NCJ Number
116911
Journal
Criminal Justice Volume: 4 Issue: 1 Dated: (Spring 1989) Pages: 4-7,37-39
Date Published
1989
Length
7 pages
Annotation
Drunk-driving (DWI) statutes and their related jury instructions must be revised to comply with both scientific truth and constitutional law.
Abstract
State per se DWI laws presume mandatory guilt based on a measurement of blood alcohol content (BAC), often with permission to infer BAC from a breathalyzer measurement. There are several problems with jury instructions under such laws. To be constitutional, the jury instructions must make clear that the prosecution has the burden of proving all preliminary factual presumptions underlying the ultimate fact, i.e., that the BAC was precise and valid at the time of the offense, beyond a reasonable doubt. The prosecution's burden of proof should include the precision and validity of the breath tests administered to the defendant, their precision and validity as indicators of blood alcohol content, and the prediction of BAC at the time of the traffic incident from that presumed from the test. Many statutes have unconstitutionally converted these assumptions to presumptions, thus precluding the necessity of the prosecution's proving the existence of facts crucial to a determination of guilt. An improved approach to reducing impaired driving for whatever reason would be to develop a driving simulator for use by law enforcement to provide a direct determination of impaired driving. Only after evidence of impaired driving is shown should the cause and culpability of such impairment be explored.