Significance of Class Association of Shoe Prints

1. Significance of Class Association of Shoe Prints Sandy Parent Texas Department of Public Safety

2. What is the likelihood that two people would have a shoe similar in tread pattern, size and wear and wear the shoe to the same place on the same day?

3. Random Population • Various ages • Males and Females • Various professions • Various income levels • Various origins = Many different types of footwear

4. Texas Department of Public Safety Driver’s License Building Study 1: July 2004 (3 days) Austin Study 2: March 2005 (2 days) Austin Garland Houston Lubbock McAllen

5. ▲ Garland ▲ Lubbock Austin ▲ Houston Austin ▲ McAllen

6. Collection • Individuals were asked to participate in study • Right shoe sole • Documented information: • Manufacturer • Style (Dress, Casual, Athletic, Sandal, Boot) • Size • Male / Female • “Invisible Ink” Method – Armor Holdings

7. Invisible Ink Methodby Armor Holdings

8. Study 1 – July 2004 – 3 days Austin, TX 555 Shoe Prints Study 2 – March 2005 – 2 Days 236 Shoe Prints / Austin 205 Shoe Prints / Garland 236 Shoe Prints / Houston 181 Shoe Prints / Lubbock 194 Shoe Prints / McAllen Total – 1052 Shoe Prints 1607 Shoe Prints

9. Study 1 – 555 Shoe Prints • Athletic Shoes – 207 • Sandal – 204 • Casual – 84 • Boot – 32 • Dress – 27 • Unknown – 1

10. Study 2 – 1052 Shoe Prints • Athletic – 430 • Sandal – 129 • Casual – 261 • Boot – 133 • Dress – 99

11. Study Comparison Study1 Study 2

12. OVERALL – 1607 Shoe Prints • Athletic – 637 • Sandal – 333 • Casual – 345 • Boot – 165 • Dress – 126 • Unknown - 1

13. Market Analysis • Athletic • Nike 157 • New Balance 65 • Reebok 60 • Adidas 41 • K Swiss 26 • Skechers 32 • Casual • Skechers 18 • Polo 16 • Rockport 15 • Sandals • Reef 21 • Old Navy 18

14. Size 7 – 18 Size 7.5 – 23 Size 8 – 43 Size 8.5 – 59 Size 9 – 102 Size 9.5 – 80 Size 10 - 105 Size 10.5 – 95 Size 11 – 91 Size 11.5 – 32 Size 12 – 86 Size 12.5 – 3 Size 13 – 51 Size 14 - 13 Male Shoe Sizes * Based on information provided by participant

15. Size 5 – 19 Size 5.5 - 22 Size 6 – 46 Size 6.5 – 44 Size 7.0 - 114 Size 7.5 – 77 Size 8 – 107 Size 8.5 – 73 Size 9 – 81 Size 9.5 – 29 Size 10 - 39 Size 10.5 – 3 Size 11 – 13 Female Shoe Sizes * Based on information provided by participant

16. “Class Characteristic – An intentional or unavoidable characteristic that repeats during the manufacturing process and is shared by one or more shoes”- Bodziak, William Footwear Impression Evidence Detection, Recovery, and ExaminationTread Pattern, Size and Wear

17. Tread Pattern • Gross Design • Variation in the Manufacturing Process • Mold vs. Cut • Texture • Stippling • Chemical Acid Etching • Limitations • Featureless soles • Large amount of wear • Partial imprints

18. Elimination – Tread Pattern

19. Elimination – Tread Pattern

20. Elimination – Tread Pattern

21. Elimination – Tread Pattern

22. Elimination - Tread Pattern

23. Elimination – Tread Pattern

24. Elimination – Heel Tread

25. Elimination - Tread Pattern

26. Size / Dimensions • Physical Dimensions of the imprint • Not related to the manufacturer size • Superimpose imprints (Overlay Method) • Limitations – • Partial imprints • Heavily saturated imprints

27. Elimination – Size Reebok Size 2.5 M (Youth) Reebok Size 8 M

28. Wear • The effect of frictional or abrasive forces on the shoe sole • The removal of portions of the design • Noticeable differences in the worn versus unworn areas of the shoes • Position and degree of wear • Schallamach Pattern • Limitations: • Undefined or minimum amount of wear • Heavily saturated imprint

29. Schallamach Pattern

30. Elimination by Wear

31. Elimination - Wear

32. Elimination – Overall Size

33. Old Navy – Flip Flops 13 Shoes / 78 Possible Pairs Indistinguishable Pairs: Tread - 4 Size / Dimensions - 2 Wear - 0

34. Reebok 8 shoes Reebok 3 shoes

35. Manufacturer: Skecher Number Collected: 10 Possible Pairs: 45 Indistinguishable Pairs: Tread Pattern – 45 pairs Size – 1 pair Wear - 0

36. Manufacturer: New Balance Number Collected: 8 Possible Pairs: 28 Indistinguishable Pairs: Tread Pattern – 28 pairs Size - 0 Wear – Not Applicable

37. Manufacturer: New Balance Number Collected: 7 Possible Pairs: 21 Indistinguishable Pairs: Tread Pattern – 6 Size - 0 Wear – Not Applicable

38. Tread Pattern - Elimination

39. Comparison • Local Populations • Total Population Assess the Significance based on: • Toe Area • Tread design  Size/Dimensions  Wear • Toe + Heel Area • Tread design  Size/Dimensions  Wear

40. *( ) = Featureless soles

41. Indistinguishable Pairs Toe Toe and Heel # prints / possible pairs Tread Pattern Size Wear Tread Pattern Size Wear Austin 236 / 27730 30 0.11% 20  0.07%  9 0.03% 7 0.03%  0  N/A Garland 205 / 20910 36 0.17% 18 0.08% 6 0.03% 24 0.11% 3 0.01% 0 Houston 236 / 27730 44 0.16% 25 0.09% 5 0.02% 24 0.09% 1 0.0% 0 Lubbock 181 / 16290 29 0.18% 18 0.11% 2 0.01% 11 0.07% 0 N/A McAllen 194 / 18721 43 0.23% 35 0.19% 4 0.02% 16 0.09% 2 0.01% 0

42. *( ) = Featureless soles

43. Indistinguishable Pairs

44. What is the likelihood that two people would have a shoe similar in tread pattern, size and wear and wear the shoe to the same place on the same day?

45. State of Alaska Crime Lab-Lesley Hammer & Janeice Amick • Collected right shoe imprint from 353 individuals at the local DMV in 2006 • Majority appeared to be athletic footwear • Unable to infer age of person from shoe imprints • Similar design worn by 15 year old & 45 year old • Similar design and size worn by 44 yo & 77 yo • Results – 1 pair was determined to be indistinguishable based on design and size • Adidas – size 7.5 – 16 year olds • Appeared to have same stippling in a small area

46. Special Thanks To: • Allen Miller – Armor Forensics • Christi Wells & Greg Jellik • Micheal Villarreal, Jose Zuniga, Devin Crago and Lan Bundy • TX DPS Management • William Bodziak

47. Contact Information Sandy Parent P.O. Box 4143 MSC 0460 Austin, TX 78765-4143 (512) 424-2105 Sandy.Parent@txdps.state.tx.us