Smartphone Breathalyzers Lower Risk of DUI, Say 84 Percent of CDOT Program Participants

STATEWIDE—Over the summer, the Colorado Department of Transportation (CDOT) distributed smartphone breathalyzers to 225 randomly-chosen participants in the Denver metro area. In exchange, participants agreed to provide feedback to CDOT on their experience. At the end of the program, 84 percent of participants agreed that owning a smartphone breathalyzer lowered their risk for a DUI/DWAI.

Similarly, 82 percent agreed anyone who regularly drinks should own a breathalyzer. Before receiving the breathalyzers, 79 percent believed they might have previously driven while above the DUI limit, compared to the program's final survey, in which participants were asked about their behavior since receiving and using breathalyzers; only 12 percent of participants reported that they may have driven impaired.

Program participants gathered to share their experience with the breathalyzers.

I'm encouraged that so many participants found the smartphone breathalyzers effective in helping them think more about how easy it is to approach the DWAI and DUI limits after only one or two drinks," said Sam Cole, CDOT communications manager. "It's not only CDOT's responsibility to educate Colorado drivers about the dangers, laws and consequences of impaired driving, but also introduce them to resources that help them make smart decisions while drinking."

CDOT partnered with BACtrack, a manufacturer of smartphone breathalyzers, to gain insight about drinking habits—especially related to drinking and driving, among Coloradans. Participants used the devices throughout the summer and completed surveys about their experience, recording a total of 4,823 blood alcohol concentration (BAC) readings—an average of 21 readings per participant. The average BAC level was 0.087 percent, above Colorado's ).08 percent BAC limit for a DUI.

The initial participant survey revealed some concerning realities:

  • 92 percent knew the 0.08 BAC limit for a DUI, but only 47 percent were aware of Colorado's driving while ability impaired (DWAI) BAC limit of 0.05 percent.
  • 79 percent of participants indicated they might have driven a car while above the legal driving limit.
  • 92 percent thought they had been a passenger with a driver above the legal limit.

Not surprisingly, Fridays and Saturdays saw the highest number of breathalyzer readings, with average BACs of 0.082 percent and 0.096 percent, respectively. While Sundays received about half as many readings, Sunday recorded the highest average BAC of any day of the week at 0.101 percent.

More BAC data trends:

Average BAC by time of day

  • Midnight – 6 a.m.: 0.115 percent
  • 6 a.m. – Noon: 0.061 percent
  • Noon – 6 p.m.: 0.075 percent
  • 6 p.m. – Midnight: 0.086 percent

Average BAC by Age

  • 21 – 30: 0.092 percent
  • 31 – 40: 0.088 percent
  • 41 – 50: 0.076 percent
  • 51 – 60: 0.067 percent
  • 61+: 0.047 percent

Results recorded the highest BAC averages of any timeframe from midnight to 6 a.m., at 0.115 percent. This indicates that early weekend mornings—a time when drinkers are leaving bars and faced with the decision of how to get home—pose a higher potential for impaired driving.

The BACtrack breathalyzers were distributed at CDOT headquarters and Call to Arms Brewery in Denver. Most BAC readings were logged locally, though some came from outside of Colorado when participants traveled to other states.

Participants shared the following testimonials about their experience in the program:

  • The breathalyzer provides me an extra line of defense in the battle of convincing my friends not to drive after drinking, giving me hard, undeniable evidence of their impairment level."

  • "I have noticed that I am over the legal limit much more than I thought. Even the next day after drinking, I like to test it and have found my BAC to be over 0.04. Scary! The program has been very eye-opening.:"

  • "A friend was leaving my house after a late night out and we used the device to determine whether he should drive or call for a ride. He thought he was all right to drive, but blew a 0.077, so he took an Uber instead."

Smartphone breathalyzers are a tool to help drinkers make better decisions, but CDOT recommends always having a safe ride planned before you start drinking. CDOT's newly enhanced "R-U-Buzzed" smartphone app is another resource to help avoid driving impaired. R-U-Buzzed works by estimating users' BAC levels based on the interaction of weight, gender, time drinking and alcohol consumed. The app features an easy-to-use, one-screen interface that allows users to quickly update or begin a new reading in an instant. The app then calculates the BAC level, and shares safety information about impairment and Colorado's laws.