Revise certain provisions related to operating a vehicle, boat, or aircraft while under the influence.
HB1120 revises South Dakota’s impaired-operation laws for vehicles, boats, and aircraft. The bill updates the statutory language governing when a person is considered under the influence, including alcohol concentration thresholds, drug and marijuana impairment standards, and the use of chemical test results from breath, blood, or other bodily substances. It applies to commercial motor vehicles, ordinary vehicles, boats on public waters, and aircraft, and it also modernizes phrasing around presumptions used in criminal prosecutions.
For motor vehicles, the bill keeps the 0.08 percent alcohol limit for general DUI offenses and the 0.04 to 0.08 percent range for commercial motor vehicles, while clarifying that impairment may also be based on marijuana, controlled substances, prescription drugs, or other substances that make a person incapable of safe driving. It also revises the presumptions tied to blood alcohol levels in DUI cases and under-21 driving offenses, and it maintains the separate under-21 offense with a 0.02 percent threshold and drug-related restrictions. For boats and aircraft, the bill similarly updates the intoxication standards and preserves the existing misdemeanor penalties for operating while impaired.
HB1120 would amend several chapters of South Dakota law, including the motor vehicle DUI statutes, the under-21 alcohol/drug driving law, the boating under the influence law, and the aircraft operation under the influence law. The bill does not appear to create a new offense category so much as revise and harmonize existing standards, evidentiary presumptions, and wording across transportation modes. It would continue to authorize criminal penalties, including Class 1 and Class 2 misdemeanors, and would preserve license suspension consequences for under-21 violations.
The available vote history suggests the bill had mixed support but enough backing to advance at least temporarily, with an 8-4 vote to defer it to the 41st legislative day. No committee transcript is available, so there is no recorded debate to show detailed arguments for or against the measure. Based on the bill text, the overall policy direction appears to be a technical and substantive tightening/clarification of impaired-operation laws rather than a major new regulatory scheme.
The likely points of contention are the bill’s treatment of marijuana and other controlled substances, the continued use of blood alcohol presumptions, and the scope of impairment standards across vehicles, boats, and aircraft. Supporters may view the bill as a needed update to align statutes and improve enforcement clarity, while opponents may object to how broadly impairment is defined or to the criminal penalties and license consequences that follow. The deferment vote indicates at least some legislative hesitation, but the record provided does not identify specific members or arguments.