Humans make mistakes: why we can’t abandon this core Safe System principle

By Dr Amy Williamson

Technical Lead – Safe People | Safe System Solutions

In recent years, a slight philosophical division appears to have emerged among road safety professionals about how the human element is addressed in road safety.

The 2024 ACRS policy position paper on a new systems thinking approach to road safety proposes a shift away from core Safe System philosophy – specifically, the principle that we accept inevitability when it comes to human error – and instead (or at least place greater focus) on preventing human error and its consequences.

The Safe System approach accepts human fallibility and therefore focuses on designing a system that does still involve encouraging safe behaviour (and reducing human error to an extent) – but ultimately reduces the exposure and likelihood of a crash, as well as the severity of crashes when they do occur. This represents a shift from the historical focus on improving road user behaviour to improving the system and making it more forgiving as a whole.

Systems thinking theory has been widely applied in other domains such as aviation and work health and safety. The very brief premise of this approach is that safety arises from the interactions between multiple components of a system, and that we can manage risk by addressing system level factors to reduce the circumstances which lead to serious crashes and increase the circumstances which prevent serious injury.
Systems thinking offers immense value to road safety, however, I question the rationale for it moving us away from the core premise of Safe System, and that we, as practitioners, can place this level of focus on the prevention of human error in the land transport system.

Is the Safe System approach failing?

Those who are proposing the shift appear to base their argument on the premise that the Safe System approach is failing, and we need to do something else. The Safe System approach is evidence based. It just hasn’t been delivered to its full potential – or at the pace needed.

That aside, when Safe System interventions such as median barriers and raised safety platforms are implemented, and interventions such as speed management are integrated, we’re seeing huge success! Imagine if we could deliver Safe System interventions in an integrated and coordinated way, with the right leadership and accountability? System leadership is a key component of the Safe System approach.

System thinking approaches can help us identify the network of system level factors that impact the emergence of harm, and our ability to deliver Safe System wide interventions, including those that protect people after an error has occurred. Factors such as culture, government policy, regulation, operational practices, as well as individual and psycho-social factors all need consideration and require those of us in road safety to understand the bigger picture when interventions are designed and delivered.

Understanding this network of system wide factors could greatly assist our efforts to strengthen our system leadership (and in doing so better define shared responsibility) – arguably the missing piece of the puzzle to enabling successful Safe System delivery – and one that is now widely acknowledged by jurisdictions and with some fantastic work by international road safety bodies underway, including Austroads. While the term pillar may still linger in our language at times, I think we’ve moved on from them being considered isolated areas of intervention. The current advancements in the system leadership space will help us immensely to deliver a Safe System in a coordinated way.

The inevitability of human error

The other aspect to all of this relates to the notion of whether we should accept human fallibility/error (and therefore place importance on being risk-based and harm-focused) or reject the inevitability of human error and place greater focus on preventing error and resulting crashes. This is a monumental task.

In other domains, I can understand why this would be the way to go. In aviation – the goal has to be the prevention of a near miss at all costs. But it’s a different risk appetite conversation – the types and levels of risk are different. All levels of control need to be put in place to prevent human error. From a regulatory perspective, this relates to what types and levels of risk we are willing to tolerate and therefore how to prioritise resources and pull the right levers at the right time to prevent harm.

But is it appropriate – or even practical – in road safety overall? The land transport system is unique compared to aviation, for example. We’re not talking about highly trained specialist pilots who operate in highly automated and a much more controlled environment. The land transport system is different. It involves people of all ages and demographics, it involves different types of road users and vehicles who all have to co-exist, it involves people with different needs and with varying levels of experience and capability, it’s intricately linked to other systems and has many varied influences. We use the land transport system to get around in our busy and chaotic lives where we have children and pets in the back, we have to-do-lists circling around in our heads, we deal with emotion and stress, we have momentary lapses in attention and judgement, and all these things are going on as we’re trying to navigate an already complex and dynamic system where the consequences of error can be very severe. Isn’t human “error” just part of our humanness?

