This comprehensive guide to Montana traffic laws provides clear, actionable explanations of the most commonly searched driving rules in Big Sky Country. Whether you're navigating I-90 from Billings to Missoula, I-15 through Great Falls and Butte, scenic highways through Glacier and Yellowstone National Parks, or rural Montana backroads with abundant wildlife, understanding Montana-specific traffic regulations helps you stay safe and avoid costly violations. From double yellow line rules to school bus stop requirements, wildlife safety, reasonable and prudent speed laws, right turn on red, seatbelt requirements, and DUI regulations—every section references the official Montana Code Annotated (MCA) and guidance from Montana Department of Justice Motor Vehicle Division (MVD) and Montana Department of Transportation (MDT). This is educational information, not legal advice; always obey posted signs, signals, and directions from law enforcement.
Montana highways including I-90, I-15, I-94, and scenic mountain roads require strict adherence to lane markings and wildlife safety.
In Montana, double solid yellow centerlines mark a no-passing zone where vehicles traveling in either direction are prohibited from crossing into the opposing lane to overtake another vehicle. According to MCA §61-8-329, these markings appear on mountain passes, curves, hills, narrow bridges, and areas where sight distance is limited. Violating this law can result in fines ranging from $85 to $200, plus 3 points on your Montana driving record and potential insurance premium increases. Montana Highway Patrol actively enforces no-passing zones on I-90, I-15, I-94, US-93, US-2, Beartooth Highway (US-212), and rural county roads throughout Big Sky Country.
Legal Exceptions: When You May Cross Double Yellow Lines in Montana
Montana law recognizes several limited exceptions where drivers may legally cross double solid yellow lines:
Left turns into driveways and private roads: You may cross double yellow lines when making a left turn into a residential driveway, ranch entrance, business access, forest service road, or private property, provided it is safe and no oncoming traffic is present.
Legal U-turns where permitted: Montana allows U-turns across double yellow lines where U-turns are not specifically prohibited by signs, ordinances, or due to limited visibility. U-turns are prohibited in business districts, on curves, near hilltops, and where you cannot be seen by approaching drivers within 500 feet.
Avoiding obstructions in your lane: When a temporary obstruction blocks your lane—such as a disabled vehicle, fallen debris, road maintenance equipment, wildlife carcass, or accident scene—you may briefly cross the centerline if the opposing lane is clear and the maneuver can be done safely.
Following official directions: When law enforcement officers, Montana Highway Patrol, traffic control personnel, emergency responders, or construction flaggers direct you to cross the centerline, you must follow their instructions.
These exceptions do not permit passing slow-moving vehicles, agricultural equipment, recreational vehicles, or general traffic. The maneuver must be necessary, brief, and safe for all road users.
Montana I-90 Corridor: Double Yellow Line Enforcement Across the State
Interstate 90 (I-90) crosses Montana for 554 miles from the Idaho border near Lookout Pass to the Wyoming border near Wyola, serving as the primary east-west corridor through Missoula, Butte, Bozeman, Livingston, and Billings. While I-90 uses white lane markings on the main interstate, double yellow lines appear on entrance/exit ramps, service roads, frontage roads, and connector routes. Montana Highway Patrol maintains consistent enforcement along the entire I-90 corridor, with particular attention to construction zones, mountain passes including Homestake Pass and Bozeman Pass, and high-traffic areas near cities.
Montana's most spectacular scenic highways—Going-to-the-Sun Road through Glacier National Park and Beartooth Highway (US-212) near Yellowstone—feature extensive double yellow no-passing zones due to steep grades, hairpin curves, narrow shoulders, and dramatic elevation changes. These roads require absolute adherence to lane markings. Montana law strictly prohibits passing across double yellow lines on mountain roads—wait for designated turnouts or pullouts to allow faster traffic to pass. During summer tourist season (June-September), Montana Highway Patrol increases enforcement on popular scenic routes.
Montana law prohibits passing across double yellow lines but allows left turns into driveways and ranch roads when safe.
