Dear New Zealand Transport Agency,

I'm writing to ask for clarification around the behaviour of traffic lights in NZ. There are many intersections where both a red left arrow and a red disc appear on a single light post fixture that is fully populated with 6 bulbs, 3 per aspect. At some times, both the red arrow and red disc are lit. What I'd like clarification about is why there are times that these same fixtures sometimes display a red disc but have the arrow aspect completely unlit. This happens after the disc and arrow go from green to yellow - while the disc turns red, the arrow turns off. Shortly after, the left arrow turns green again when left turning traffic is protected by right turning traffic entering the intersection from the traffic entering the intersection perpendicularly to the left.

Given the above explanation, my questions are as follows:

1. What is the correct course of action for a driver in a controlled left turning lane in this scenario?

2. Why was this implementation chosen over explicitly making the left arrow red before turning it green again instead of having it unlit briefly? What safety and psychological considerations/assessments have been made regarding this? Is this implementation the result of a technological limitation, a standard operating procedure, or something else?

4. Is or was this situation documented on your website? If so, where? When was this first and/or last present?

5. Is or was this situation documented in the road code book? If so, where? When was this first and/or last present?

6. Is or was this situation documented in law? If so, where? When was this first and/or last present?

Please omit any information you do not hold and answer what you can. If you do not hold the information, please advise who you suppose does, where applicable. Thank you for your time.

Yours faithfully,
Emilia Sharp