When Numbers Start Making Decisions · Season Three, “The People the Average Does Not See” · Article 6
1. A standard occupant makes a reproducible crash possible
Vehicle safety regulation needs repeatable evidence. Cars cannot be compared if every crash uses a different occupant, seating position, speed and barrier. A standard dummy makes forces and injuries measurable under controlled conditions.
Australia’s side-impact design rule illustrates this logic. Australian Design Rule 72/01 specifies a dynamic side-impact test and uses a 50th-percentile adult male dummy in the prescribed procedure. Vehicle Standard (Australian Design Rule 72/01—Dynamic Side Impact Occupant Protection) 2023
“50th percentile” sounds like an average human. It is not. It refers to selected male body dimensions used to construct a standard surrogate. Women, smaller and larger adults, older bodies, pregnant occupants, children and people with disability are not scaled copies of that surrogate. Injury risk depends on anatomy, bone strength, seating position and interaction with restraints.
The dummy is indispensable as a measuring instrument. The question is how far passing a test with one standard body can justify a claim of safety for everyone inside the vehicle.
2. Standardisation and representativeness solve different problems
Standardisation asks whether the test can be repeated and vehicles compared. Representativeness asks whether the test population covers the people whose safety matters. A 50th-percentile male can be excellent for the first and incomplete for the second.
Regulatory tests define controlled crashes because real-world collisions vary endlessly. They encourage manufacturers to build structures, airbags and restraints that manage known loads. Common protocols also prevent firms from selecting favourable conditions for each vehicle.
But a design optimised around one dummy and position can perform differently for another body. Seat belts cross smaller torsos differently. Airbag timing, distance to the steering wheel and pelvis geometry matter. Older occupants can be more vulnerable at the same force. A short driver may sit closer to the wheel; a pregnant occupant has needs the standard body cannot reproduce.
The lesson is not that the standard dummy represents nobody. It represents one deliberately stable point in a diverse distribution. Its regulatory value is high, but its representational coverage is bounded.
3. A pass is a minimum result in a specified scenario
Australian Design Rules are national standards for vehicle safety, anti-theft and emissions. They prescribe technical requirements vehicles must meet before supply. Department of Infrastructure: Australian Design Rules
Compliance means a vehicle satisfied the defined test. It does not mean that every possible occupant will avoid injury in every crash. Speed, impact angle, compatibility with another vehicle, rollover, secondary impacts and emergency response all affect outcomes.
This distinction often disappears in public language. “Meets the safety standard” can be heard as “safe”, even though the standard is a floor under specified conditions. A test result should therefore be communicated with its scenario: which body, seat, impact and injury criteria were tested.
Standards can expand over time. New dummies, sensors and simulations permit evaluation of more occupants and crash modes. The difficulty is to improve representation without destroying comparability or making compliance technically unworkable. Layering tests is usually more productive than searching for one universal dummy.
4. The average can make systematic risk invisible
If safety performance is measured mainly around a standard male body, harms experienced more often by other occupants can look like individual exceptions. Yet repeated exceptions are distributional evidence. Real-world crash data can show whether women, older people or occupants at size extremes experience different injuries after accounting for crash conditions.
Such evidence tests whether the laboratory’s standard scenario predicts the outcomes that matter. When a vehicle performs well in the prescribed test but a group experiences worse outcomes, the answer should not be that those bodies deviated from the norm. The testing system’s coverage is the object requiring examination.
Australia’s transport department has itself discussed the historical relationship between women, vehicle design and crash injury. Women behind the wheel: young drivers The existence of a standard occupant reflects technical history and available tools, not a philosophical decision that one body deserves protection more than another.
Distributional safety reporting should examine injury types, seating positions, age, sex and body size where data allow. Aggregate fatalities or one dummy score cannot show who received the benefit.
5. Consumer testing can broaden the regulatory floor
Independent rating programs often test beyond minimum regulation. ANCAP’s 2026 protocols introduced new tools and scenarios, including a small adult female dummy in the front passenger seat in frontal testing and updated adult male technology. ANCAP: 2026–2028 test and rating criteria
This does not instantly solve representation. A small female dummy is still a standardised surrogate, not every woman or smaller person. But adding it changes design incentives. Manufacturers must consider restraint performance across more than one body, and the rating communicates a broader conception of occupant protection.
Regulation and consumer testing can play complementary roles. The legal standard supplies a stable minimum. Ratings create pressure for improvement and faster adoption of new methods. Real-world surveillance then checks whether both predict actual harm.
Versioning matters. A five-star vehicle assessed under one year’s protocol may not have passed the later protocol. Clear test years preserve comparability without pretending that safety knowledge has stopped.
6. Simulation adds coverage but needs validation
Computer human-body models can vary anatomy, posture and crash conditions more cheaply than physical dummies. They offer a way to explore pregnant occupants, older bodies and size ranges that would be impractical to represent with a separate physical instrument for every case.
Models, however, inherit assumptions from the data used to build them. A large simulation matrix can create an appearance of inclusion while producing uncertain predictions for poorly validated groups. Physical tests, cadaver research, clinical injury data and real-world crashes remain necessary to validate model behaviour.
The right structure is a portfolio of evidence: repeatable physical standards, multiple occupant surrogates, validated simulation and post-market crash outcomes. Each sees a different part of reality, and inconsistencies between them should drive revision.
7. A practical framework for standard bodies
When a standard person is used to certify a product, ask:
- Which dimensions and population does the surrogate represent?
- Which bodies, postures and vulnerabilities are absent?
- Is the test a minimum legal standard or a broader performance rating?
- What crashes and seating positions are outside the scenario?
- Do restraint and structure results change with occupant size?
- What does real-world injury data show across groups?
- Can additional dummies and validated simulation broaden coverage?
- Is the test version clear when results are communicated?
The aim is not a test without abstraction. No test can reproduce every road event. The aim is an abstraction whose omissions are visible and progressively reduced.
Conclusion: a standard occupant should be a reference point, not the human default
The 50th-percentile male dummy helped make vehicle safety measurable and enforceable. Its stability allows engineers and regulators to compare designs and improve protection. Removing standardisation would not make testing more humane; it would make evidence less reliable.
My judgement is that the standard dummy is legitimate only as one reference within an expanding system. Legal compliance should remain tied to its stated scenario, consumer testing should broaden bodies and crashes, and real-world outcomes should be able to disprove laboratory confidence.
The person closest to the statistical centre is not the person from whom everyone else is a deviation. Safety begins when the standard is recognised as a tool, not a definition of the public.
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