assignment approaches generally rely on fixed routing assumptions determined before analysis. SIDRA Assign allows traffic distribution to respond dynamically to network performance conditions.
Why is SIDRA Assign important?
SIDRA Assign provides a more realistic representation of driver behaviour, particularly within larger or more complex road networks where multiple route options exist.
What types of projects benefit most from SIDRA Assign?
Projects involving multiple intersections, mixed-use developments, shopping centres, schools, transport infrastructure upgrades and broader network changes can particularly benefit from SIDRA Assign functionality.
Does SIDRA Assign replace engineering judgement?
No. Traffic modelling software remains a tool that supports professional analysis. Appropriate assumptions, calibration and interpretation by experienced traffic engineers remain essential.
Can Quantum Traffic assist with SIDRA modelling?
Yes. Quantum Traffic regularly undertakes SIDRA modelling, network analysis and operational traffic assessments for developments and infrastructure projects across Australia.
