Colorado Following-Distance & Headlight Rules
How far back to follow another vehicle, when to dim high beams for oncoming and following traffic, and the move-over law for emergency vehicles.
- Following-distance rule
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Use the three-second rule in normal conditions: watch the vehicle ahead pass a fixed reference point (sign, mile marker, utility pole), then count 'one-thousand-one, one-thousand-two, one-thousand-three.' If you pass the reference point before finishing the count, you are following too closely. Increase the following gap in rain, snow, ice, fog, heavy traffic, at night, or on unfamiliar roads, and any time stopping distance is likely to grow. A typical passenger car at 55 mph needs about 200 feet to stop in ideal conditions.
Source: Colorado Driver Handbook (2023), Safe Driving Tips, Three-second rule; Speed, Stopping distance
- Dim high beams within (ft) — oncoming
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500
- Dim high beams within (ft) — following
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200
- Headlight requirements
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Colorado law requires headlights to be on from sunset to sunrise and whenever visibility is less than 1,000 feet. Parking lights alone do not satisfy the requirement. Any vehicle parked alongside the roadway, attended or not, must have its parking lights on during the same conditions. Use low beams and front fog lights, if equipped, to improve visibility in fog or heavy rain; high beams reflect off the moisture and reduce sight distance. Dim high beams within 500 feet of an oncoming vehicle and within 200 feet of a vehicle you are following. Running low beams or daytime running lights at all times is recommended.
Source: Colorado Driver Handbook (2023), Night Driving and Weather sections
- Motorcycle following rule
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The Colorado Driver Handbook does not give a numeric following distance specific to motorcycles. It instructs drivers to use extra caution around motorcyclists and to increase following distance because motorcycles are smaller and harder to see, can stop more quickly than expected, may move within their lane to avoid road defects or debris, and can be moved out of lane by strong winds. The general three-second following rule still applies and should be extended in poor conditions or when following any smaller, less visible road user.
Source: Colorado Driver Handbook (2023), Sharing the Road, Motorcycles; Safe Driving Tips, Three-second rule
- Cyclist safe-passing rule
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Colorado requires drivers to give bicyclists a minimum of three feet of clearance between the outermost part of the vehicle (including mirrors, trailers, or other projections) and the bicyclist when passing or overtaking. The three-foot rule applies on all roadways, whether or not a 'Pass 3 Ft Min' sign is posted. When three feet cannot be given, slow down and stay behind the bicyclist until it is safe to pass. A driver may briefly cross a solid yellow line, including a double solid yellow line, to provide the three feet when there is no oncoming traffic and a clear view ahead. Give more than three feet on rural roads, when driving a larger vehicle, or in windy conditions, because wind blasts from passing vehicles can knock a bicyclist off the bike.
Source: Colorado Driver Handbook (2023), Pavement Markings (yellow lines), Passing, and Bicyclists sections
- Move-over law (stopped emergency vehicles)
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When approaching a stopped emergency vehicle displaying flashing red, blue, white, or yellow lights, move over one lane if it is safe to do so. If the road has only one lane in your direction or you cannot change lanes safely, slow down to 25 mph if the posted speed limit is 45 mph or less, or to 20 mph below the posted limit if the posted limit is above 45 mph. The same move-over and slow-down duty applies to maintenance and service vehicles displaying flashing yellow and blue warning lights and to tow trucks. It is illegal to pass an authorized snow plow working in a staggered formation with other plows.
- Defensive-driving framework
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The Colorado Driver Handbook teaches defensive driving as a set of habits rather than a named system. Drivers are told to scan ahead, to the sides, and behind every five to eight seconds, to keep a three-second following gap under normal conditions, and to adjust speed to weather, traffic, and road conditions. The book does not adopt a formal acronym such as SIPDE, IPDE, or Smith System.
Source: Colorado Driver Handbook (2023), Safe Driving Tips, p. 18
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