Colorado Driving Laws 2026: Speed Limits, DUI BAC Limits and Road Rules for the Written Test

What are the legal speed limits in Colorado when no sign is posted? Colorado statutory limits include 20 mph on narrow, winding mountain highways or blind curves, 25 mph in business districts, 30 mph in residential districts, 40 mph on open mountain highways, 55 mph on other open highways, and 65 mph on surfaced four-lane interstate or expressway highways unless another limit is posted; the maximum posted speed in Colorado is 75 mph. The DMV knowledge test is 25 questions with a 80% pass requirement. Colorado DUI: 0.08% is per se DUI; a BAC between 0.05% and 0.07% is DWAI (Driving While Ability Impaired) and also a criminal offense, a unique distinction most states do not have. Headlights are required from sunset to sunrise or whenever visibility is less than 1,000 feet.

1. Speed Limits in Colorado

Colorado sets speed limits by zone and road type, and mountain highways get their own tiers. On narrow, winding mountain highways or blind curves, 20 mph is the statutory limit. Colorado allows posted limits up to 75 mph, but the statutory limit on surfaced four-lane interstates or expressways is 65 mph unless a different limit is posted. Heres the full statutory breakdown when no sign is posted:

Key test point: Colorados mountain roads are unforgiving, even if you are at the posted limit, black ice, sudden snowfall, or reduced visibility on a blind curve requires immediate speed reduction. Work zones also carry reduced posted limits that are strictly enforced. Driving slower than the minimum posted speed is also a traffic violation.

2. Right-of-Way: Who Goes First

Colorados knowledge test hits right-of-way hard, especially yield-to-uphill rules on mountain roads and pedestrian crossings. Remember: right-of-way is always yielded, never claimed.

Colorado mountain-road right-of-way: On a narrow mountain road where two vehicles cannot safely pass, the vehicle traveling downhill should yield to the vehicle traveling uphill, unless the downhill vehicle has a wider pull-out available.

4-way stop (all arrive at once)

Driver to the right

4-way stop (one arrives first)

Driver who arrived first

Roundabout / traffic circle

Vehicles already inside the circle

Emergency vehicles (lights/siren)

Emergency vehicle, pull to the right and stop

Pedestrians in crosswalk

Pedestrians always

T-intersection (no signs)

Through road traffic; drivers on the dead-end must yield

Yield sign

Cross traffic and pedestrians always

Merging onto a highway

Traffic already on the highway

3. Turns & Signal Laws

Colorado requires 100 feet of continuous signaling in urban areas and 200 feet on four-lane highways over 40 mph. Right turns on red are generally allowed after a full stop. Heres how every turn scenario breaks down under Colorado law:

Right turn on red

Permitted after a full stop unless a sign prohibits it. Yield to pedestrians and cross traffic.

No right turn on red

When posted, you must wait for a green light before turning right.

Left turn on red

Only allowed from a one-way street onto another one-way street, after a full stop.

Left turn from two-way street

Start from the left lane; end in the left lane of the cross street.

Right turn

Stay as close to the right curb as possible; end in the right lane.

U-turns

Legal when the movement can be made safely without interfering with traffic and no sign prohibits it. Do not make a U-turn on a curve or near the crest of a grade when approaching drivers cannot see your vehicle from far enough away to avoid danger.

4. Lane Rules & Line Markings

On Colorados mountain corridors, lane discipline is critical, passing on a blind curve is illegal and potentially fatal. On urban freeways through Denver and Colorado Springs, center turn lane and carpool rules apply. Heres the complete breakdown tested on the Colorado DMV exam:

Center turn lane (CTSL)

Used only when preparing for or making a left turn from or into the roadway, or when preparing for or making a U-turn when otherwise permitted by law; not for through travel.

Solid white line

Do not cross; marks the edge of the road or a lane that should not be changed.

Solid yellow line (your side)

No passing allowed.

Broken yellow line

Passing allowed when safe.

Solid + Broken yellow centerline

Passing allowed only on the broken-line side.

