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Most-missed Colorado DMV rules
These are the numbers and rules that trip up new drivers most often on the real Colorado knowledge test. Every fact below comes from our free Colorado DMV practice test question bank, which has 180 questions across 8 topics.
Speed limits
- Colorado's default statutory limit for business districts is 25 mph when no other sign is posted.
- Colorado's statutory default for residential districts is 30 mph absent other posted signs.
- The handbook lists 65-75 mph as the range for designated rural interstates/highways.
- The handbook notes that fines are doubled in work zones, the same as in school zones.
- The handbook lists 55 mph as the default for urban interstates/highways absent other posted limits.
- School zones commonly have reduced, clearly posted speed limits, and fines for speeding in them are often doubled.
- Exceeding by 25 mph or more is a Class 2 misdemeanor, upgraded to a Class 1 misdemeanor in a construction zone.
Right of way
- Per the handbook, right-of-way is never automatically given even with a green light; you must yield to those already in the intersection.
- Pedestrians always have right-of-way at intersections and crosswalks under Colorado rules.
- Vehicles merging or turning across a designated bike lane must yield to bicyclists already there.
- For simultaneous arrivals at an uncontrolled or four-way stop, the vehicle on the left must yield to the vehicle on the right.
- The vehicle that arrives first at the stop is entitled to go first.
- Colorado's mountain-road rule requires the descending (downhill) vehicle to yield and back up for the ascending (uphill) vehicle, unless backing up is more practical for the uphill driver.
- Emergency vehicles always get right-of-way over other traffic in Colorado.
- Drivers entering a roundabout must yield to traffic already circulating inside it.
- When on sidewalks or crosswalks, bicyclists are treated with pedestrian right-of-way rules.
- Handbook rules require yielding to vehicles already in an intersection you are approaching, regardless of signal color.
- Pedestrians always have the right-of-way at intersections and crosswalks, regardless of the traffic signal.
- Do not cut through or break up a funeral procession. Slow down, be patient, and let it pass. Cutting between the vehicles is unsafe and often illegal.
- At an uncontrolled intersection, slow down and yield to any car already in the intersection or approaching from your right.
- A left-turning vehicle must yield to oncoming through traffic and to pedestrians. Only turn when the gap is safe.
- When entering a roundabout, yield to traffic already circulating and travel counterclockwise. Exit at your street; do not stop in the middle of the circle.
- At a T-intersection, traffic on the road that ends must yield to traffic on the through road that continues.
- A round green light allows a left turn but does not give you the right of way. Pull into the intersection, yield to oncoming through traffic and pedestrians, then turn when there is a safe gap.
Alcohol and DUI
- Colorado sets the DUI per se threshold at 0.08% BAC for drivers 21 and older.
- DWAI covers BAC from 0.05% up to 0.08%, reflecting impairment to the slightest degree.
- CDL holders face a stricter 0.04% BAC threshold in Colorado.
- Under-21 drivers face mandatory revocation and other consequences at just 0.02% BAC, far below the adult DWAI threshold.
- The under-21 threshold (0.02%) is stricter and lower than the general adult DWAI threshold (0.05%).
- From lowest (most restrictive) BAC to highest: under-21 zero tolerance at 0.02%, then CDL at 0.04%, then DWAI starting at 0.05%, then full DUI at 0.08%.
- A chemical test showing a BAC of at least 0.15% can trigger a persistent drunk driver classification with enhanced penalties.
- A first offense with a BAC test of at least 0.08 carries a 9 month administrative suspension, rising to 12 and 24 months for second and third offenses.
- A first DUI conviction carries a 9 month suspension and 12 points against the driver's record.
- A DWAI conviction alone carries no automatic suspension but adds 8 points to the driver's record.
- A first UDD offense for a driver under 21 with a BAC of at least 0.02% but under 0.05% carries a 3 month suspension and 4 points.
- A first DUI (or DUI per se) carries 5 days to 1 year jail, a $600-$1,000 fine, and 48-96 hours of public service.
- With 3 or more prior DWAI/DUI convictions, the offense becomes a Class 4 felony punishable by 2 to 6 years imprisonment and 3 years mandatory parole.
