It's an issue that bitterly divides Kiwi motorists into competing lanes of thought - and apparently the authorities too.
Is it reasonable for drivers to travel at 100km/h in the right-hand lane of a highway if there are cars behind you wanting to pass?
Should you move into a left lane, despite travelling at the full legal speed limit, to allow motorists who want to travel over the speed limit to do so?
Confusion over the road law is being thrashed out on the airwaves and online as a court case over driver culpability in a fatal accident in Upper Hutt continues.
Two cars met in one lane on a notorious stretch of State Highway 2 just past Gibbons St intersection the morning of November 14, 2020. Both cars were driving at approximately 103km/h side by side before colliding as the merging lane ended. The judge in the case is expected to deliver his reserved decision at the end of the month.
While unwilling to comment on the Upper Hutt case, the New Zealand Police insist speed limits are to be adhered to - regardless of circumstance.
"Police understand the frustration caused by slower drivers who speed up when entering passing lanes, but this does not create an excuse or mandate for exceeding the posted speed limit," the NZ Police website says.
"While police take a more pragmatic approach when enforcing speed on passing lanes, the few seconds saved passing an irritating vehicle are simply not worth the risk."
A police spokesperson backed up this official messaging to the Herald this week when asked about speed limits in the right lane of highways.
"The speed limit is the speed limit. Any road user who is travelling over the speed limit can expect to be stopped," the police spokesperson said.
However, according to the Automobile Association's driving school's general manager, Roger Venn, the road code is "crystal clear" that the speed limit is not a determining factor in who is in the right when travelling in the right-most lane.
"The speed limit is irrelevant in this context - the driver is not the enforcement agent," Venn said.
"If you have finished passing slower vehicles on the left, you simply return to the left or nearside lanes, lane 1, as soon as it is safe to do - leaving the outer lanes, lane 2 or 3 if applicable, free for other traffic to pass you."
While a distinction between a three-lane metropolitan highway and a temporary overtaking lane on a one-lane rural highway should be made in the fatal Upper Hutt accident, the road code applies equally in both circumstances.
Venn said passing in a left lane is "inherently more dangerous" as it involves a much larger blind spot for the vehicle you are passing - which should also theoretically be moving left directly into where you are at some point.
"Staying in the outer lane or lanes when you could return to the nearside lanes also means you are closer to oncoming traffic and head-on risk (even if barriers are present) - again increasing risk," Venn said.
"Just 'sitting' in the outer lane at 100km/h, or whatever the posted limit is, is not acceptable - assuming the inner lanes are free. It can be incredibly frustrating for other traffic and shows a lack of etiquette and awareness - key attributes all safe and competent drivers should hold."
Venn said the question of whether it is reasonable to sit in the right-most lane travelling at the speed limit is a common one among AA members and within his driving instructor network.
The relative confusion of Kiwi motorists, and their corresponding erratic driving on New Zealand highways, contributes to a far worse road toll than in countries of equivalent population.
"Some of the safest roads travelled in the world per kilometre travelled are European autobahns and motorways - some of which have no speed limit. And guess what - the keep left or simply 'return to lane 1 when safe to do so' (rule) is adhered to almost without question - the attitude is far more mature - faster traffic is just simply allowed to pass safety on the outer lanes," Venn said.
"The UK also has a very safe motorway network with speed limits higher than NZ's and also adheres very much to the keep left mantra - a simple flash of the lights from an upcoming faster vehicle from behind is generally viewed as a courtesy notice to move left so they can pass - in NZ in my experience this course of action is invariably either ignored or deemed an act of aggression."
The Auckland Road Safety Business Improvement Review 2021 found that if New Zealand's road safety conditions matched the state of Victoria in Australia - which has a population of around six million - approximately 124 fewer New Zealanders would have died on our roads in each of the last three years.
New Zealand's road fatalities per billion vehicle kilometres travelled also rated incredibly poorly in the International Transport Forum Road Safety Report 2020.
New Zealand averaged just under eight road deaths per billion km - worse than more than 15 European countries and the US.
In comparison, Australia averaged just over four road deaths per billion kilometres. Denmark, a similar-sized country to New Zealand, registered around three road deaths per billion vehicle kilometres travelled.
Motor vehicle crash investigator Hamish Piercy said stubborn motorists remaining in the right-hand lane of highways when there are drivers wanting to pass was endemic of a lack of manners on Kiwi roads.
