Traffic signals

Designing or reviewing traffic signals is a specialist discipline. As well as considering the practical and legal implications of different signal phasing options, there is a need to ensure that the layout, design and operation meets the safety and efficiency needs of all types of users through the intersection.

Collectively, ViaStrada staff have designed, reviewed, audited, or optimised hundreds of signalised intersections. As consultants, we work on behalf of central government agencies, road controlling authorities, and developers.

We were involved in the country-wide audit of signalised intersections in the early 2000s (we audited in Dunedin and Tauranga) and then compiled the main findings in a booklet Stops and Goes of Traffic Signals (as of 2024, an update is being worked on).

We have produced the following publications:

• Green Lights for Bikes (2010)
• Stops and Goes of Traffic Signals (2004; republished in 2006)

We have also developed the guidance for cycle and pedestrian treatments at traffic signals that has been incorporated into the NZTA's Cycling Network Guidance and the Pedestrian Network Guidance. This guidance also forms part of our industry training courses for walking and cycling; Axel Downard-Wilke and Glen Koorey also regularly taught traffic signal design and operations to engineering students at Canterbury University. ViaStrada are the exclusive resellers and trainers for SIDRA Intersection software in New Zealand, used for assessing all types of intersections.

Projects for developers include:

• signalise the Smith / Tunas intersection in Kaiapoi and create a fourth leg (2024)
• design signalised mid-block crossing for a new high school at Northcote Road, Christchurch (2023)
• safety audit traffic signals for large residential subdivision (2012, 2018, 2019)
• safety audit traffic signals at the Noble Village subdivision (2010)
• signalise the Clarence / Dilworth intersection in Christchurch (2009)
• signalise access to Bunnings on Marshland Road (2008)
• modify the Kawarau Falls single lane bridge signals for access to the Kawarau Falls project (2007)

Projects for local authorities include:

• signalise Devon Street West / Lorna Street T-intersection, New Plymouth (2024)
• redesign Devon Street West / Morley Street intersection, New Plymouth (construction in late 2024)
• relocate and redesign mid-block signals in Glenview, Hamilton (2023)
• Meeanee / Murphy intersection concept and detailed design, Napier (2023)
• design mid-block signals in Inglewood, Taranaki (2022)
• Guppy / Meeanee intersection detailed design, Napier (not yet built)
• design or retrofit five sets of signalised intersections for the Te Tuaiwi pathway, Whanganui (2018–2020)
• upgrade one signalised intersection per year for Whanganui District (since 2019)
• Marshland / Lower Styx / Hawkins audit (2016–2017)
• Bealey / Madras audit (2016–2017)
• Halswell Road audit (2016)
• traffic signals as part of the Palmerston North Junior Road Safety Park (2014)
• Main North Road optimisation (2013)
• 13 signalised intersections along Te Okuroa Drive, Tauranga (2008)

Research projects (and proposals) include:

• low-level cycle signals (2024 onwards)
• separated cycleways and filter turning (2023 onwards)
• directional cycle signals (2018–2019)
• filter turning across cycleways (2018)
• separated bicycle facilities: legal issues (2014)
• cyclist delay at traffic signals (2014)
• red light camera peer review (2011)
• pedestrian level of service at traffic signals (2010)
• traffic signal compliance and call accept (video; 2010)
• concept development for staged pedestrian crossings (2008)
• policy development for right turn protection (2008)
• hook turns for cyclists (2007)
• modelling of congested offset signalised T-intersection (2006)
• cycle paths at signalised cross intersections (2005)
• cyclists at wide intersections (2001)

Our staff member Megan Gregory went on a study tour to North America in 2016 to research ways of addressing the conflicting movements of bicyclists and motorists at signalised intersections involving protected bike lanes.

Our staff have won several awards in relation to traffic signals:

• Best Research Paper award for "directional cycle signals" (2019 NZ Transportation Conference)
• study award from the IPENZ Transportation Group for Megan Fowler (2016 IPENZ Transportation Study Award)
• Best Technical Presentation award for "Legal Issues for Separated Bike Facilities" (2014 SNUG Workshop)
• Best Young Author award for "Staged Pedestrian Crossings" (2008 IPENZ Transportation Conference)

For further information and advice regarding traffic signals, contact Axel Downard-Wilke. For detailed design of traffic signals and controller software, we collaborate with Bill Sissons of Advanced Traffic Solutions. More information can also be found in the PDF brochure below.