IAI Footwear flashcards
IAI Footwear · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Class characteristics
- Features shared by a group of shoes or tires, such as tread pattern, size, and pitch, that narrow the candidate pool but cannot identify a single source.
- Individual characteristics
- Unique features such as cuts, wear patterns, embedded objects, and manufacturing defects that can link an impression to a specific shoe or tire.
- Pitch
- The center-to-center distance between repeating tread design elements; measure over several repeats and average to reduce error.
- Sipe
- A thin slit molded into a tread lug or rib that improves traction and leaves fine lines in an impression; usually a class characteristic.
- DOT date code
- The final four digits of a tire's DOT serial, where the first two digits give the week and the last two the year of manufacture.
- Tire size P225/60R16
- P means passenger, 225 is section width in mm, 60 is aspect ratio, R is radial, and 16 is rim diameter in inches.
- Track width
- The distance between the centers of the left and right tire tracks on the same axle; used to narrow vehicle class.
- Wheelbase
- The distance between the front and rear axle centers of a vehicle; measured from tracks to support vehicle class comparison.
- Dental stone casting
- A method for recovering three-dimensional impressions in soil or snow; mix per instructions, pour from one edge, and allow full set before lifting.
- Electrostatic dust print lifter
- A device that lifts dry, dusty impressions from hard surfaces onto a film; ineffective on wet or greasy residues.
- Gelatin lifter
- An adhesive gel sheet used to recover impressions in blood or wet residue from surfaces and fabrics.
- Amido black
- A protein stain used to enhance bloody footwear impressions; DNA should be swabbed before application because the stain can affect later analysis.
- Leucocrystal violet
- A reagent that enhances blood impressions by producing a colored reaction; document and swab for DNA before use.
- Ninhydrin
- A reagent that reacts with amino acids to develop latent impressions on porous surfaces such as paper; applied after physical developer in some sequences.
- Physical developer
- A silver-based reagent for latent impressions on porous surfaces, especially paper that may have been wet; order of use matters.
- Oblique lighting
- Lighting directed at a low angle across an impression to reveal tread detail and contrast; used in photography of both footwear and tire evidence.
- Test impression
- An impression made with the actual shoe or tire in a medium matching the questioned impression, used for comparison.
- ACE-V
- Analysis, Comparison, Evaluation, and Verification; a framework for impression examination with documented stages and second-examiner verification.
- Stride length
- The heel-to-heel distance between successive impressions of the same foot; in normal gait roughly twice the step length.
- Step length
- The heel-to-heel distance between successive impressions of alternating feet; used with stride length to reconstruct gait.
- Walking base
- The midline-to-midline distance between the left and right footprints; a gait measurement recorded in centimeters.
- Skid mark
- A tire mark left during braking; length and curvature are measured to estimate speed using drag factor and braking distance.
- ABS dash marks
- Intermittent tire marks left by anti-lock braking; their spacing reflects the ABS cycling and should not be mistaken for tread pitch.
- Direction of travel
- Inferred from deeper soil throw at the toe, a cleaner heel edge, or a compression wave ahead of a tire and ejection behind it.
- Inconclusive conclusion
- A reported result when the evidence lacks sufficient class or individual detail, or is too distorted, to support identification or exclusion.
- Exclusion
- A conclusion that a shoe or tire did not make an impression, based on a demonstrated disagreement in class or individual characteristics.
- Chain of custody
- The documented record of evidence transfer, storage, and handling that supports admissibility and prevents tampering claims.
- Shoe size systems
- US, UK, and EU sizing are not interchangeable; EU size approximates last length in cm times 1.5, so report the system used.
- Siping density
- The number and spacing of sipes per lug or rib; a class characteristic used to distinguish tire models and types.
- Tread depth gauge
- A tool that measures tread depth in millimeters or 32nds of an inch; record the unit and convert consistently when comparing.
- Photogrammetry
- A method that produces measurable three-dimensional models from photographs; used to document impressions with stated measurement uncertainty.
- Mold-flow line
- A manufacturing artifact on an outsole from the mold; a sub-class characteristic rather than an individual feature.