Montana Right Turn on Red & Traffic Signal Laws
Montana Statute MCA §61-8-402: Right on Red After Complete Stop
Montana law permits right turns on red signals after coming to a complete stop at the stop line, crosswalk, or intersection edge, unless a "NO TURN ON RED" sign prohibits it. Before turning, drivers must:
Come to a full stop—your vehicle must reach zero miles per hour
Yield to pedestrians in or approaching the crosswalk
Yield to all vehicles and cyclists with the right-of-way
Check for "NO TURN ON RED" signs, which may apply at all times or during specific hours
Ensure the turn can be made safely without interfering with traffic flow
Rolling through the stop or blocking the crosswalk is a common violation. Montana courts treat incomplete stops seriously, with fines typically ranging from $85 to $150 plus court costs and 3 points on your license.
Billings, Missoula & Bozeman: Urban No Turn on Red Zones
Montana's larger cities including Billings (downtown and near MetraPark), Missoula (near University of Montana campus and downtown), Bozeman (Main Street and near Montana State University), Great Falls (downtown district), and Helena (near State Capitol) post "NO TURN ON RED" signs at busy pedestrian intersections and complex signal sequences. Always read supplemental plaques—some restrictions apply only during specific hours, school zones, or when pedestrians are present.
Left Turn on Red in Montana: One-Way to One-Way Streets
Montana permits left turns on red from one-way streets onto other one-way streets, provided you come to a complete stop, yield to pedestrians and traffic, and no sign prohibits the turn. This scenario occurs primarily in downtown Billings, Missoula, Great Falls, Butte's historic uptown district, and Helena near the capitol complex. Before attempting a left turn on red, verify that both streets are one-way in the appropriate directions and check for prohibitive signage.
Montana Traffic Signal Timing & Yellow Light Duration
Montana traffic signals follow Montana Department of Transportation (MDT) and Federal Highway Administration (FHWA) guidelines for yellow (amber) light timing, typically 3-5 seconds depending on intersection speed limits and approach geometry. If you are already in the intersection when the light turns red, complete your movement safely. Entering on yellow is legal if you cannot stop safely; entering on red is a violation subject to citation. Montana does not currently use automated red light cameras statewide, but enforcement by Montana Highway Patrol and local officers remains active at high-violation intersections.
School Zone Traffic Signals: Flashing Yellow Lights in Montana
Montana school zones use flashing yellow beacons to indicate reduced speed limits when children are present, typically 15-20 mph during school hours (usually 7:30-9 AM and 2:30-4 PM on school days). Some school zones use advanced warning systems with speed feedback displays. Always observe posted school zone speed limits— violations in school zones carry doubled fines up to $200 and 3 points on your license. Montana takes school zone safety seriously in both urban and rural communities.
Montana has numerous railroad grade crossings, particularly along BNSF Railway and Montana Rail Link routes serving Billings, Great Falls, Missoula, and smaller communities. When crossing signals activate (flashing red lights and/or gates descending), you must stop at least 15 feet from the nearest rail. Never drive around lowered gates or attempt to beat a train—Montana law (MCA §61-8-370) imposes severe penalties including fines up to $500, 3 points, possible license suspension, and criminal charges if violations result in accidents or injuries. Montana coal, grain, and freight trains can exceed 100 cars, requiring several minutes to clear crossings.
In Montana, always stop fully and yield to pedestrians before making a right turn on red.
Montana School Bus Stop Laws & Penalties
Montana Statute MCA §61-7-109: Stopping for School Buses
Montana enforces strict school bus stop laws to protect children. When a school bus activates flashing red lights and extends its stop arm, the following rules apply under MCA §61-7-109:
Undivided roads (no median): All vehicles traveling in both directions must stop at least 30 feet from the bus and remain stopped until the red lights stop flashing and the stop arm retracts.
Divided highways (physical median or barrier): Only traffic traveling in the same direction as the bus must stop. Opposing traffic on the other side of a physical divider may proceed cautiously.
Multi-lane roads without median: All lanes in both directions must stop. Painted center turn lanes or double yellow lines do not count as physical dividers.
Passing a stopped school bus is a serious violation in Montana. First-offense penalties include fines of$100 to $300, 3 points on your driving record, and possible driver improvement course requirements. Repeat offenses or violations causing injury carry substantially higher penalties including license suspension and criminal charges.