- A first refusal under Colorado's Express Consent law results in a one-year license revocation and a Persistent Drunk Driver designation.
Signals and markings
- According to Colorado guidance, a bike lane's protections carry through an intersection even if the lane markings aren't painted there.
- A steady yellow light warns that the signal is about to change to red, so drivers should slow and prepare to stop if it is safe to do so.
- A solid yellow line on your side of the center marking indicates passing is prohibited from that direction due to limited sight distance or other hazards.
- On a plain green light, a left-turning driver must yield to oncoming traffic and pedestrians before completing the turn.
- The manual requires dimming high beams for oncoming traffic to avoid blinding other drivers.
- At uncontrolled intersections, drivers must yield to vehicles that are already in the intersection.
- A solid yellow line on your side of the centerline means passing is not permitted there, usually due to reduced visibility or other roadway hazards.
- A flashing red signal is treated the same as a stop sign: come to a full stop, then proceed only when it is safe.
- The truck apron is a raised, paved area only meant for large truck wheels; ordinary vehicles should never drive on it.
- A flashing yellow signal warns drivers to slow down and proceed carefully, unlike a solid red which requires a full stop.
- A flashing yellow signal warns drivers to slow down and proceed carefully, rather than requiring a full stop.
- A solid yellow line on your side of the centerline indicates that passing is prohibited from that side of the road.
- A driver turning left must yield the right-of-way to all oncoming traffic, including bicyclists, before completing the turn.
- A flashing yellow light warns drivers to slow down and proceed carefully, unlike a flashing red which requires a full stop.
- A bike box lets cyclists position ahead of traffic; drivers must stop behind the box rather than within it.
- A flashing yellow signal is a caution indicator meaning drivers may proceed but should do so carefully.
- A dashed yellow centerline indicates passing is permitted on that side, provided it can be done safely and there is no oncoming traffic conflict.
- A steady red light requires a full stop; cross traffic has the right of way until the light changes.
- A green arrow grants a protected right of way to complete that turn without yielding to opposing traffic.
- A dashed yellow centerline indicates passing is generally allowed on that side when it is safe to do so and no other restriction applies.
- A flashing yellow signal warns drivers to slow down and proceed carefully through the intersection, unlike a dark signal which is treated as a stop.
- A flashing yellow signal warns drivers to proceed through the intersection with caution rather than requiring a full stop.
- A law enforcement officer's directions override traffic signals, so drivers must obey the officer even if it means stopping on a green light.
- A dashed yellow line means passing is allowed when there is a safe gap in oncoming traffic, unlike a solid yellow line.
- A flashing yellow light means slow down, look, and proceed carefully. It does NOT require a full stop the way a red light or STOP sign does.
- A flashing hand or countdown means do NOT start crossing. If you are already in the crosswalk, keep going and finish crossing safely.
- A steady DON'T WALK hand prohibits starting to cross. Only a WALK signal or walking-person symbol allows you to begin crossing.
- Always signal continuously through a turn or lane change even when you see no other cars, because pedestrians or cyclists may be near. Cancel the signal after you finish.
- A green downward arrow means the lane is open for you to use. A red X above the lane means it is closed and you may not drive in it.
- Double solid yellow lines separate opposing directions and prohibit passing. You may only cross them for a permitted left turn or a legal U-turn into an intersection or driveway.
- A broken yellow line on your side of the lane allows passing when it is safe. The solid line on the opposite side means that direction may not pass.
- White lines separate lanes going the same direction. A solid white line means stay in your lane and avoid changing lanes, while a broken white line lets you change lanes when safe.
- A two-way center left-turn lane is only for preparing to turn left or merging into traffic. You may not use it to drive straight through or to pass.
Safe driving
- The handbook references traction/chain law requirements tied to Colorado's mountain and winter driving conditions, pointing drivers to CDOT for details.
- Scanning further ahead gives drivers earlier warning of hazards, slowing traffic, or obstacles, allowing more time to react safely.
