NCJ Number
220413
Journal
Journal of Forensic Sciences Volume: 52 Issue: 5 Dated: September 2007 Pages: 1050-1056
Date Published
September 2007
Length
7 pages
Annotation
This study used pyrolysis gas chromatography/mass spectrometry (GC/MS) to analyze traces of tire material left after braking, in order to determine whether the analysis could distinguish tires by their manufacturer.
Abstract
All 12 of the tires could be distinguished by using linear discriminant analysis (LDA), and 10 of the 12 tires could be differentiated by using target compound identification (TCI). The analysis determined that the tires were not homogenous and that differences could be observed in the repeat analysis of a sample. Physical changes were also observed between the tire sample and the skid-mark sample. Because of the changes that occur in tire material in the course of the skid, skid-mark samples are more likely to be identified correctly when compared with other skid-mark samples rather than the tires. Such an analysis is useful in identifying the tires of a vehicle involved in a hit-and-run accident when skid-marks are involved. Twelve tires from different manufacturers were used to create the braking marks. Braking marks were produced under controlled conditions, i.e., with a vehicle traveling at 60 km/h on a concrete road that contained gravel aggregate. The section of road used for each braking incident was clear of any visible tire marks. The tire rubber from the skid marks was collected directly off the road surface with tweezers. Each of the 12 samples was examined for both consistencies and inconsistencies over the duration of the chromatogram and through 6 repeat analyses. Pyrolysis was performed using a Shimadzu Furnace Pyrolyser-4a Ver.2 set at 450 degrees centigrade, mounted on the split injector of the GC/MS. The analysis was performed using a Shimadzu GC-17A gas chromatograph coupled to a Shimadzu GCMS-QP5050A mass spectrometer. 4 tables, 5 figures, and 6 references