Montana School Bus Camera Programs: Stop-Arm Video Enforcement
Many Montana school districts equip buses with exterior stop-arm cameras that record license plates of vehicles illegally passing stopped buses. Video footage is reviewed by school resource officers and Montana Highway Patrol, who issue citations to registered owners. Camera-based enforcement is expanding throughout Montana's urban and rural school districts. Expect strict enforcement during morning (7-9 AM) and afternoon (2:30-4 PM) school hours on all roads including highways, rural routes, and residential streets.
Flashing Yellow vs Flashing Red School Bus Signals
Montana school buses first activate flashing yellow lights approximately 300 feet before the intended stop to warn drivers that the bus is preparing to stop for children. You should slow down and prepare to stop but are not yet legally required to do so. Once the flashing red lights activate and the stop arm extends, you must come to a complete stop. Do not proceed until the red lights stop flashing, the stop arm retracts, and all children are clear of the roadway.
Rural Montana School Bus Safety: Open Roads and Long Distances
Montana's rural character means school buses often travel long distances on open highways and county roads with 65-70 mph speed limits. When you see a school bus ahead, begin slowing early—buses may stop frequently for rural students. Montana law requires full stops for school buses even on high-speed rural highways unless a physical median separates traffic. Children's safety depends on complete compliance with school bus stop laws across Montana's vast distances.
On undivided Montana roads, all traffic in both directions must stop when a school bus displays flashing red lights.
Montana is home to abundant wildlife including white-tailed deer, mule deer, elk, moose, pronghorn antelope, bighorn sheep, black bears, and grizzly bears. Wildlife-vehicle collisions are a leading cause of accidents and injuries in Montana, with thousands of incidents reported annually. Montana law requires drivers to exercise reasonable care to avoid collisions with wildlife, particularly in posted wildlife crossing zones marked with yellow diamond warning signs.
Montana's most dangerous wildlife corridors include I-90 near Missoula (Evaro Hill), US-93 from Missoula to Kalispell (recognized as one of North America's deadliest wildlife highways), Highway 200 across central Montana, I-15 near Helena and Great Falls, and highways near Glacier and Yellowstone National Parks. Montana Department of Transportation has installed wildlife underpasses, overpasses, and fencing in critical areas, but collisions remain frequent.
Reducing Wildlife Collision Risk: Speed, Awareness & Night Driving
To reduce wildlife collision risk in Montana:
Reduce speed at dawn and dusk: Wildlife is most active during twilight hours (5-8 AM and 6-10 PM) when visibility is reduced.
Scan roadsides continuously: Watch for eye reflections, movement in brush, and animals on road shoulders.
Expect multiple animals: Deer and elk often travel in groups—if you see one, expect more to follow.
Don't swerve for smaller animals: Maintain control and brake firmly in a straight line. Swerving can cause rollover crashes or head-on collisions, which are far more dangerous than hitting a deer.
Use high beams when possible: High beams illuminate more roadside area and make wildlife eye reflections visible sooner.
Obey wildlife warning signs: Yellow diamond signs mark proven high-collision areas—reduce speed and increase alertness.
Montana Wildlife Collision Reporting Requirements
Montana law requires reporting wildlife collisions involving injury, death, or property damage exceeding $1,000 to Montana Highway Patrol or local law enforcement. If you strike and kill a deer, elk, moose, or antelope, you must report it to Montana Fish, Wildlife & Parks (FWP) within 24 hours. Montana has a salvage permit system allowing people to legally claim roadkill wildlife for meat—contact FWP for permit information. Never leave an accident scene involving wildlife without reporting it, as abandoned carcasses create additional hazards for other drivers.
Montana Speed Limit Laws: Reasonable and Prudent Speed
Montana Statute MCA §61-8-303: Maximum Speed Limits Statewide
Montana establishes maximum speed limits for different types of roads under MCA §61-8-303. Statutory speed limits include:
Gravel or dirt roads: 65 mph unless otherwise posted
Urban districts: 25 mph unless otherwise posted
School zones: 15-20 mph when children are present (flashing beacons active)
Always obey posted signs, which supersede statutory limits. Montana's daytime/nighttime split reflects safety concerns about reduced visibility, wildlife activity, and driver fatigue during darkness.
