Week 10: Communicating risk to visitors and new drivers

Why a dense, legalistic warning fails the exact reader who needs it most — and what a plain-English brief has to do instead.

26 April 2027

Open the slides

A warning that technically states every risk and a warning that actually gets read, understood, and acted on are not the same document. This lecture is about the gap between them, using a deliberately bad example to see exactly where a warning fails, and what replaces each failure.

A note on who this is about. This unit’s synthetic dataset isn’t built to test who is more likely to hit a kangaroo in the real world, and this lecture won’t claim international visitors or newly licensed drivers are less careful — that would be an empirical claim with no source behind it here. What can be said without that claim: a driver with no local reference points needs a different brief than one who already has one, regardless of who happens to be holding the wheel.

A fictional example of a warning that fails

The following notice is invented for this lecture — it is not a real rental company’s text, and no real company is being described.

IMPORTANT NOTICE TO ALL HIRERS: Please be advised that wildlife hazards including but not limited to macropodidae may be encountered at any time throughout the geographic operating region during the currency of this rental agreement, and that the Hirer assumes full responsibility for any collision, damage, or injury arising therefrom irrespective of time of day, and that failure to exercise due care as determined solely by the Company may result in forfeiture of the security deposit in its entirety; refer to clause 14(b) for further particulars, and contact the Company’s after-hours assistance line, details of which are provided in Section 9 of the accompanying documentation pack, in the event of an incident.

Read it once, at speed, the way someone actually would at a rental counter. Notice what it fails to do: it names a risk category without saying when or where it matters most (dawn, dusk, and night on rural roads — buried behind “at any time”); its only clear instruction is a threat about the deposit, not an action to take; and the one genuinely useful piece of information — where to find the after-hours number — is hidden two documents deep.

Wrote it, read it, understood it, acted on it

A warning can satisfy all four of these and still fail at the third or fourth: wrote it (the company produced the text), read it (a person’s eyes passed over it), understood it (they could restate what it means), acted on it (their behaviour actually changed because of it). The notice above almost certainly clears “wrote it” and “read it” and fails hard at “understood it” — which makes “acted on it” impossible regardless of how accurate the underlying legal content is.

A road engineer’s view, from Dr Fenn. A standard diamond-shaped warning sign has exactly the same problem at a different stage: it clears “wrote it” easily (it’s installed, it’s visible), and usually clears “read it” for anyone paying attention — but it says nothing about when the risk is highest or what to do if an animal appears, so it can’t clear “understood it” for someone without prior local calibration either. The communication problem in this lecture isn’t unique to paperwork; a road sign and a rental notice fail the same way for the same underlying reason.

What a visitor doesn’t already know

A local driver has, usually without noticing, absorbed which roads run through likely habitat, what time of day matters most, what to actually do if an animal is on the road (this unit covered that in Week 9), and who to call if something happens. None of that is obvious to someone without it, and none of it is conveyed by a hazard category alone.

A plain-English information hierarchy

One sentence stating the risk in concrete terms, three specific actions, and a pointer to more detail for anyone who wants it — in that order, with nothing more load-bearing placed after the pointer:

Kangaroos and wallabies cross rural roads, especially at dawn, dusk and night. Slow down on rural roads during those hours. If you see one, brake steadily — don’t swerve. If you hit one, pull over safely and call [the after-hours number] — it’s on your key tag.

Rules for expressing the risk honestly

Before driving and while driving are different documents

What a driver needs before setting off (when the risk is highest, why this differs from wherever they’re used to driving) is different from what they need while driving (brake steadily, don’t swerve, what to do immediately after — Week 9’s material). Combining both into one dense paragraph is part of why the fictional notice above fails; splitting them lets each be short enough to actually read.

Does testing comprehension prove anything about outcomes?

Bagagiolo, G., Vigoroso, L., Caffaro, F., Micheletti Cremasco, M., & Cavallo, E. (2019), published in the International Journal of Environmental Research and Public Health, tested how well safety pictorials on agricultural machinery were understood by migrant farmworkers in Italy — not road signs, and not Australian tourists, but a structurally similar problem: an unfamiliar audience reading safety information designed by someone else. Comprehension varied sharply by group (68.8% for one nationality, 35.4% and 32.4% for two others), and no pictorial tested reached the 85% comprehension threshold used in ISO/ANSI pictorial standards. The authors themselves flag a small, non-random sample and confounded education and length-of-stay variables as limitations. Treat this study exactly as what it is: evidence that unfamiliar-audience communication needs to be tested, not assumed — not evidence about kangaroo signage specifically, and not proof that any particular fix here would work without its own testing.

Where this goes next

Testing whether a brief is understood is not the same as testing whether it reduces collisions — the same caution this week applies to comprehension testing, Week 11 applies to importing an entire intervention’s evidence from overseas. Understanding a warning and it changing an outcome are two different claims, and conflating them is the same mistake in a different costume.

Reading

Bagagiolo, G., Vigoroso, L., Caffaro, F., Micheletti Cremasco, M., & Cavallo, E. (2019). “Conveying safety messages on agricultural machinery: The comprehension of safety pictorials in a group of migrant farmworkers in Italy”, International Journal of Environmental Research and Public Health, 16(21), 4180. Read for the comprehension-testing method, not for any claim about road signage — it tests neither roads nor Australia.

Teaching team