Technology Update

A Safe Roundabout

The new TORUS Roundabout software from Transoft is helping engineers to slash roundabout design.

The new TORUS Roundabout software from Transoft is helping engineers to slash roundabout design. Any design engineer tasked with the job of designing a roundabout would appreciate the intricacies of this junction type.

Steven Chan, Director of Product Management for Transoft Solutions, certainly understands the challenging steps it takes to put forward a safe and functional roundabout.

“Designing roundabouts involve a very integrative and iterative process,” he says. “As a designer you need to balance the geometry, as every small change has a direct impact on safety.”

While a few design considerations are fairly straightforward – for instance whether a design will be single or double-lane – he says engineers have traditionally spent hours on the finer intricacies of defining the geometric shape. As they change a single leg of the layout, they need to re-perform calculations to check the functionality of the full design.

It was this appreciation of the complexities of roundabout design that has led to the launch of TORUS Roundabout 5.0, the latest roundabout software from Transoft.

As the company name implies, Transoft is a software company dedicated to transportation software, allowing the group to develop a niche specialty for the needs of transportation engineers. The result is software like TORUS that features intuitive built-in features that can save a designer weeks of work.

One of Transoft’s main claims to fame is its AutoTURN software. Used by government agencies, engineering consultants and transportation design professionals the world over, AutoTURN swept path analysis is trusted for its ability to measure a vehicle’s off-tracking: that is, the movement of both the front and rear wheels.

Mr. Chan explains that what really sets the latest models of TORUS apart is its full integration with AutoTURN.

Previously, designers would need to run their roundabout designs with AutoTURN to check their models. “We conceptualised the first version of TORUS based on a lot of requests from our AutoTURN users,” he says.

TORUS Roundabout software includes full integration with AutoTURN. Designers can automatically check vehicle swept paths as they adjust their designs.

With this integration, TORUS allows users to check the function of their roundabouts according to different vehicles, or a set of vehicles. For instance, a design may need to satisfy fire truck manoeuvres for the 180-degree turn while ensuring wider lane widths for oversized trucks for the right and left turns. .

“Simply based on the chosen design vehicle for the site, TORUS will use the built-in swept path analysis to figure out how much space is required at the entry, circulatory, and exit points,” says Mr. Chan. “With every modification like repositioning the roundabout or changing the size of the inscribed diameter, the software will automatically adjust the roundabout geometries to ensue sufficient lane widths.”

TORUS 5.0 also features an integrated 3D grading modelling system. Throughout the design process, a user can run the grading model to consider the 3D impacts of their designs and estimate the full footprint. In conjunction with AutoTURN Pro 3D, the grading design can be checked to determine if low ground clearance trucks, such as low loaders and drop deck trailers, would scrape against the ground as the rear wheels mount on the truck aprons.

For designers using 3D platforms such as Autodesk AutoCad or Bentley Microstation, TORUS is integrated with those programs.

“Because our tool works the same way in both platforms, designers only need to learn our tool once and be able to take on projects on either platforms,” he says.

That being said, Mr. Chan highlights that – as with all Transoft software – the program is fairly intuitive and easy to learn.

Designers also appreciate TORUS’s ability to provide sight-line analysis of roundabouts. The software can calculate sight-lines according to stopping sight distances and intersection sight distances. The feedback would graphically illustrate whether sufficient sight distance is provided.

When it comes to calculating vehicle speed, TORUS offers designers a highly integrated tool. The fastest path analysis tool calculates the highest speed a vehicle could be entering the roundabout, based on its geometry. Not only does it analyse the entry curvatures, it also considers acceleration and deceleration rates.

TORUS is finding a niche not only in designing roundabout geometries, but also performing safety checks on roundabouts not designed with TORUS. The developers have innovated a method to help designers check existing roundabouts. Given a design concept or an existing constructed roundabout, TORUS can help estimate which vehicles can make it through as well as determine the highest speed in which a vehicle could negotiate the roundabout. “With this technology, designers are equipped to perform checks on their designs or reviewing other designs,” says Mr. Chan. “This helps ensure that quality roundabouts make our community safer.”

Although TORUS has proved an industry favourite, Mr. Chan says that the team at Transoft is still dedicated to continually improving its software. From their latest research, Transoft have advanced TORUS to develop turbo roundabout designs. Officially introduced in the Netherlands in 2000, the turbo roundabout is emerging as a safer alternative to the conventional multi-lane roundabout. “With more complex geometric design involving nested spiral lanes, it was a perfect problem for TORUS 5 to solve,” says Mr. Chan.

Although the software was developed in North America, Mr. Chan notes that TORUS is fully compliant with Austroads’ standards.

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