To report a drunk driver in Colorado, call 911 if the vehicle poses an immediate danger, or dial *CSP (*277) from any cell phone to reach the Colorado State Patrol’s impaired-driver line. Both calls are free, both reach a dispatcher who can send officers to intercept the car, and Colorado law specifically allows you to use your phone behind the wheel to make them.
What to Tell the Dispatcher
When the dispatcher answers, say you are reporting a suspected impaired driver and give three things:
- The exact location, including the road name and the direction the vehicle is heading.
- A description of the vehicle: color, make, model, and license plate if you can read it safely.
- What you saw the driver doing.
Specifics matter. “A blue Honda Civic, northbound I-25 near mile marker 217, weaving across both lanes” gives officers something to act on. “A blue car driving weird on I-25” does not. The dispatcher may ask you to stay on the line and keep updating the vehicle’s position and behavior, especially on a highway where the car can cover miles before a patrol unit catches up.
Once officers find the vehicle, they look for their own signs of impairment before pulling it over. Courts generally expect officers to corroborate details from a caller’s report and observe indicators themselves when possible, which is another reason accurate information from your call carries weight.
Yes, You Can Use Your Phone for This Call
Colorado’s hands-free law, in effect since 2024, prohibits using a mobile phone while driving. It also carves out explicit exceptions for contacting a public safety entity and for emergencies, and the statute defines emergencies to include reporting someone driving in a reckless, careless, or unsafe manner.
You can legally pick up your phone and dial 911 or *277 while driving to report an impaired driver. No hands-free violation applies. A first violation of the hands-free law in ordinary circumstances carries a $75 fine and two license points, but this call is not a violation. If you have a passenger, let them handle the call. If you are alone, use speakerphone or a hands-free accessory and keep your eyes on the road.
Don’t Follow the Vehicle
The Colorado State Patrol says this directly on its reporting page: do not follow or pursue the vehicle. Tailing an erratic driver puts you in the path of the collision you are trying to prevent. Give the dispatcher the last location and direction of travel and let officers take over.
If you happen to be heading the same way, keep a wide following distance. Don’t flash your headlights, honk, or try to signal the driver. An impaired person can react unpredictably to sudden stimuli.
When Driving Behavior Is Worth Reporting
You don’t need to be sure the driver is drunk. You need to be concerned about the driving. The National Highway Traffic Safety Administration lists cues that officers use to spot impaired drivers, and most are visible from another car:
- Weaving within a lane, straddling the center line, drifting toward the shoulder or oncoming traffic, or swerving to correct.
- Wide or sweeping turns, nearly striking vehicles or objects, turning from the wrong lane.
- Rapid acceleration or braking for no reason, driving more than 10 mph below the limit, jerky stops well before an intersection.
- Driving without headlights after dark, slow responses to signals, stopping in a travel lane, driving the wrong way on a one-way street.
- Following too closely or making unsafe lane changes.
No single cue proves impairment. Medical conditions such as low blood sugar, severe allergic reactions, and anxiety attacks can look similar. You don’t have to diagnose the cause. If someone is driving dangerously enough to put others at risk, the behavior is worth reporting whatever is behind it.
Good-Faith Reports Are Protected
Colorado law shields people who report suspected crimes in good faith. Under C.R.S. § 18-8-115, anyone with reasonable grounds to believe a crime is being committed and who reports it to authorities is protected from civil liability so long as the report was made in good faith. You don’t have to be right about the driver being intoxicated. If the behavior genuinely concerned you, your report is protected even if the driver turns out to be sober.
Knowingly false reports are a separate matter. Under C.R.S. § 18-8-111, reporting a crime to law enforcement that you know did not happen is a class 2 misdemeanor, punishable by up to 120 days in jail and a fine of up to $750. The statute turns on the word “knowingly,” and it targets fabricated reports, not honest mistakes.
What Happens After You Hang Up
You won’t get a call back telling you whether the driver was stopped or arrested. Privacy rules keep dispatchers from sharing that with callers. Your part ends when law enforcement has what they need to act.
Reporting an Impaired Boater
Impaired operation on Colorado’s lakes and reservoirs is just as illegal as on the road, and the reporting path is a little different. Call 911, or hail the U.S. Coast Guard on marine VHF Channel 16. Colorado Parks and Wildlife officers also have authority to stop and test boaters for impairment on state waters.