Crash test dummies are built from a combination of steel, aluminum, rubber, and various polymers, all layered together to mimic how a human body moves and absorbs force in a collision. A single fully instrumented dummy costs about $1 million, and that price reflects the precision engineering packed into every joint, rib, and sensor. Far from being simple mannequins, these devices (officially called anthropomorphic test devices, or ATDs) are some of the most carefully specified human stand-ins ever manufactured.
The Steel and Aluminum Skeleton
At the core of every crash test dummy is a rigid metallic frame that serves the same purpose as a human skeleton. The spine is typically a solid metal column, and the pelvis is a machined aluminum or steel assembly with detachable components on each side. This internal structure gives the dummy its overall shape and provides mounting points for the ribs, limbs, and sensors that measure what happens during a crash.
The materials need to be strong enough to survive repeated high-speed impacts without permanently deforming, yet shaped and weighted to respond the way real bone would. Aluminum is used where lighter weight matters, while steel handles the areas that need maximum strength and stiffness.
Ribs Made From Spring Steel
The rib cage is one of the most carefully engineered parts of any crash test dummy. In the widely used Hybrid III dummy, six high-strength steel ribs curve around the chest area, each one lined with a polymer-based damping material. This combination is designed to compress under impact the same way a human chest does, then spring back to its original shape for the next test.
The damping layer is critical. Without it, the steel ribs would bounce back too fast and too hard, nothing like the way human tissue absorbs energy. The polymer slows the rebound and softens the force curve, giving engineers realistic data about how much chest compression a real person would experience. In side-impact dummies, the abdomen gets a similar treatment with additional flexible ribs that extend lower on the torso.
Rubber and Aluminum in the Neck
The neck is where crash test dummies face one of their toughest engineering challenges: replicating the complex motion of the human cervical spine. The Hybrid III neck solves this with alternating discs of rubber and aluminum, stacked like a column with a steel cable running through the center to hold them together.
The rubber segments flex and compress to simulate the bending and rotation of a real neck, while the aluminum discs provide structure and limit how far each segment can move. A newer articulated neck design adds spring-loaded “muscles” made from metal springs housed in 3D-printed plastic mounts, which pull the head back toward a neutral position after impact, much like the muscles in your neck would.
Vinyl Skin and Urethane Flesh
The outer layers of a crash test dummy simulate human soft tissue using several types of polymer. Vinyl is the most common skin material, molded to the shape of the body and thick enough to provide a realistic surface for seatbelts and airbags to interact with. Underneath the vinyl, urethane foam or cast urethane fills out the body contours to approximate the density and give of human muscle and fat.
The pelvis, for example, uses hard urethane “wings” to replicate the shape of the hip bones, covered by a layer of vinyl flesh. The chest is wrapped in a molded jacket that simulates the torso’s overall shape, including breast contours on female dummies. Getting this jacket right has been a decades-long process. Federal records show that after the 5th percentile female dummy was introduced in 2000, none of the chest jackets manufactured actually met the original government specifications. It took years of work between manufacturers and the National Highway Traffic Safety Administration to harmonize the design.
Even the formulation of the urethane changes over time. The raw material used for the pelvis wings was reformulated in 2004 after the original chemical was pulled from the market due to toxicity concerns. These material swaps require extensive retesting to make sure the dummy still responds like a human body.
Over 150 Sensors Inside
What makes a modern crash test dummy far more than a shaped collection of metals and plastics is the dense network of sensors woven throughout its body. The newest dummies contain more than 150 sensors, primarily small accelerometers that measure how fast different body parts speed up or slow down during impact, along with force transducers that record loads on specific bones and joints.
The head contains accelerometers that measure rotational and linear forces, calibrated by dropping the head from a set height and comparing its response to real concussion data. The neck uses a multi-axis force transducer to capture the whiplash forces that cause the most common crash injury. The chest measures how far the ribs compress inward. The femurs, tibias, and feet all have their own load cells to detect fracture-level forces in the legs. Pressure sensors in the abdomen detect internal organ-level impacts.
Every one of these sensors adds wiring, mounting hardware, and calibration requirements, which is a big part of why a single dummy carries a million-dollar price tag.
How Newer Dummies Improve on Older Designs
The Hybrid III has been the standard frontal-crash dummy since the 1980s, but a newer design called THOR represents a significant leap in how closely the materials and mechanics match a real human. THOR provides more realistic responses in the chest, shoulder, spine, knee, hip, lower leg, and abdomen compared to the Hybrid III. Its joints allow more natural motion, and its torso compresses in ways that better reflect how a real ribcage deforms.
The newest addition to the lineup is a 5th percentile female THOR dummy, built to better represent the anatomy of smaller women. It includes improved measurements for face loads, collarbone forces, abdominal pressure, and ankle movement. These are injury patterns that older dummies simply couldn’t detect, which meant cars were being optimized for impacts on a mid-size male body without capturing how crashes affect smaller occupants differently.
Why the Materials Matter So Much
Every material choice in a crash test dummy comes down to one concept called biofidelity: how closely the dummy mimics the way a real human body behaves during a crash. If the rubber in the neck is too stiff, the head won’t whip forward realistically and the sensor data will underestimate whiplash risk. If the chest ribs spring back too quickly, the dummy will underreport the kind of crushing forces that break sternums and damage hearts.
This is why the materials are specified down to fractions of an inch. Federal regulations for one side-impact dummy dictate that the neoprene padding must be exactly one-quarter inch thick (with a tolerance of just three sixty-fourths of an inch), laminated on both sides with a lightweight nylon mesh fabric no thicker than twenty thousandths of an inch. That level of precision ensures that every dummy built by every manufacturer responds identically, so a crash test run in Detroit produces the same data as one run in Tokyo.
The result is a device that looks like a simple foam-and-metal figure but is actually one of the most tightly controlled measurement instruments in engineering, with every layer of steel, rubber, vinyl, and urethane calibrated to tell engineers exactly what would happen to you.