Many New Zealand roads, particularly in cities with historic layouts, weren’t built for today’s large vehicles. Winding, narrow and often steep, these former horse-and-cart tracks are now essential routes for public transport. So what happens when a bus simply can’t stay within its lane?
Under New Zealand road rules, all drivers must:
Keep as far left as practicable within their lane
Drive at a speed that allows them to stop safely within the visible distance ahead
Stay in their lane and avoid crossing into oncoming lanes unless overtaking safely
The rule is simple: stay in your lane. But roads aren’t always simple, and sometimes the size of a vehicle like a bus makes that physically impossible.
When It’s Legal to Cross the Centre Line
There is a legal exception that applies to larger vehicles, such as buses. A driver may cross the centre line if:
It’s impractical to stay fully in the left lane due to the size of the vehicle
The manoeuvre can be done safely and without obstructing or impeding other road users
In short, the law recognises that buses and other large vehicles occasionally need more room. But the key is doing so with caution and minimal disruption.
How Drivers Should Approach It
In real world driving, these moments come up quickly. If a bus needs to swing out over the centre line, for example on a tight bend or around a parked car, the driver must:
Assess if the move can be done safely, especially on blind corners
Slow down significantly to remain in full control
Cross only as much of the centre line as needed, typically just enough for the rear axle to clear the inside of the corner
Return to the correct lane as soon as possible
It is not acceptable to take wide corners simply for speed or comfort. The goal is always to minimise time in the oncoming lane and avoid putting other drivers at risk.
This is where things can get tricky. The law uses the phrase “safely and without impeding other traffic” but does not provide a strict definition. That makes it a judgement call, often made in the moment by the driver and potentially reassessed later by Police or in Court.
Even if a driver believes they acted safely, an officer might reach a different conclusion. That means there is always a chance of receiving an infringement or being charged, even when following best practices.
The best defence is a consistent commitment to safe, responsible driving. That means:
Training your drivers to understand the law and assess tight-road situations carefully
Reinforcing the importance of slowing down, checking visibility, and minimising time across the line
Documenting procedures and incidents where legal exceptions are used
This isn’t about finding loopholes. It’s about professional judgement, public safety and operating in good faith.
At Gibson Sheat, we specialise in legal matters across the road transport sector. Whether you have questions about the content of this article or broader concerns affecting your operations, our team is ready to support you with clear, practical advice.
Craig Tatley offers a rare and valuable perspective in this space. As both a solicitor in our litigation team and a regular urban bus driver in Wellington, he understands the legal and operational challenges faced by those on the road every day. His experience allows us to provide guidance that is not only legally sound but grounded in the realities of passenger transport in New Zealand.