- The safe response to a skid is to ease off the gas and steer smoothly in the direction you want to travel, rather than braking hard or overcorrecting.
- Since entering roundabout traffic must yield to vehicles already circulating, slowing down and watching for a safe gap is the correct approach.
- The manual requires yielding to pedestrians, cyclists, and others still clearing the intersection even if you'd otherwise have priority.
- Posted speed limits are for ideal conditions; drivers should reduce speed further and increase following distance in poor weather like heavy rain or fog.
- A 3 to 4 second following distance gives drivers enough time to react and brake safely under normal conditions.
- The manual requires headlights to be on whenever visibility is under 1,000 feet.
- Advisory speed plates on curve warning signs indicate a safe reduced speed that drivers should slow to before entering the curve.
- On undivided roads, traffic in both directions must stop for a school bus with flashing red lights and an extended stop sign until it resumes moving.
- General right-of-way practice, reflected in the manual, is that the first vehicle to arrive and stop proceeds first; simultaneous arrivals yield to the right.
- The manual explains posted limits are for ideal conditions, and driving that speed in bad conditions can still be cited as too fast for conditions.
- General safe-driving principles call for maintaining an adequate following distance that increases with speed and worsening conditions to allow safe stopping.
- Wet roads increase stopping distance, so drivers should slow down and add extra space to compensate for reduced traction.
- Handbooks generally recommend a multi-second following distance that should be increased in bad weather, at higher speeds, or in heavy traffic.
- Work zones are posted at least 10 mph under the normal maximum speed specifically to protect workers and should always be observed.
- Drivers must yield to emergency vehicles with active lights and siren by safely moving aside, not stopping in the travel lane.
- Drivers must stop for a school bus with flashing red lights and remain stopped until the lights stop flashing, protecting children crossing.
- Safe driving practice calls for maintaining enough distance behind the vehicle ahead to react and stop safely if it brakes suddenly.
- Because posted speed limits assume ideal conditions, the handbook advises reducing speed in rain and other hazardous conditions.
- With a tailgater, open up more space in front of you so you can brake gradually instead of suddenly. Do not brake to retaliate and do not race away.
- Strong crosswinds can push your car out of its lane. Hold the wheel firmly with both hands, slow down, and be ready for sudden gusts.
- Do not engage. Avoid eye contact, do not brake in retaliation, let them pass, and leave a safe distance between you and that car.
- Horses and livestock spook easily. Slow down, do not honk or rev your engine, and pass very slowly with plenty of room so you do not startle them.
- When you see a hazard developing ahead, cover the brake and plan an escape route so you can react faster if you have to stop.
- In a skid, ease off the gas or brake and steer gently in the direction you want the front of the car to go. Slamming the brakes makes the skid worse.
Road signs
- The Colorado handbook doesn't publish one statewide school-zone number; the exact figure is posted locally on signs at each site.
- STOP (R1-1): full stop at the line or crosswalk even when empty; yield, then proceed.
- YIELD (R1-2): give up the right-of-way; slow and be ready to stop.
- DO NOT ENTER (R5-1): entry prohibited; common at freeway off-ramps and one-way streets.
- WRONG WAY (R5-1a): you have entered opposing traffic. Pull over safely and turn around when possible.
- ONE WAY (R6-1): all traffic flows in the arrow's direction.
- NO U-TURN (R3-4): no U-turns at this location. This is not a no-left-turn sign (a different arrow shape) or a no-passing sign (a different shape and color entirely).
- NO LEFT TURN (R3-2). A red circle-and-slash always bans the pictured movement.
- NO RIGHT TURN (R3-1): no right turns, including on red. Going straight is still fine since the sign only bans the right-turn movement; parking is unrelated to this sign.
- White/black = regulatory. Speed Limit is the legal max in ideal conditions; drive slower when conditions are bad (Basic Speed Law).
- KEEP RIGHT (R4-7): a median or obstruction is ahead; keep to its right.
- The crossbuck (R15-1) stands at the tracks and legally works like a YIELD sign: slow, look both ways, be ready to stop.
- Advance warning (W10-1): tracks ahead. Slow down, look, and listen.
