Field sobriety test

Answer to Case A Bloodshot eyes and poor coordination are hallmark signs of marijuana intoxication. The driver may have finished smoking marijuana before getting into the car, explaining the absence of odor, or may have ingested the marijuana. The level of alcohol is too low to account for poor coordination and the failing of the field sobriety tests. A urine sample should be collected and tested by EMIT and, if positive for cannabinoids, confirmed by GC/MS. 

Answer to Case C Two types of analysis would have been helpful. An analysis of blood would have been a better indicator of causality than a urine sample. If benzodiazepines were found in the blood, the type of benzodiazepine and its concentration would have helped establish whether or not the driver was impaired. An examination by a DRE might have revealed any drug-related physiological effects, and performance of field sobriety tests might have indicated impairment. 

Kennedy, R.S. et al., Indexing cognidve tests to alcohol dosage and comparison to standardized field sobriety tests, J. Stud. Alcohol, 55, 615, 1994. 

DWI Cues and the Standardized Field Sobriety Test (SFST). Given the wide array of psychomotor and cognitive fiinctions affected by alcohol it was only natural that attempts would be made to provide police officers with a useful behavioral field tool to assess alcohol impairment. Two such tools have been developed the DWI Cues guidelines and the Standardized Field Sobriety Test (SFST). 

Stuster, J. (2006). Validation of the Standardized Field Sobriety Test Battery at 0.08% Blood Alcohol Concentration. Hum. Fact, 48(3), 608-614. 

Stuster, J. and M. Bums (1998). Validation of the standardized field sobriety test battery at BACs below 0.10 percent. NHTSA Report DOT HS 808 839. U.S. Department of Transportation, Washington, DC. 

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