Johnsonville Safety Improvements — Business Case + Design

Overview

Wellington City Council engaged TTAP for the Johnsonville Safety Improvements project, addressing congestion, turning safety, speeding, zebra-crossing compliance and pedestrian / cyclist conflict in central Johnsonville. The brief covered business case through to post- construction monitoring.

What we did

Business case with options development, MCA, and engagement workshops
Traffic engineering and traffic-signal design — dual-lane signal intersection treatment
Civil design for short-list options including bus priority lane, southern and northern cycle lanes, cycle priority box, and improved Frank Johnson entrance
Modelling of the preferred option’s performance against demand forecasts
Communications and engagement with community and stakeholders
Post-construction monitoring to verify the safety case as built

Annotated aerial of the Johnsonville–Moorefield roundabout showing the short-listed interventions: northern and southern cycle lanes, a cycle priority box, dual-lane signal, bus priority lane, Frank Johnson entrance treatment, signage and lighting, and footpath improvement. — The short list, sited. Each option is placed on the intersection so trade-offs between cycle, bus and general traffic space are visible rather than abstract.

Outcome

The preferred option balanced safety improvement, mode shift, project alignment, emission reduction and community needs. The post- construction monitoring closed the loop on the business-case promises and gave WCC a defensible record of intervention effectiveness.

Engagement survey output showing the five top reasons people were concerned about the intersection — vehicle congestion during peak times, vehicles turning unsafely, vehicle speeding through the intersection, vehicles not stopping at the zebra crossing, and heavy activity on road and footpaths — alongside street-level photographs of the site. — What the community told us. The five concerns that shaped the problem statement, evidenced against site observation.

Team

Bob Hu (Managing Director / Principal Traffic Engineer) led the business-case workstream. Simon Cager (Principal Project Engineer) chaired traffic engineering and civil design. Stu Zhang (Transport Modeller / Assets Analyst) built the AIMSUN modelling that underpinned option evaluation. Charles Agate (Senior Assets Engineer / Traffic Management Specialist) led the traffic-signal design and post- construction monitoring. Ana Wang (Senior Project Manager) coordinated the workshop engagement and community-stakeholder strand.

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