Piercy said authorities such as Waka Kotahi NZ Transport Agency (NZTA) and Auckland Transport are overly preoccupied with advertisements and messaging around speeding but fail to reinforce driver courtesy, manners and common sense while on our roads.
"We could also have better advertisements. I mean we see lots of advertising from NZTA Waka Kotahi media, talking about speed. To be honest, speed isn't the issue we've had over years past. Speed is a factor in every crash but when we look at, it's driver behaviour," Piercy said.
"Now when was the last time we saw advertisements instructing people how do drive safely, and how to drive properly?
"So, for example, lane use on highways. How often do we see slow drivers in the right hand lane? They might think they're doing the speed limit, and even if they are doing the speed limit, if they're not overtaking, use the left lane."
Piercy also highlighted that speedometers "aren't necessarily accurate" and you may be travelling several kilometres under 100km/h, despite it appearing that you are on your dashboard.
The issue has also generated some vehement responses online from random Kiwi motorists.
Aucklander Geoff Upson has set up a Facebook page describing himself as a 'Road Safety Campaigner' with more than 4000 followers, from which he posts numerous videos of motorists wrongly remaining in the right-hand lane.
One video Upson posted this week is entitled: "Super frustrating! Why can't the New Zealand Police enforce the keep left unless passing law?"
In it, Upson can be seen approaching a red hatchback travelling slowly relative to other traffic in the right lane of a three-lane highway.
Approaching it, Upson tails the hatchback while other cars pass the pair of vehicles travelling slowly in the right hand lane.
The 160 comments to the video demonstrate the division that exists among Kiwi motorists on the etiquette and rules around travelling in the right lane of highways.
One commenter in support of Upson posts: "See this every day on the roads... so frustrating. Road code says keep left at all times unless overtaking."
Yet many others advocate for overtaking in a left lane, including this: "The keep left unless passing is for highways not motorways. You've got multiple lanes to choose from so pick another, go around them."
Upson is also behind a parallel online campaign entitled Better Roads In New Zealand which advocates for the return of highways to 100kmh instead of the widespread reduction to 80km/h on many of NZ's highways.
"Reducing speed limits is an absolute joke and wont (sic) teach incompetent drivers the basics," it says on the BRINZ website.
The right lane highway debate also caused a flurry of impassioned responses on Newstalk ZB, after presenter Andrew Dickens expressed his irritation at having people trying to pass him when he's travelling at the 100km/h speed limit in the right-hand lane.
"If I was doing 100kmh in the right lane I am not breaking the law. I am going the fastest you're allowed by law. It is advised that you should move to the left. If you undertake me at 110kmh you're breaking the law. Got it? Good Lord!" Dickens said on air.
Dickens was responding to listener messages into the station disputing his point of view.
"Not using the left lane, sounds like you're the problem Andrew," one listener messaged in.
"Doesn't matter what speed you're going Andrew, if you're in the right lane you move over for faster traffic," another texted.
NZTA is the official authority on the road code and highlighted the same section of the code as AA's Roger Venn did:
The lane closest to the centre line should only be used when: • you want to pass another vehicle • you want to turn right • the left-hand lane is full with other traffic or is blocked.
An NZTA spokesperson added: "If the traffic is free flowing on a multi-laned motorway, no one should be just driving in the lane closest to the centre line. The right-hand lane should only be used in the specific circumstances outlined as per the NZ Road Code".
However, despite NZ Police's seemingly convergent messaging on the issue by emphasising adherence to the speed limit above all other considerations, a police spokesperson did highlight the ability of road enforcement officers to use their discretion in fining motorists.
"Our frontline officers have always had the ability to use discretion, this means our staff will speak with the driver and decide what action is taken. It may be education, compliance, or enforcement, depending on the circumstances presented," the police spokesperson said.
But the police were ultimately unapologetic in making reducing speed their primary focus in road safety messaging. Road etiquette and rules of the road code were not mentioned.
"For every 1km/h reduction in mean speed across the roading network, there is a 6 per cent reduction in fatal crash risk. At the current rate of deaths on our roads, this could equate to 18 lives saved a year," the police spokesperson said.
"We know that speed has the greatest impact on the outcome of a crash - whether you walk away, or are carried away. That is why we continue to focus unapologetically on speed."