Who doesn’t like cheese? Whether the milk product comes from cows, sheep, goats or camels, people the world over treasure thousands of mouth-watering varieties. Heck, even non-dairy vegetableists happily consume products labeled as cheese.
For the sake of this discussion, we’ll zero in on Swiss cheese. What? What does Swiss cheese have to do with motorcycle safety? Almost nothing actually; it’s the holes we should be worried about.
But first, let’s look at an actual on-road motorcycle incident which occurred in September 2019. It happened on a sunny day at a minor junction on a straight stretch of clean, dry road. Beyond the riders involved - a tour group - there was no other traffic on the scene at the time. Interestingly, every one of the people involved were competent high-mileage riders who had benefitted from on-road advanced rider training. Thankfully, although one motorbike was too damaged to continue, no one was seriously injured.
No. 1 was the group leader. Before turning right into the sideroad and parking area he did not signal to the rider immediately behind to mark the junction. He assumed that those who were following saw him exiting the main road and would simply follow. The error? The leader did not properly assign the task, and a specific spot, for marking the turn-off.
The rider of bike no. 2, aware that some remaining riders were well back, stopped in this location to mark the junction. The error? This person was partially out of the sight of following riders.
Rider no. 3, upon catching up with the first few riders, did not immediately see #2 marking the junction, nor other riders already stopped in the parking area. A split second later #3 did see either the junction marker, or the riders in the parking lot, commenced very hard braking and came to a complete stop in their lane. The error? Not first taking rear observation, such as a mirror check, before (hard) braking.
No. 4, whose focus was on #3, was able to react and brake in time to avoid colliding with #3. Rider 4’s error? None, although rather unfortunately this rider received the biggest battering.
Rider no. 5, whose initial focus was on riders #3 and #4 ahead, became momentarily distracted by the riders in the parking area, at exactly the same moment as #3 began braking very hard. As a result, #5 was not left with sufficient time to change direction, reduce speed, and avoid careening into #4 and #3. No. 5’s error? Removing their focus on the most immediate hazards; the riders ahead.
So, what do holes in cheese have to do with this accident? It illustrates the Swiss cheese model of accident causation, originally formally advanced by Dante Orlandella and James T. Reason of the University of Manchester. The model is used in risk analysis and risk management, including aviation safety, engineering, healthcare, and as the principle behind
layered security.
In the Swiss Cheese model, defenses against failure are modeled as a series of barriers, represented as slices of cheese. The holes in the slices represent weaknesses in individual parts of the system and are continually varying in size and position across the slices. The system produces failures when a hole in each slice momentarily aligns, permitting (in Reason's words) "a trajectory of accident opportunity", so that a hazard passes through holes in all the slices, leading to a failure. (source: Wikipedia)
In the accident scenario illustrated above, none of the small errors, on their own, were enough to cause the accident. It was only because they all lined up at the same time, that the mishap occurred. There was a very linear “trajectory of accident opportunity". Remove any of the seemingly small errors and this incident would never have happened.
What can we learn from this? That very small changes at initial stages can create significantly different outcomes further along. A misjudged lane position, inappropriate speed for road and traffic conditions, a missing observation, a momentary lapse of attention or a distraction may or may not make much difference on its own. However, depending on timing, and the opportunity holes lining up, we can all too easily find ourselves at the point of failure - an accident.
So, whether you’re planning to visit England’s Cheddar Gorge, Roquefort in France, or Gouda in the Netherlands, be alert to Swiss cheese holes. Although not shown on any Michelin roadmap, they’re everywhere.
Michael Moloney ©2019
peakrideradventure.com
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