5. Passing Another Vehicle

On two-lane mountain highways through the Rockies, passing is one of the most dangerous decisions a driver makes. Colorado law sets firm rules on when and where it is illegal, and the consequences of getting it wrong at altitude are severe:

• Only pass on the left, using the oncoming lane, when it is safe and legal.
• Do not pass within 100 feet of an intersection, railroad crossing, bridge, or curve where your view is limited. Look for the No Passing Zone pennant sign.
• The vehicle being passed must not speed up while you are overtaking.
• Passing a bicyclist: Colorado requires at least 3 feet of clearance between your vehicle, including mirrors, and the bicyclist. If you cannot provide that space safely, wait until it is safe to pass.
• Return to your lane before coming within 200 feet of oncoming traffic. When you can see both headlights of the vehicle you passed in your rearview mirror, it is safe to return to your lane.
• Never pass a stopped school bus with flashing red lights, this applies in both directions on undivided roads.
• You may pass on the right only when the vehicle ahead is turning left and there is a usable lane to the right.

6. Following Distance

On Colorados mountain highways, stopping distances are dramatically longer, a car at 55 mph takes about 200 feet to stop under normal conditions, and far more on ice or wet roads. The 3-second rule is your floor under ideal conditions. In the mountains, double it.

7. School Buses & Emergency Vehicles

Colorado law requires you to stop at least 20 feet from a school bus when its red lights are flashing. This is directly tested on the Colorado knowledge exam, know the distance, know the exceptions.

School Buses

• When a school bus stops with flashing red lights and an extended stop arm, all traffic in both directions must stop on undivided roads.
• On a highway with separate roadways divided by a depressed or raised median, physical barrier, or other intervening space, a driver on the different roadway need not stop for the bus.
• A center turn lane does not count as a divider. On 4+ lane roads without a raised median or barrier, all directions must stop.
• You must remain stopped until the school bus visual signal lights are no longer being actuated.
• Colorado requires stopping at least 20 feet from the front or rear of a stopped school bus with flashing red lights. Violation can result in significant fines and points on your license.
• Railroad crossings: School buses must stop at ALL railroad crossings, with or without passengers, even if no lights are flashing and no train is visible. This is a frequently tested rule.

Emergency Vehicles

• When you see or hear an emergency vehicle (police, fire, ambulance) with lights or siren: pull to the right edge of the road and stop. Do not block intersections.
• Move Over Law (Colorado): Colorado law applies to any stationary vehicle on the roadside with hazard or safety lights flashing. On a highway, move over one lane when safe; if you cannot, slow to at least 20 mph below the posted speed. On other roads, slow to 25 mph or less when the limit is below 45 mph, or at least 20 mph below the limit when it is 45 mph or higher.

8. DUI & DWAI: Two Impairment Tiers

Colorado is one of the few states with two distinct impaired-driving offenses, DWAI starts at 0.05% BAC (impaired to the slightest degree) and DUI kicks in at 0.08% (substantially incapable of safe driving). Marijuana DUI is enforced on the same standard. Refusing a chemical test costs you a 1-year revocation plus a mandatory 2-year ignition interlock.

9. Seat Belts & Child Seats

What are Colorado car seat and booster seat laws in 2026? Colorado requires seat belts for the driver and all front-seat passengers, while children under 18 must be properly restrained under Colorado child passenger law. The child passenger protection law sets specific restraint requirements by age and weight; if a parent is not in the vehicle, the driver is responsible for ensuring the child is properly restrained.

Children under 2 who weigh 40 pounds or more must use a rear-facing or forward-facing child restraint. Children ages 2 to under 4 who weigh at least 20 pounds must use a rear-facing or forward-facing child restraint, in the rear seat if one is available.

10. Where You Cannot Park

Colorados parking rules include specific distance limits: 15 feet from a fire hydrant, 20 feet from an intersection crosswalk, 30 feet on the approach to a stop sign, yield sign, flashing beacon, or traffic signal, and 50 feet from the nearest rail of a railroad crossing. Bike lanes are also off-limits. Know every prohibition for the Colorado DMV test:

• Within 15 feet of a fire hydrant
• Within 20 feet of a crosswalk at an intersection
• Within 30 feet of a stop sign, yield sign, or traffic signal
• Within 50 feet of a railroad crossing
• On a sidewalk, in front of a driveway, or on a bridge
• In a no-parking zone or alongside a curb painted yellow or red
• Double parking (alongside a vehicle already parked at the curb)
• In a designated bicycle lane, except when necessary to avoid conflict with other traffic or when directed by police or an official traffic control device
• Headed downhill: turn wheels toward the curb. Headed uphill with a curb: turn wheels away from curb. Uphill without a curb: turn wheels toward the shoulder.

