A draft letter outlined how the crossing could be confusing for motorists and pedestrians determining right of way because it looked like a pedestrian crossing.
"There is a high risk of confusion and a dazzling and distracting effect."
WCC went ahead with the crossing anyway, without an exemption to the Land Transport Rules NZTA considered it to be in breach of.
A year on from when the road turned purple, blue, green, yellow, orange, and red, WCC has still not formally applied for an exemption.
Documents released under the Official Information Act show in January WCC sent a monitoring data summary to NZTA saying the crossing had not created or increased any negative safety risks to pedestrians.
It also noted the installation of a speed cushion had created larger gaps and slower speed in traffic flow.
Chief city planner David Chick said given this, he looked forward to the formal exemption at NZTA's "earliest convenience".
But NZTA officials wanted a copy of that data to see for themselves. WCC eventually handed it over in July.
The data was given to an NZTA analyst who came back painting a very different picture.
His summary, in simple terms, was that the chance of someone crossing on a red light had doubled.
The analysis painted a "sea of red" showing reduction in compliance across the board. Officials also noted no evidence had been provided that speed and gaps in traffic had changed.
In August NZTA sent a letter asking WCC to formally apply for an exemption and attached a copy of its analysis.
It said the crossing was in breach of the Land Transport Rules because pedestrian crossings must be prescriptive and must not be in an area controlled by traffic lights.
In granting an exemption NZTA has to be satisfied the risk to safety will not be significantly increased.
NZTA safety, health and environment general manager Greg Lazzaro said they were yet to form a final view as to whether an exemption could be granted.
"We would welcome any further information you can provide us to help us with that assessment."
A WCC spokesman confirmed the council had received the letter and was in ongoing discussions with NZTA over the crossing.
"We'd rather not comment further except to say we've kept a very close eye on the crossing in the past year and there have been no incidents on it that have given the council cause for concern about safety."