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

What is the default speed limit in Illinois when no sign is posted in a residential area? Illinois sets 30 mph in urban areas by law. The Illinois knowledge test is 35 questions with 80% required. DUI threshold: 0.08% for adults, 0.00% for under-21 (zero tolerance). Illinois has a strict phone law: handheld use is banned for all drivers, primary offense. Headlights are required from sunset to sunrise and when rain, snow, fog, or other atmospheric conditions require windshield wipers.

1. Speed Limits in Illinois

Illinois sets statutory speed limits by road classification, and local municipalities can post different limits where warranted. Speeding is identified in Illinois handbook as one of the leading causes of crashes, deaths, and serious injuries. Heres the full statutory breakdown that applies unless otherwise posted:

Key test point: Illinois law says you may drive at the maximum allowable speed only under safe conditions. Local municipalities may post limits lower than the state statutory defaults. In construction or maintenance speed zones, the posted limit applies whether workers are present or not; the minimum speeding fine is $250 for a first violation and $750 for a second or subsequent violation. You must also slow down at intersections, curves, hilltops, and on narrow or winding roads, even if you are under the posted limit.

2. Right-of-Way: Who Goes First

Illinois right-of-way rules are tested extensively on the knowledge exam. One rule specific to Illinois: funeral processions have the right-of-way, you may not cut through one, and all vehicles in a procession should use headlights and hazard flashers. Right-of-way is always yielded, never taken.

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: 100 vs 200-Foot Signal Rule

Illinois has a two-tier signal distance rule: 100 feet in business or residential areas, 200 feet in all other areas. The handbook also covers the Dutch Reach, opening your car door with your far hand to force you to look for cyclists. Right turns on red are generally permitted after a full stop:

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 where not prohibited by a sign; must not interfere with traffic. Illegal in Illinois on curves and hills unless there is a clear view for at least 500 feet in each direction, and wherever signs prohibit U-turns.

4. Lane Rules & Tollway Laws

Illinois has over 2,400 miles of tollway and interstate where lane discipline is especially critical. The Illinois Tollway bans hauling house trailers in high winds. On any multi-lane road, knowing which lines you can and cannot cross is tested every time on the Secretary of State exam:

Center turn lane (CTSL)

Used only to prepare for or make a left turn from or into the roadway, or for a permitted U-turn; not for through travel or passing.

Solid white line

Crossing a single solid white line requires special care and is discouraged. Double solid white lines may not be crossed.

Solid yellow line (your side)

No passing. You may cross for a permitted left turn into or from an alley, private road, driveway, or street.

Broken yellow line

Passing allowed when safe.

Solid + Broken yellow centerline

Passing allowed only on the broken-line side.

Illinois left-lane law: On interstates and full-access controlled freeways, use the left lane for passing except when an allowed condition such as congestion, weather, a hazard, or yielding to emergency or construction vehicles makes left-lane use necessary. Illinois zipper merge rule: When traffic is not congested, merge into the open lane early. During congestion, use both lanes to the lane-reduction point and alternate vehicles at the merge.

5. Passing Another Vehicle

Illinois requires a driver using the oncoming lane to return to the proper lane before getting within 200 feet of an oncoming vehicle. Heres the full breakdown:

• Only pass on the left, using the oncoming lane, when it is safe and legal.
• Do not pass within 100 feet of an intersection or railroad crossing, or where a hill, curve, bridge, viaduct, or tunnel blocks the required view. All Illinois construction zones are no-passing zones. Look for the No Passing Zone pennant sign.
• The vehicle being passed must not speed up while you are overtaking.
• Return to your lane before getting within 200 feet of any oncoming vehicle.
• When passing a bicyclist or a pedestrian traveling on the roadway or shoulder, leave at least 3 feet of clearance.
• Never pass a stopped school bus with flashing red lights when Illinois law requires you to stop; opposite-direction traffic on a four-lane roadway is not required to stop.
• You may pass on the right only where Illinois law permits, including when the vehicle ahead is turning left and there is enough room, on a one-way roadway or a roadway with two or more clear lanes in each direction, or at an intersection widened for that purpose. Do not pass on the shoulder.

6. Following Distance

Use the Illinois 3-second following distance rule on good roads and in good weather. When road or weather conditions are not good, increase the following distance beyond 3 seconds.

7. School Buses & Funeral Processions

Illinois tests school bus rules, the Move Over law, and funeral procession rules on every knowledge exam. In Illinois, cutting through a funeral procession is illegal, and all vehicles in a procession must display headlights and hazard flashers.