- School (S1-1): school zone or crossing. Slow down and watch for children; obey the posted reduced school-zone speed limit, which varies by state.
- Pedestrian crossing (W11-2): crossing ahead; slow and be ready to stop.
- Signal ahead (W3-3): an intersection signal is coming, useful when it hides behind a curve.
- Stop ahead (W3-1): a stop sign is coming (often obscured); start slowing now.
- Merge (W4-1): traffic joins ahead. Adjust speed and position to let them in safely.
- Lane ends (W4-2): merge early; zipper-merge when traffic is heavy.
- Two-way traffic (W6-3): you are leaving a one-way road; keep right.
- Divided highway begins (W6-1): directions separate around a median; always keep right of it.
- Slippery when wet (W8-5): slickest in fresh rain. Slow down, keep distance, steer smoothly.
- Curve (W1-2): slow BEFORE the curve; do not brake in the middle of it.
- Turn (W1-1): sharper than a curve; slow down hard, follow the advisory plaque.
- Winding road (W1-5): consecutive curves; hold a steady lower speed throughout.
- Crossroad (W2-1): an intersection ahead with traffic entering from both sides. Hospital signs are blue with an H.
- NO PASSING ZONE (W14-3): unique pennant shape, posted on the LEFT side, marks where passing becomes illegal.
- The circular yellow sign shape is specifically reserved in the national sign system for advance railroad crossing warnings.
- The handbook's statutory speeds apply only when no other limit is posted, meaning posted signage takes precedence.
- Speed limit signs are standard rectangular white regulatory signs, distinct from the diamond-shaped yellow warning signs.
- The five-sided pentagon shape is reserved specifically for school-related warning signs, distinct from all other warning sign shapes.
- The handbook instructs drivers at yield signs to slow down and yield to vehicles already in the intersection or approaching.
- A YIELD sign requires slowing down and stopping only if needed to give way to traffic or pedestrians on the intersecting road.
- An inverted triangle is the standard shape used for yield signs, instructing drivers to slow and give way to other traffic.
- A circular sign with a diagonal slash through it is used nationally to show that a prior restriction (like a speed limit) no longer applies.
- Yellow warning signage in this context provides an advisory safe speed recommendation for hazards like curves, distinct from a legally binding limit.
- Diamond-shaped yellow signs are warning signs, alerting drivers to hazards like curves, merges, or crossings ahead.
- The manual specifies reduced speed limits apply at locations marked with a School Crossing sign when children are present.
- Diamond-shaped yellow signs are warning signs, alerting drivers to hazards or changes in road conditions ahead.
- The eight-sided red STOP sign requires a complete stop at the marked line or intersection before proceeding when safe.
- Drivers must stop at the marked line or crosswalk, or at the edge of the intersection if there is no marking, before proceeding.
- The eight-sided shape is reserved exclusively for stop signs so drivers can recognize it even if the sign face is obscured.
- School zone warning signs signal drivers to reduce speed and watch for children, consistent with the guide's emphasis on adjusting speed for conditions and hazards.
- The manual specifically calls out School Crossing signs with children present as requiring reduced speed.
- At a yield sign, drivers must slow or stop as needed to let crossing or oncoming traffic clear before proceeding safely.
- The yellow pennant-shaped sign marks the start of a no-passing zone. It usually appears along with a solid yellow line on the pavement.
- A yellow diamond-shaped sign is a WARNING sign, alerting you to a hazard or change ahead such as a curve, intersection, or school, so you slow down.
- A white rectangular sign with black lettering is a REGULATORY sign stating a law you must obey, such as speed or direction of travel.
- An orange sign marks a construction or roadwork zone. Slow down and watch for workers and shifting lanes.
- A blue sign points to driver services such as gas stations, food, lodging, or hospitals.
- A green sign is a GUIDE sign, showing directions, distances, and the names of exits or places.
- A red circle with a slash means the action shown is PROHIBITED, such as no turn or no U-turn at that spot.
Laws and paperwork
- The Move Over law requires drivers to change lanes away from the stopped vehicle when it is safe to do so.
