A recent study done by a researcher at Colorado State University is making the case for Colorado lawmakers to change the state’s legal blood alcohol concentration (BAC) limit for DUI to be lowered from 0.08% to 0.05%, following Utah’s lead. A recent CBS Colorado story highlighted the new research. It suggests that a lower BAC limit could reduce fatal crashes. For Colorado drivers, however, the issue is more complicated than it first appears.
How would this be different from Colorado’s current DUI laws?
Unlike many states, there are already two primary levels of impaired-driving offenses in the Colorado DUI laws. A driver with a BAC of 0.08% or higher would be charged with Driving Under the Influence (DUI). A driver with a BAC between 0.05% and 0.08% may be charged with Driving While Ability Impaired (DWAI) if prosecutors can prove the person’s ability to drive was impaired to even the slightest degree. Both of these charges are serious, and they have almost the same legal consequences. So, if the Colorado legislature chose to lower the per se DUI limit to 0.05% as Utah did, it would not really create a brand-new category of offense. It would just make it easier for prosecutors to obtain full DUI convictions based solely on the chemical test result.
Research to support lowering the BAC cutoff for DUIs
The new research in support of lowering the BAC limit comes from Colorado State University researcher Kaigang Li, whose 2026 study (Li et al., 2026; also see Thomas et al., 2022) compared Utah with neighboring states, including Colorado, after Utah began enforcing its 0.05% BAC law in 2019. The study found that alcohol-related traffic fatalities declined more in Utah than in surrounding states after the law took effect. Earlier federal research by the National Highway Traffic Safety Administration (NHTSA) also reported encouraging results during the first full year of Utah’s law. This includes nearly a 20% reduction in fatal crash rates, an 18% reduction in traffic fatalities, and no substantial increase in overall DUI arrests. Public awareness of the lower limit increased dramatically, and many drivers reported changing their behavior by arranging rides before drinking. These findings suggest the law may work primarily by discouraging people from driving after drinking rather than by dramatically increasing arrests.
Arguments for and against a change in BAC limits
Supporters argue these findings show that lowering Colorado’s DUI BAC limit to 0.05% could save lives by encouraging safer choices before drivers get behind the wheel. They point out that even moderate alcohol consumption can impair judgment, reaction time, and decision-making.
Critics caution that Utah may not be a perfect model for Colorado. Utah consistently has one of the nation’s lowest rates of alcohol consumption and binge drinking, while Colorado’s drinking patterns are significantly higher. Because of those differences, some researchers question whether Colorado would experience the same safety benefits. Other published studies (e.g., Olson & Adams, 2026; Portillo, Sugiarto & Willardsen 2024), have reached more cautious conclusions, finding little or no statistically significant reduction in alcohol-related fatal crashes after accounting for other factors. So it appears that the scientific literature remains mixed even though the most recent CSU study favors the lower limit.
Colorado’s DUI laws have evolved over several decades. The state adopted modern DUI and DWAI statutes in the early 1980s, established a 0.10% per se DUI limit in 1983, lowered the limit to 0.08% in 2004 after that was essentially federally mandated, and continues to enforce a separate DWAI offense beginning above 0.05%. Commercial drivers and drivers under 21 are already subject to lower BAC thresholds (0.04 and 0.02, respectively).
For anyone facing DUI or DWAI charges, these discussions are important because they could reshape how impaired-driving cases are prosecuted. If the DUI limit were lowered to 0.05%, drivers who would have faced DWAI allegations could instead face DUI charges based solely on the driver’s BAC, without prosecutors needing to prove actual impairment at that lower level.
Whether the law changes or not, the best way to avoid a DUI is clear: if you’ve been drinking, don’t drive. The cost of a ride-share is infinitely better than what could happen if you drive after drinking. If you have been arrested for DUI or DWAI in Colorado, however, experienced legal representation is critical. Every case involves unique facts, including the legality of the traffic stop, roadside testing, chemical testing procedures, and constitutional issues that may affect the outcome.
Contact Churchill Criminal Defense for Questions about DUI charges in Colorado
If you have questions about DUI laws or your DUI case, contact Colorado DUI attorney Kevin Churchill at Churchill DUI Defense to discuss your options and protect your rights. He is an experienced Colorado DUI attorney, practicing in the front range for over 20 years.