There are a lot of factors that play into a BAC measurement. For starters the liver metabolizes alcohol at the rate of .015 of blood alcohol concentration (BAC) per hour however that is dependant on when you stopped drinking and whether or not you ate before hand. Eating before hand can decrease the amount of alcohol metabolized.JSThane wrote:I thought that was already the case in multiple jurisdictions.baldeagle wrote: If we know that BAC changes at the rate of 2% per hour and it takes four hours to get the warrant and take the sample, can't the DA argue in court that the true BAC is 8% higher than the measured BAC? After all, it's scientifically valid.
If I stop you 1 hour after drinking your BrAC/BAC could very well still be on the rise so an argument could be made that at the time of arrest BAC was lower/higher but you would have to know the exact circumstances and that is impossible. Your BAC might not stop rising for a few hours after you had your last drink, again depending on when you ate, etc. Also, livers exposed to heavy drinking mtabolize at a slower rate.
I think the idea of obtaining a warrant is a good protection of the 4th Amendment in so that typically if someone is driving drunk and their ability is noticably affected (i.e. I can run the standardized field sobriety tests on someone and given their performance I can give you an estimate that consistently will be within 0.02 of their measured BAC (either blood/breath).
Furthermore, 0.08 is a presumptive level of intoxication. If their behavoir and abilties are noticeably diminished, as a result of drugs, alcohol or other substance, they are just as guilty of DWI.
ETA: I have DWI convictions with no BrAC/BAC as well as one as low as 0.039. It is rememberable because she was speeding, hopped a curb and parked ontop of a pile of asphault for a construction project on Lackland AFB. I am talking, the car was tetering on the top of that triagle cone. She was 100 lbs soaking wet and our IG Inspection was going on at the time (my flight got recognized for our performance and professionalism)