- The law is broad, covering any stationary vehicle with hazard lights flashing, not just police or emergency vehicles.
- Colorado requires headlights from sunset to sunrise as well as whenever windshield wipers are in use due to rain, snow, or similar precipitation.
- Colorado's curfew law restricts newly licensed minors from driving between midnight and 5:00 a.m. unless an exception applies.
- Colorado requires minors under 18 to hold a learner's permit for at least 12 months before applying for a license.
- HB24-1021 will require minors ages 15-17 to complete a 30-hour driver education course starting January 1, 2027, replacing the current option to choose a shorter awareness program.
Emergencies
- The handbook prohibits passing a working snow plow with flashing yellow lights, especially plows working in tandem or staggered formation.
- Multiple plows working together should be treated as a unit, and passing while they're actively working is illegal.
- On a road where you cannot move over a full lane, Colorado's Move Over law requires slowing substantially, at least 20 mph below the posted limit.
- Move over laws generally require drivers to change lanes away from a stopped emergency or hazard vehicle when safe, or otherwise slow down.
- Drivers must yield to emergency vehicles by pulling over to the right side of the road, clear of intersections, and stopping until the vehicle passes.
- The manual notes you only have right of way if the other vehicle isn't already in the intersection, meaning a vehicle already there should be allowed to clear first.
- Standard guidance for hydroplaning is to ease off the gas and avoid sudden braking or steering, letting the tires regain contact with the road.
- Drivers must yield to emergency vehicles by pulling to the right and stopping, while making sure not to block the intersection.
- Pumping the brakes can rebuild some pressure, and downshifting uses engine braking to help slow the vehicle safely before using the parking brake carefully.
- On typical two-lane roads, traffic in both directions must stop for a loading school bus; the opposite-direction exception applies only on wider divided highways.
- The manual requires drivers to stop for a school bus with flashing red lights from either direction, unless a physical median or barrier separates the roadways.
- Steering gently in the direction you want to go while easing off the accelerator helps regain control during a skid.
- Drivers must yield to emergency vehicles by pulling over to the right and stopping until the vehicle has passed.
- On divided highways of 4+ lanes, drivers should move over a lane away from a stopped emergency vehicle when it can be done safely.
- Sudden hard braking or sharp steering after a blowout can cause loss of control; easing off the gas while holding a straight line is safer.
- Drivers should move to the right and yield the roadway to approaching emergency vehicles with active lights and sirens, stopping if necessary to let them pass safely.
- Drivers must yield right-of-way to emergency vehicles operating with active lights and siren.
- Move Over laws require drivers to move over or slow down for any stopped vehicle with warning lights activated, to protect people near the roadway.
- The Move Over Law has escalating consequences: a basic violation carries a modest fine and point penalty, a violation causing a crash carries a higher fine, and one causing death or serious injury carries the harshest penalty.
- When changing lanes is not safe, the Move Over Law still expects drivers to reduce speed and use caution passing the stopped vehicle.
- Regardless of whether a crossing has gates or signals, drivers must never attempt to beat a visible train and must stop and wait for it to clear.
- Hazardous materials carriers must stop at every railroad crossing regardless of visible train activity, so drivers behind them should expect and safely wait through this stop.
- Drivers must move over a lane or slow down when passing any stationary vehicle with flashing lights on the roadside, not just law enforcement vehicles.
- If your car catches fire or smells like burning, pull over, shut off the engine, and get everyone away. Do not open the hot hood, since the rush of air will make the fire flare up.
- If the gas pedal sticks, shift to Neutral to cut the power, then brake and steer to the shoulder. Only turn off the engine after you have fully stopped, so you do not lose power steering.
Signs
Sign shape and color carry meaning before you even read the words. A red octagon always means stop, a red-bordered triangle pointing down means yield, and yellow diamonds warn of a hazard ahead. For every sign image used in our practice test, with the exact meaning and explanation, see the full road sign glossary.
Keep studying
This cheat sheet is a summary, not a substitute for practice. Test yourself with the free Colorado DMV practice test, which explains the reasoning behind every answer, or see Colorado DMV facts and fees before test day.