Citation

Martin TL, Wigmore JG, Woodall KL. J. Can. Soc. Forensic Sci. 2004; 37(4): 187-195.

Copyright

(Copyright © 2004, Canadian Society of Forensic Science, Publisher Informa - Taylor and Francis Group)

DOI

10.1080/00085030.2004.10757575

PMID

unavailable

Abstract

Two hundred and thirty self-reported drinking scenarios from drinking-drivers charged with an impaired driving offence were examined. Estimated blood alcohol concentrations (eBAC) from drinking scenarios were calculated using standard forensic calculations (i.e. Widmark Formula) and compared to the lowest or first Intoxilyzer® 5000C results. Using a rate of elimination of alcohol from the blood of 10 mg/100 mL/h, eBACs were more than 10 milligrams of alcohol in 100 millilitres of blood (mg/100 mL) lower than the Intoxilyzer® 5000C results in 194 scenarios (84%), within ±10 mg/100 mL of the Intoxilyzer® 5000C result in 32 (14%) drinking scenarios and more than 10 mg/100 mL higher than the Intoxilyzer® 5000C result in 4 (2%) drinking scenarios. The number of eBACs more than 10 mg/100mL lower than the Intoxilyzer 5000C increased to 221 (96%) when a rate of elimination of 20 mg/100mL/h was employed. The greatest discrepancy observed was a truncated Intoxilyzer® 5000C result of 300 mg/100 mL and a corresponding eBAC of less than 10 mg/100 mL. Test records for each Intoxilyzer® 5000C test were examined and all instruments were verified as calibrated and in proper working order at the time of testing. It is concluded that the vast majority of drinking scenarios provided by arrested drivers are unreliable when compared to the Intoxilyzer® 5000C.