I've got a stop for expired registration. Officer pulls over Defendant. Officer smells alcohol. Officer gives SFSTs. Defendant is arrested for DWI and acknowledges drinking one rum and coke 5 hours earlier.

Search warrant results in blood sample. Blood test results are 0.00 for alcohol and .29 milligrams per liter for methamphetamine.

What I need now is (1) Does anyone know of an expert witness on the issue of impairment of mental / physical faculties by the introduction of methamphetamine into the system; and (2) are they able to quantify at what level impairment would begin / be evident?

I had a case in 2003 -- Patrick Sean McKenzie, 11-03-00413, 2005 Tex App LEXIS 877, 2/3/2005 where the chemist testified regarding meth. intoxication. She was from DPS -- Kathy Erwin. The issue on appeal was the insufficient evidence of intoxication by meth. It might be a place to start.

Robert,
check your email....

Kathy is still with DPS. She's at the Austin lab. Very knowledgeable lady who can probably help. Another resource is Sarah Kerrigan who spoke at last year's Intox Manslaughter seminar. She is the director of the Forensic Science Program at Sam Houston State in Huntsville.