11. Driving in Bad Weather

Colorados weather is legendary for its unpredictability, blue skies can turn into a whiteout blizzard on a mountain pass within minutes. Black ice forms on shaded canyon roads even when it is sunny nearby. Heres what the Colorado Driver Handbook says about handling it:

• Headlights required from sunset to sunrise or whenever visibility is less than 1,000 feet. In fog, use low beams, high beams reflect off fog and cut visibility further.
• Colorado I-70 traction law: From Sept. 1 through May 31, the Passenger Vehicle Traction Law is in effect on the I-70 Mountain Corridor between Dotsero and Morrison. CDOT may also activate traction or chain laws on other state highways when conditions require. When a Traction Law is active, motorists must meet the posted tire, tread-depth, chain, or approved traction-device requirements.
• In heavy fog, use low beams, high beams reflect off fog and reduce visibility.
• If you start to hydroplane, ease off the gas gently. Do not brake hard or turn sharply.
• In icy conditions, brake gently well in advance. Start slowing earlier than normal. Leave extra following distance.
• If your car goes into a skid, steer in the direction you want the front of the car to go. Do not overcorrect.
• Never use cruise control on wet, icy, or slippery roads.

12. Points & License Suspensions

Colorado tracks moving violations through its point system. Accumulating enough points can trigger a suspension hearing. DUI carries 12 points and DWAI carries 8 points. Heres how Colorados point system works:

Note: Colorados DMV can also require re-examination if your driving record shows a pattern of violations. Losing your license in Colorados mountain communities, where driving is often the only transport option, is a serious consequence.

2026 speeding-point rule: Effective August 12, 2026, qualifying repeat speeding violations add 2 points for a second violation in 12 months, 4 points for three or more violations in 24 months, and 8 points for five or more violations in five years. Driving at 100 mph or more adds 4 additional points.

13. Headlight Rules

Colorados wide-open rural highways and mountain roads demand good headlight discipline. The law specifies exactly when to switch to low beams, 500 feet oncoming, 200 feet following. That following distance difference from other states is a common test error.

Key test point: Colorados rule is 500 feet for oncoming and 200 feet for following, not 300. This distinction from other states is a frequent source of wrong answers on the Colorado DMV knowledge test.

14. Night Driving

Driving at night in Colorado is a different challenge than in most states. Mountain passes, unlit canyon roads, and elk crossing highways at dusk create hazards that flat-state drivers never face. The Colorado handbook calls out dawn and dusk specifically as more hazardous than daytime driving.

15. Cell Phones & Distracted Driving

Colorado enacted a statewide ban on handheld mobile device use while driving. Any use of a handheld device, calls, texting, scrolling, is prohibited. Can you use a phone at a red light in Colorado? No. The hands-free law still applies while stopped in traffic or at a stoplight.

Key test point: Colorados handheld ban applies to all drivers, not just texting, and it also applies while stopped in traffic or at a red light. On mountain roads, distracted driving is not just illegal, it is lethal.

16. Railroad Crossings

Colorados rail lines cross highways throughout the Front Range and mountain corridors. The knowledge test expects you to know exactly how far back to stop and which vehicles must always stop at crossings, regardless of signals.

Key test point: Never drive around or under a lowered crossing gate, it is illegal and extremely dangerous. Wait until gates are fully raised and all tracks are clear.

17. How to Drive a Roundabout

Roundabouts are common at Colorado intersections from Denver suburbs to mountain resort towns like Breckenridge and Vail. The Colorado DMV tests them directly. The rule that trips everyone up: you always yield when entering, regardless of what the driver inside is doing.

Key test point: The most common wrong answer on roundabout questions is thinking you have right-of-way when entering. You never do, yield to traffic already inside.