We can do lots of things to encourage safe behaviour and reduce human error – and I agree we could be doing more (including in how we reduce exposure) but I do not believe we can achieve a Safe System by overly focusing on the prevention of error – there are too many factors at play. We can’t expect practitioners to address each and every one of them so that an error doesn’t play out and lead to harm. We need to accept a level of inevitability in human error (or our humanness) and reduce the likelihood, exposure and severity of harm, which is what the Safe System is designed to do.

I don’t think anyone is disagreeing that we make errors as humans – it’s what we decide to do about it through our approach to road safety. I think there are opportunities to apply systems thinking to do more to improve road safety practices and prevent error (including in the work-related road safety space) – but there are also unconscious processes at play that contribute to human error even with the best conscious intentions of drivers. I think it would be counter-productive to expect road safety professionals (even as we improve our system leadership) to try and address the array of factors including those unconscious processes that can result in error.

Road safety isn’t black and white

In my time as a road safety researcher and practitioner, I’ve often heard people say “engineering can’t fix everything” and that we need to focus more on the behavioural space. However, I don’t think it’s that black and white. We need to improve our infrastructure and road design and manage speeds to minimise the likelihood and exposure of crashes as well as the severity when the countless number of factors that can lead to human error results in a crash.

Even when we introduce other Safe System interventions in the vehicle space such as safety technology, I don’t believe that we can ever completely remove the human element as we also sometimes hear – on the same practical grounds. We will always need to encourage safe choices and behaviour and do what we can to reduce human error – and there are opportunities to do so much more in this space (beyond enforcement, education, training) – particularly in how we look at reducing exposure among vulnerable road users, as well as in how to prevent high risk (and repeat) behaviour.

A more holistic system approach

What if we took a more joined up road safety/public health approach to intervene earlier and in doing so prevent high risk behaviour? What if we took a more joined up road safety/community approach so that people without a driver’s license or who might be on prescription medications could still get to their doctor’s appointments and visit their families safely? What if we had better public transport or alternative transport options to make it easier for people to get home safely after a rugby game? This is where I see systems thinking approaches really helping us in being able to take a more holistic “whole-of-system” view of the Safe System. This could also enable more equitable road safety outcomes for all road users. I agree that the concept of usability should be a central design principle in road safety (as proposed in the ACRS position paper) – and that we can think more holistically about this across the Safe System.

As mentioned earlier – I see these approaches helping us in work-related road safety, too. There are opportunities to do more to strengthen the overlap between road safety and WHS contexts – and take action further upstream by strengthening regulation, policy and other factors to prevent high risk behaviours and errors relating to fatigue, distraction, alcohol and speeding. There are opportunities to do this in a work-related road safety context – where those driving for work are enabled to be safer on the roads.

Bridging the divide

More generally, we can’t prevent human error among all road users as a strategy to prevent deaths and serious injuries. I think the two schools of thought in this space both have much to contribute – and we could bring this thinking together to create a Safe System free from harm. I’m offering my perspective as someone who has worked in road safety for a number of years in both academic and government roles.

I do wonder if it questions how we conceptualise and define “human error” in the Safe System. Do we need to revisit our definition of “human error” vs “risk taking”, for example? (A dichotomy that we seem to rely on a lot in the Safe System). Are things like drink and drug driving, fatigue, seat belt use, distraction, even speeding, “contributing factors” in and of themselves, or are there wider system level factors that can be better understood and addressed so that these traditional road safety problems are dealt with earlier on and thus in a more preventative way. Do we think about “human error” through an overly driver-centric lens in road safety and need to accept that “error” is often just part of us being human and that as road users of the land transport system we have different capabilities and capacities that must be accounted and designed for.

I think systems thinking can help with this, but I don’t believe it warrants rejecting the principle of human error as an inevitability in our approach to road safety.