School Buses

• When a school bus stops to load or unload passengers with flashing red lights and an extended stop arm, drivers meeting or overtaking the bus must stop unless an Illinois exception applies.
• On a four-lane roadway, a driver traveling in the opposite direction from a stopped school bus is not required to stop.
• On two-lane roads and in other situations covered by Illinois law, traffic meeting or overtaking a school bus that is stopped to load or unload passengers must stop.
• You must remain stopped until the stop arm is retracted and the flashing lights are turned off, or the school bus driver signals you to pass.
• A conviction for illegally passing a stopped school bus carries a mandatory $300 fine, community service set by the court, and a driver's license suspension.
• Railroad crossings: School buses are among the vehicles required by Illinois law to stop at most railroad crossings.

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.
• Scott's Law / Move Over Law (Illinois): When approaching a stationary emergency vehicle, tow truck, highway maintenance vehicle, or any vehicle with hazard lights on a road with two or more lanes in the same direction, move to a lane not immediately adjacent to the vehicle. If a lane change is not possible, reduce speed. Illinois also prohibits using wireless devices within 500 feet of an emergency scene.

8. DUI Laws: Violent Crime Status

DUI in Illinois is not just a traffic offense, it is classified as a violent crime and stays on your driving record permanently. Illinois also has specific cannabis DUI rules: a THC level of 5 nanograms/mL in whole blood is illegal, and cannabis must be transported in a sealed, odor-proof, child-resistant container. Zero tolerance for drivers under 21 means any detectable alcohol, greater than 0.00%, triggers suspension.

9. Seat Belts & Child Seats

Illinois requires all drivers and passengers age 8 and older to wear safety belts, front and rear, even in vehicles with air bags. Under age 8 is governed by the Child Passenger Protection Act. The driver is responsible for ensuring ALL passengers comply.

10. Where You Cannot Park

Illinois divides parking prohibitions into three tiers: places where you cannot stop, places where you cannot stand, and places where you cannot park. The Secretary of State exam tests all three. Local municipalities may add restrictions beyond these statewide rules, always check posted signs:

• 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)
• 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

Illinois weather can be brutal, lake-effect snow off Lake Michigan, fog-dense river bottom roads along the Illinois and Mississippi, and spring flooding that swamps I-55 underpasses. The Illinois Tollway specifically bans hauling house trailers in high winds. Heres what the Rules of the Road handbook says:

• Headlights required in Illinois when rain, snow, fog, or other atmospheric conditions require windshield wipers. They are also required from sunset to sunrise and should be used when objects 1,000 feet away cannot be seen.
• 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

Illinois uses a point system and separate repeat-offense rules. Drivers age 21 and older with three or more point-assigned traffic offenses committed within 12 months may be reviewed for suspension or revocation. Drivers under 21 convicted of two or more moving violations within 24 months face a minimum 30-day suspension. DUI convictions trigger revocation on a separate schedule. Heres how the consequences break down:

Note: Illinois assigns points to moving violations. The point total, prior driving record, and applicable repeat-offense rule are used to determine whether driving privileges are suspended or revoked and for how long.

13. Headlight Rules

Illinois codifies two headlight rules that frequently appear on the Secretary of State exam: headlights are required when rain, snow, fog, or other atmospheric conditions require windshield wipers, and bright lights must be dimmed at exactly 500 feet before meeting oncoming traffic or 300 feet before passing a vehicle.

Key test point: Oncoming = dim at 500 feet. Passing = dim at 300 feet. Note the difference from some other states: Illinois uses "passing a vehicle" (300 feet) rather than "following a vehicle." Also: when atmospheric conditions require windshield wipers, headlights are required; headlights should also be used when objects 1,000 feet away cannot be seen.

14. Night Driving

Illinois handbook flags rural intersections at night as a specific hazard, some are marked with warning signs, others have nothing. The Rules of the Road advises slowing down and looking both ways at every rural intersection at night, regardless of signs. Glare from oncoming headlights is a recurring concern in Illinois flat terrain where lights are visible for great distances.

15. Cell Phones & Distracted Driving

Illinois has a statewide hands-free law: handheld electronic communication device use while operating a motor vehicle is prohibited. Drivers age 19 and older may use hands-free or voice-operated devices; drivers under 19 generally may not use a cellphone even hands-free except to contact specified emergency services.

Key test point: Handheld electronic communication device use is prohibited while operating a motor vehicle. Drivers age 19 and older may use hands-free functions. Illinois also prohibits wireless device use and photography within 500 feet of an emergency scene, subject to specified exceptions.

16. Railroad Crossings

Illinois has one of the most extensive rail networks in the nation, Chicago is the national freight rail hub, and rail crossings appear across every county. The Illinois Secretary of State exam tests the exact stop distance range 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 increasingly common at Illinois intersections, particularly in the Chicago suburbs, Springfield, and along state route improvements. The Secretary of State tests them directly. The one rule that trips everyone up: entering traffic must always yield to vehicles already circulating inside the roundabout.

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.