Montana Basic Speed Law: Reasonable and Prudent for Conditions
Montana enforces a basic speed law requiring drivers to operate at speeds reasonable and prudent for current road, traffic, and weather conditions (MCA §61-8-303). This means you can be cited for driving too fast for conditions even if you're under the posted speed limit. Critical factors include:
Weather conditions: Snow, ice, rain, fog, wind, or reduced visibility
Road surface: Gravel, mud, snow-packed, icy, or under construction
Traffic density: Heavy traffic, congestion, or slow-moving vehicles
Wildlife presence: Known wildlife crossing areas require reduced speed
Curves and grades: Mountain passes, steep descents, sharp curves
Montana experiences severe winter weather including blizzards, ice storms, ground blizzards (near-zero visibility from blowing snow on open plains), and rapid temperature changes. Reduce speed appropriately for conditions—failure to do so can result in citations for "driving too fast for conditions" (MCA §61-8-303) plus liability for any resulting accidents.
Montana Point System & License Suspension Thresholds
Montana uses a point system administered by the Montana Motor Vehicle Division (MVD). Common speeding violations add:
1-10 mph over limit: 2 points
11-20 mph over limit: 3 points
21-30 mph over limit: 4 points
31+ mph over limit: 5 points (may also result in reckless driving charges)
Accumulating 30 or more points within 36 months triggers license suspension. Montana offers defensive driving courses to reduce points for eligible violations, subject to court approval. Serious violations including reckless driving, DUI, or fleeing police result in immediate license suspension regardless of point totals.
Work Zone Speed Limits & Doubled Fines in Montana
Montana law authorizes doubled fines for speeding and other moving violations in active highway work zones when workers are present (MCA §61-8-715). Work zones are marked by orange construction signs, cones, barrels, and reduced speed limits (typically 45-65 mph depending on conditions). Montana posts "SPEED FINES DOUBLE WHEN WORKERS PRESENT" signs to warn drivers. A typical $85 speeding ticket can double to $170 in an active work zone, plus court costs and points. Montana Highway Patrol and MDT take work zone safety extremely seriously due to multiple worker fatalities in recent years.
Montana defines reckless driving (MCA §61-8-301) as operating a vehicle with willful or wanton disregard for the safety of persons or property. Reckless driving is a misdemeanor carrying fines up to $300, up to 90 days in jail, license suspension, and 5 points. Behaviors that may constitute reckless driving include excessive speed (30+ mph over limit), racing, intentional lane violations, or aggressive maneuvers endangering others. Montana also recognizes careless driving (MCA §61-8-301.5) as a lesser offense for driving without due caution, carrying fines and points.
Speed Enforcement Methods: Radar, LIDAR & Aircraft Patrol in Montana
Montana Highway Patrol uses radar, LIDAR (laser), pacing, and occasional aircraft speed enforcement on interstates and major highways. Radar detectors are legal in Montana for passenger vehicles but do not exempt you from speed limits. Some interstate corridors including I-90, I-15, and I-94 use aircraft speed enforcement—watch for pavement markings (painted white lines at measured intervals) and "SPEED ENFORCED BY AIRCRAFT" signs. Contesting speeding tickets requires appearing in the issuing justice court or municipal court; consult a traffic attorney for serious violations or commercial driver license (CDL) holders facing violations.
Montana DUI Laws & Alcohol-Related Driving Offenses
Montana Statute MCA §61-8-401: Driving Under the Influence
Montana prohibits operating a motor vehicle with a blood alcohol concentration (BAC) of 0.08% or higher for drivers 21 and over, 0.02% or higher for drivers under 21 (zero tolerance), and 0.04% or higher for commercial drivers (MCA §61-8-401, §61-8-465). Even if your BAC is below the legal limit, you can still be charged with DUI if alcohol, marijuana, or drugs have impaired your ability to drive safely. Montana courts take DUI offenses extremely seriously.
Fines: $600-$1,200 plus court costs, fees, and surcharges
License suspension: 6 months minimum
Alcohol evaluation and treatment: Mandatory assessment and completion of recommended treatment program
Ignition interlock possible: May be required for license reinstatement
Community service: Possible requirement depending on county
Penalties increase substantially for repeat offenses, high BAC levels (0.16% or above considered "aggravated"), refusal to submit to chemical testing, or DUI incidents involving accidents, injuries, minors in the vehicle, or occurring in a commercial vehicle.
