Our Insights | Abley

Setting safe and appropriate speeds for our road networks

Written by Abley | Apr 2024

Our approach to speed recognises that what served us in the past is no longer fit for purpose as our traffic volumes and pressures on the network have evolved. Our approach needs to evolve too.

Recently Matthew Noon posted this blog on how speed limits are set, which generated some interesting comments and direct messages. Given the interest this article generated, here are some further thoughts on speed limits and what speeds our roads are designed for.

There was some feedback regarding the (perceived?) inconsistent application of speed management techniques between the national and local road networks. Although the issue has become politicised, we as road safety professionals also have a long way to go in communicating the importance of speed management. Not addressing it poses significant risk and cost to the community – which is measured not just in cost but people’s lives and wellbeing. How can we provide a more compelling narrative about why it is an issue that we, and the community and our politicians should support?

Much of the current discourse sees an ‘us vs them’ mentality. Parts of the community oppose better speed management because they think reduced speeds increase travel time (which in most cases is negligible) or impact on their personal freedom.

There were some excellent comments to my previous blog about the need to upgrade our road network. Indeed, it is a fundamental pillar of the Government’s adoption and commitment to the Safe System approach. The Safe System approach is based on four simple principles:

  • People make mistakes – crashes are inevitable, and nobody sees a zero-crash road system as realistic – in the short term, at least – but we don’t need to accept that death or serious injury is inevitable.
  • People are vulnerable – in the event of a crash at speed, the physics of mass and momentum mean we, as human bodies comprised of water, fat, muscle, and a little bit of bone, will come off second best. We need to understand that by controlling the crash forces as best as possible, they should be survivable – to quote Scotty, you cannae change the laws of physics.
  • It is everyone’s responsibility – while the Waka Kotahi advertisement “It takes everyone to get to no one” generated some mixed responses, the fundamental premise is correct. It is up to the road designers, builders, maintenance crews, vehicle certifiers, roading authorities, Police, and emergency services and ultimately us as individuals to do our part. We need to strengthen the whole system –improve our roads and roadsides, realise safe and appropriate speeds, ensure our vehicles are fit for purpose and ensure safe road use. This way, if any one part fails, the remainder of the system components will help protect us.
 

Similarly, the discussion about the merits of different speed limits and whether they should be 30, 50, 70, 90, or 60, 80 or 100km/h. We know drivers expect consistent speed limits and frequent variations are confusing, leading to less compliance. The focus on safe and appropriate speed is key to determining this consistency, and indeed, our setting of speed limit rules does allow for 70km/h & 90km/h but sees this as the exception to the rule rather than a default. The original point of my post was to recognise that as long the road is engineered correctly, we can go faster, e.g., 110km/h when we have the median and side barriers and other features to catch us if something goes wrong – high speed tyre blowout perhaps? However, the thin white line is no protection on most of our roads.

That said, engineering our way out of the problem is not feasible or affordable. While putting more money into our transport network will always be beneficial, there may be better places to direct our limited public funds. Like most things, it’s about getting the balance right.

As to how 100km/h limits may have served us well in the past,  remember that it was only put up from 80km/h in the mid-1980s. However, in the last 20 years alone, the total vehicle kilometres travelled on our roads have increased by over 25% to over 43.5 billion kilometres. Our approach to speed recognises that what served us in the past is no longer fit for purpose as our traffic volumes and pressures on the network have evolved. Our approach needs to evolve too. The data also clearly shows that our road toll increased – irrespective of volumes when the speed limit increased from 80 to 100km/h.

The faster you go, the bigger the mess.

As a final thought, here is the fatality rate per 100,000 population across 36 OECD countries (source: Australian Government).

Looking at this, the level of fatalities on our roads is unacceptable. As a country, we generally pride ourselves on performing better than other countries – our poor ranking is not something to be proud of. We should and must, do better.

Thanks all for the comments, and while this discussion will undoubtedly continue well into the future, we need to keep focused on the end goal – ensuring that we keep reducing the number of our family members, friends, neighbours, and colleagues from injuring themselves or dying on our roads.