A Round About Way in WA – AITPM

First and Foremost… Roundabouts

The AITPM WA AGM and technical session last week brought together an interesting panel of speakers and tackled a contentious topic. Main Roads WA prioritises roundabouts as the first preference for intersection design. Alternatives must be presented with a strong business case to be considered. With speakers from different departments at MRWA, local government, and a town planner, the discussion brought together varied perspectives making for an enlightening session.

An Urban Planning Perspective

When considering options for intersection design, the context should dictate the solution rather than trying to shoehorn a specific type of intersection based on a legislated mandate. This was the main takeaway from Tim Greenhill, of Urbis who opened the forum with an urban design perspective on intersection design.

Different land use contexts have varying degrees of importance in different situations. Adding a preferred intersection type makes the challenge of prioritising these contexts even more difficult. Roundabouts can cater well to motorised traffic but are inherently challenging for pedestrians with mixed abilities and cyclists. Tim’s example site, adjacent to aged care, child-care and rehabilitation facilities, highlighted a context where the design process shouldn’t be guided by trying making a roundabout work.


Why Preference Roundabouts

MRWA guidelines define the process for choosing an intersection control type.

In WA on the higher order roads, roundabouts are considered the most appropriate form of intersection control whereas traffic signals may be an appropriate form of control.

The rationale behind this position was presented by Dave Landmark from MRWA, who highlighted how it came about, and the evolution since inception.

KSI (killed or seriously injured) rates in WA are historically some of the worst in the country. The position to preference roundabouts was politically triggered to improve road safety and curb the rising road toll. This has been primarily driven by studies showing roundabouts provide significant safety benefits by slowing down traffic, reducing the number of conflict points and reducing the angle of potential conflict.

Signalising Roundabouts

Signalising roundabouts, particularly larger roundabouts, presented an opportunity to improve safety and also cater to other modes of transport. The reality of positioning signals, often a short distance before the intersection, isn’t always practical for pedestrians requiring a longer journey to cross the intersection safely.

Converging Ideas

The panelists all had different perspectives and background, however, there was plenty of common ground. While the big picture goals remain improving livability and moving people safely, the route to achieve these will continue to be refined.

Other Presentations

While not as controversial as the roundabout discussions, the other panelists presented on interesting developments including the project to optimise signal timing at all the intersections in the Perth region, treatments for self-explaining streets at an LGA level and the introduction of countdown flashing amber lights for pedestrian safety at intersections.

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