Montana Implied Consent Law & Chemical Test Refusal
Under Montana implied consent law (MCA §61-8-402), by driving on Montana roads you automatically consent to chemical testing (breath, blood, or urine) if lawfully arrested for DUI. Refusing the test results in automatic administrative penalties:
First refusal: 6-month license suspension
Second refusal within 5 years: 1-year suspension
Third or subsequent refusal: 1-year suspension plus enhanced criminal penalties
Refusal does not prevent prosecution—the state can still charge you with DUI based on officer observations, field sobriety tests, and other evidence. Refusal can be used against you in court and typically results in harsher penalties if convicted. Montana law enforcement strongly encourages drivers to submit to testing, and refusal is treated as evidence of consciousness of guilt.
24/7 Sobriety Program & Ignition Interlock in Montana
Montana operates a 24/7 Sobriety Program allowing certain DUI offenders to avoid jail time by submitting to twice-daily breath testing at a law enforcement facility. Participants must appear at designated times morning and evening to blow into a breath-testing device. Any positive test results in immediate sanctions. Additionally, Montana requires ignition interlock devices (IID) for many DUI offenders seeking license reinstatement. An IID is a breath-testing device connected to your vehicle's ignition system. The engine will not start unless you provide a breath sample below the programmed limit (typically 0.02% BAC). You must use a state-approved IID provider and pay all installation, monthly monitoring ($70-$150/month), and removal costs. Attempting to circumvent the device, tampering, or having someone else blow into it is a criminal offense that can result in additional jail time, extended IID requirement, and license revocation.
Montana Seatbelt Laws & Child Passenger Safety
Montana Statute MCA §61-9-417: Seatbelt Requirements for All Occupants
Montana requires all vehicle occupants to wear properly fastened seatbelts regardless of seating position.Front seat occupants (driver and passenger) must wear seatbelts at all times. Rear seat occupants ages 6 and older must also wear seatbelts or appropriate child restraints. Montana is a secondary enforcement state for adult seatbelt violations, meaning officers cannot stop you solely for a seatbelt violation—they must have another reason for the stop. However, child restraint violations are primary enforcement, allowing officers to stop vehicles when they observe unrestrained children.
Montana Child Passenger Safety Laws: Car Seats & Booster Requirements
Children under 6 years old AND under 60 pounds: Must be secured in a child safety restraint system (car seat or booster seat) appropriate for the child's age, weight, and height.
Children 6 years and older OR 60 pounds and heavier: May use standard seatbelts if they fit properly (lap belt across upper thighs, shoulder belt across chest).
Rear-facing car seats: Recommended for infants and toddlers according to manufacturer instructions and American Academy of Pediatrics guidelines (typically until age 2 or longer).
Booster seats: Required for children who have outgrown forward-facing car seats but are too small for seatbelts alone (typically ages 4-8).
Violations of child restraint laws carry fines up to $100. More importantly, proper child restraints reduce injury and death risk by up to 70% in crashes. Montana Highway Patrol and local police offer free car seat inspections and installation assistance at checkpoints throughout the year.
Pickup Truck Passenger Safety: Riding in Truck Beds
Montana law (MCA §61-9-420) generally prohibits passengers from riding in cargo areas of pickup trucks on public roads, with exceptions for agricultural work, parades, and other specified activities. Children under 6 may never ride in pickup truck beds under any circumstances. Violations can result in fines and points on your license. Even where legal, riding in truck beds is extremely dangerous—occupants can be ejected in crashes, sudden stops, or sharp turns.
Montana Motorcycle Helmet Laws & Eye Protection
Montana does not require motorcycle helmets for riders over 18 years of age, making it one of the few states without a universal helmet law. However, riders under 18 must wear DOT-approved helmets. All motorcycle riders and passengers must wear eye protection (goggles, face shield, or safety glasses) unless the motorcycle is equipped with a windscreen. Despite the lack of a helmet requirement for adults, Montana strongly encourages all riders to wear helmets—motorcycle fatalities are significantly higher among unhelmeted riders, and medical costs from head injuries can be catastrophic.
Official Montana Traffic Law Resources & MVD Information
This guide summarizes common Montana traffic rules based on the Montana Code Annotated (MCA) and guidance from the Montana Department of Justice Motor Vehicle Division and MDT. It is not legal advice. Always follow posted signs, signals, and instructions from law enforcement. Consult an attorney for specific legal questions or if you are facing traffic citations or criminal charges.
