The presumptions that 0.10 percent BAC equals impairment and that the body eliminates alcohol at the rate of 0.015 percent BAC per hour are based on population averages. Conversion of the BrAC to BAC again depends on presumptions about human physiology and the validity of the conversion rate and should not be applied to all individuals. The use of presumptions which shift the burden of proof to the defendant is unconstitutional; constitutional protection has recently been extended to DUI (driving under the influence) offenses. Research shows that individual alcohol elimination rates vary from 0.006 percent to 0.04 percent BAC per hour. The presence of food in the stomach and body temperature, also erroneously presumed to be a constant, can affect both the absorption and elimination rates. DUI defendants are frequently convicted on the basis of the presumptions mentioned. The drinking and driving problem should be curtailed, but while the DUI statute system removes some alcohol-impaired drivers, it fails to remove those who are impaired by drugs or who are simply poor drivers, and sometimes leads to wrongful convictions of unimpaired drivers. A test using microcomputer technology should be developed whereby driving impairment due to alcohol can be measured and confirmed, and impairment due to medical problems can be aided and exonerated.