This is a guest post by Glen Koorey from ViaStrada.
Do you know how many fatal or injury road crashes there were in 2018? No, neither did I, until I looked it up. Turns out there were 11,433 injury crashes, of which 2085 had serious (hospitalising) injuries and 332 had fatalities.
Why don’t most people know that? Because most of the public media attention revolves around the number of road deaths every year. So, it’s not surprising that many people know that this figure was 378 deaths in 2018 (or could guess something similar), although fewer might know that there was also over 2500 serious injuries that year. Either way, clearly we’d rather not have over 2900 people killed or seriously injured each year and that is the focus of our transport agencies’ road safety efforts.
Despite this, a lot of the public debate around road safety seems to end up with people suggesting various ways to reduce crashes. But this is not the same as thinking about how to reduce deaths and injuries. Obviously, there is some correlation; you have to have a crash first to have an injury of some sort. But if you’re trying to focus on how to reduce the latter most effectively, you will come up with quite different solutions from trying to reduce crashes the most.
An example might help explain this better: Consider “rear end” (nose-to-tail) crashes; in 2018 there were 1162 rear-end injury crashes. That’s over 10% of all injury crashes, so perhaps worth exploring. What could we do to reduce all these crashes? Maybe more skid-resistant road surfaces, or better visibility of things like traffic lights and hidden queues. Possibly encourage more take-up of cars with automatic brake assist, or even more education and enforcement of drivers around not following too closely.
All this effort might see a good reduction in those rear-end crashes, but let’s look at the casualties from those incidents. Most of them were minor (i.e. non-hospital) injuries; there were only 7 fatalities and 98 serious injuries. Is it worth focusing a lot of effort on this issue if we want to get our casualty statistics down?
Compare that with “head-on” collisions: in 2018 there were only 773 of those (less than 7% of all injury crashes). But those 773 crashes were responsible for 134 deaths (more than one third of the year’s total) and another 383 serious injuries.
What would help reduce the likelihood and severity of head-on crashes? Education and enforcement focus on driver fatigue and distraction might help, although it is hard to dramatically improve driver behaviour in these areas. An obvious one is more centreline median barriers, preventing encroaching into the oncoming traffic. Maybe improving the alignment, width and sightlines of some roads would also reduce the likelihood of crossing the centreline.
All those engineering solutions cost a lot of money though, so they won’t be cost-effective everywhere. That’s where lower speed limits also come into play; we have a lot of rural roads in particular where the standard 100 km/h limit is completely inappropriate for the road geometry. Slowing down traffic can greatly reduce the potential impact speed of two oncoming vehicles. Note, this is not the same as focusing on speed enforcement, often widely panned in NZ, it’s about reducing the expected travel speeds for various roads in the first place.
Let’s have another look at those median barriers. While they are likely to dramatically reduce the likelihood of head-on crashes on the other side of the road, you are equally likely to increase the number of crashes into those barriers (or even into other vehicles on the same side of the road as you). The difference however is that these types of crashes are much more forgiving than head-on ones – you are highly likely to still come out very much intact.
This focus on deaths and injuries rather than crashes also accepts the fact that we humans are fallible and make mistakes and poor decisions sometimes. Scandinavian and Australian research found that, even if road users followed all the road rules, fatalities would only fall by around 50% and injuries by 30%. So we need to come up with ways to prevent people dying as a result of a “simple error” by them or someone else.
Tackling road safety in New Zealand will require a multi-faceted approach; there is no one “silver bullet”. But it is important that we focus on the most appropriate treatments to reduce deaths and injuries, rather than simply what might reduce crashes.
Dr Koorey is a Principal with ViaStrada Ltd in Christchurch. He specialises in road safety and sustainable transport, with a particular focus on speed management.