How can cities and transportation agencies make faster, smarter, and more data-driven decisions about roundabout design and infrastructure planning?
Our recent webinar “SIDRA – TORUS Integration: Transforming Roundabout Design and Analysis” was co-hosted by guest speaker Mark Besley, Scientist and Software Developer from SIDRA SOLUTIONS, and Janz Arqueza, P.Eng, Transportation Engineer from Transoft Solutions. This session explored how the new integration between SIDRA INTERSECTION, a traffic capacity and performance analysis solution from SIDRA SOLUTIONS, and TORUS, a roundabout design solution from Transoft Solutions helps engineers streamline workflows, reduce errors, and help make informed, data-driven decisions for roundabout design and analysis.
Figure 1: Importing SIDRA-generated Capacity analysis results to TORUS
Key Themes from the Webinar
- Key features of SIDRA INTERSECTION roundabout analysis in Version 10 and additional capabilities of SIDRA compared to Highway Capacity Manual (HCM)
SIDRA INTERSECTION Version 10 offers enhanced lane-based multimodal traffic modelling, improving capacity and performance calculations. It offers expanded support for assessing the effect of nearby intersections, pedestrian crossings, and roundabout corridors. Compared to HCM, SIDRA offers more granular control of parameters, richer performance outputs, and stronger tools for assessing operational efficiency under varied demand and intersection geometry conditions. - Unified Workflows: Geometry and Traffic Analysis in One Pipeline
Traditionally, designing a roundabout and evaluating its performance were separate steps: geometry design in one tool, capacity analysis in another — often requiring manual data transfers and repetitive parameter entry. The integration allows seamless handoffs:- From SIDRA to TORUS: Import existing SIDRA files directly into TORUS to build your roundabout geometric design with insights from pre-existing traffic analysis data. This saves time and reduces errors from manual re-entry in TORUS.
- From TORUS to SIDRA: Generate clear traffic data reports from your geometry design in TORUS, then export them directly into SIDRA INTERSECTION via SIDRA project files (.sipx) for detailed checks and refinements.
The benefits are clear: Less time on manual data entry and calculations, more time on design refinement and validation. Faster project delivery without compromising quality or accuracy.
- Faster Iterations and Reduced Design Time
With the integrated workflows, teams can iterate multiple design alternatives in a fraction of the time. You can tweak entry lane and circulating lane geometry, entry/exit configurations, or splitter island layout in TORUS, export to SIDRA, and immediately review operational metrics — all without re-drawing or re-entering geometry data manually. This not only accelerates the iterative workflow process but also supports more ambitious exploration of alternative designs early on. - Evidence-Based, Defensible Design Decisions
To build a safe and efficient roundabout, backing design decisions with data is crucial. By integrating SIDRA’s lane-based capacity modeling and performance analysis with TORUS’ geometric precision, civil engineers can produce documentation that demonstrates how a roundabout will perform under projected traffic demand. This reduces reliance on assumptions and supports transparent, defensible decision-making. - Safety, Compliance, and Versatility of Roundabout Designs
TORUS brings built-in design guidelines, vehicle swept-path modelling, and dynamic compliance checks for roundabout geometry that supports everything from single-lane roundabouts to complex multi-lane and non-circular configurations. When combined with SIDRA’s ability to simulate multi-class traffic (light vehicles, heavy vehicles, buses, bicycles, etc.) and provide level-of-service, delay, queue, and emissions outputs, this integration ensures that your designs are not only geometrically appropriate for safe operations but also efficient, and adaptable to various traffic mixes. - Reduced Risk of Late-Stage Redesigns and Review Delays
Often, capacity or performance concerns are identified only after detailed geometry is finalized, leading to costly redesigns, delays, or compromises. With the integrated TORUS–SIDRA use, performance evaluation becomes part of the initial design process, allowing issues to be identified and resolved early. This proactive approach reduces project risk and helps ensure that final designs are viable, compliant, and ready for construction.
Figure 2: A traffic impact assessment example using SIDRA INTERSECTION 10
Why This Matters
In an environment where roundabouts must satisfy safety standards, traffic demand, multimodal accommodations, as well as project budget and schedule constraints, having a toolchain that connects design and analysis is critical. The TORUS–SIDRA integration delivers that connection, enabling engineers to generate geometric design and immediately evaluate performance that make design decisions founded on data rather than guesswork. This leads to more efficient and future-ready roundabout designs, with less rework, greater confidence, and more defensible submissions to stakeholders and approval bodies.
Key Takeaways
- Design with traffic perfermance in mind: Bringing pre-existing traffic data from SIDRA to TORUS to generate your geometry designs ensures your roundabouts are built based on real-world traffic insights, not assumptions.
- Iterate early, iterate often: A faster feedback loop between design and analysis helps teams refine layouts before issues become costly.
- Back decisions with data, not intuition: Lane-based capacity modelling and measurable performance metrics strengthen the defensibility of design recommendations.
- Prioritize safety and road user needs: Integrating geometric standards with multimodal traffic analysis supports safer, more inclusive roundabout designs for all users.
- Reduce risk through integration: Catching performance challenges early minimizes late-stage redesigns and accelerates smoother project delivery.
To watch the on-demand webinar, please watch it here.
To learn more about TORUS, you can visit our product page, and to learn more about SIDRA INTERSECTION, you can visit the product page.