House approves lowering legal BAC to 0.05 after extended floor debate

The Utah House on Monday approved first substitute House Bill 155, a proposal to lower the legal blood‑alcohol concentration (BAC) threshold for impaired driving from 0.08 to 0.05.

Representative Thurston, the bill sponsor, told colleagues the measure aligns Utah with international practice and cited studies estimating roughly an 11 percent reduction in alcohol‑related traffic fatalities if the change were broadly adopted. Thurston described the change as a public‑behavior policy that reduces the social tolerance for driving after drinking rather than a major enlargement of law‑enforcement powers.

Opponents and questioners raised concerns about enforcement and whether law‑enforcement tools would need to change. Thurston and other backers said current procedures — stopping for probable cause, field‑sobriety testing and post‑arrest testing — remain in place and would work under 0.05 without additional troopers. Representative Wheatley and others pressed Thurston on the practical impacts, and Thurston answered with examples about servings of alcohol (he estimated 2/3 of a bottle of wine or three standard shots could put an average 160‑pound person at 0.05).

Supporters argued the law would change social behavior and reduce impaired drivers on the road. Representative Hutchings said the measure is a step toward improved safety, while Representative Chavez Houck urged the body to consider distracted driving and other competing public‑safety issues.

After extended debate and a motion to end debate, the House voted to pass the first substitute HB 155 by a roll call of 48 yes and 26 no. The bill will be referred to the Senate for further consideration.