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 30 minutes after sunset and during adverse weather.

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. On construction zones, fines are doubled and violations can result in suspension. 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 begin or complete a left turn; not for through travel or merging. You may travel no more than 300 feet in the CTSL.

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

Illinois handbook includes a truck-specific passing rule: blink your headlights when passing a truck to let the driver know it is safe to move back over. And you must return to your lane before getting within 200 feet of any 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, 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.
• Return to your lane before getting within 200 feet of any oncoming vehicle. Blink your headlights to signal to a truck driver that it is safe to move back over after you pass.
• 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

Illinois dense urban traffic on I-90, I-290, and the Tri-State Tollway means rear-end crashes are a constant risk. The 3-second rule is your minimum baseline on Illinois roads, and in Chicago stop-and-go conditions, maintaining it takes active effort.

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 with flashing red lights and an extended stop arm, all traffic in both directions must stop on undivided roads.
• On roads with a true median or physical barrier, only traffic behind the bus must stop, oncoming traffic may proceed.
• 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 red lights stop flashing and the stop arm is retracted.
• Illinois penalty for illegally passing a stopped school bus: significant fines, points on your record, and possible suspension. You must stop as long as the red lights are flashing and the stop arm is extended, remain stopped until all children are safely across the road.
• 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 (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 whenever operating windshield wipers, it is the law. Also required from sunset to sunrise and 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 suspends your license for three moving violations in a 12-month period, and DUI convictions trigger revocation on a separate, escalating schedule. The Secretary of States office tracks all convictions permanently. Heres how the consequences break down:

Note: Illinois does not use a simple point counter, the three-violation-in-12-months rule triggers suspension. A Probationary License (for drivers 21+) or Occupational Driving Permit may be available during suspension periods with a completed driver improvement course.

13. Headlight Rules

Illinois codifies two headlight rules that frequently appear on the Secretary of State exam: headlights are required whenever windshield wipers are in use, 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: wipers on = headlights on, and headlights are needed when objects 1,000 feet away cannot be seen, both tested on the Illinois exam.

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 complete hands-free law, handheld phone use while driving is prohibited for all drivers. And Illinois goes further: a driver who causes a crash through distracted driving may face criminal penalties and incarceration. In work zones, wireless device fines are doubled.

Key test point: Illinois hands-free law applies to all drivers, no handheld devices while moving. Work zone violations are doubled. And critically: if you cause a crash by driving distracted in Illinois, you face criminal penalties and possible incarceration, not just a fine. Cell phone use is also banned within 500 feet of an emergency scene.

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.