Illinois speed limits and key traffic laws
Illinois sets default speed limits for each type of road, with extra rules for school zones, construction zones and emergency scenes. Local towns can post different limits, so the sign you see always comes first.
This page also covers some of the laws Illinois learners are most often tested on: passing a stopped school bus, Scott's Law and keeping out of the left lane on interstates.
By the end of this topic you can
- You can state the default Illinois speed limits for each road type.
- You can explain when the 20 mph school zone limit applies.
- You can describe what Illinois law requires in a construction zone.
- You can explain when you must stop for a school bus.
- You can describe what Scott's Law requires near emergency vehicles.
What you need to know and understand
- Unless posted otherwise: interstates and tollways 70 mph, four-lane highways 65 mph, other highways and rural areas 55 mph, city and town areas 30 mph, alleys 15 mph.
- School zone limit is 20 mph on school days between 6:30 a.m. and 4 p.m. when children are present and signs are posted.
- Construction zone speed limits apply 24 hours a day, seven days a week, whether or not workers are there.
- All construction zones in Illinois are no passing zones.
- Passing a stopped school bus with its stop arm out brings a license suspension and a mandatory $300 fine.
- Under Scott's Law, from January 1, 2026 drivers must also yield to emergency vehicles showing flashing lights whether stationary or moving.
- On interstates and full access controlled freeways, the left lane is for passing only, with limited exceptions.
Default limits and driving for conditions
The maximum speed is only allowed when conditions are safe. You must slow down approaching and crossing intersections, on curves, near the top of a hill and on narrow winding roads. Where a minimum speed is posted, driving slower is illegal unless needed for safety, and where none is posted you should not drive so slowly that you hold up normal traffic.
In school zones you must also stop using your phone, unless hands-free, and stop for anyone in the crosswalk. Remember that drivers under 19 may not use a phone at all.
Work zones and Scott's Law
In a construction or maintenance zone you must slow down, stop using a handheld phone, yield to workers and authorized vehicles, change to a lane away from workers when you can, and keep your speed down until you are past them.
Scott's Law applies when you approach a stopped emergency or maintenance vehicle with flashing lights, or an emergency scene. Change lanes away if you safely can; if not, slow down and pass with caution. The Illinois State Police say that from January 1, 2026 the duty to yield also covers moving emergency vehicles showing flashing lights, plus workers and pedestrians at the scene. Fines start at $250 for a first violation and can reach $10,000, and photography or phone use within 500 feet of an emergency scene is banned with limited exceptions. Our deeper Scott's Law guide covers the penalties in full.
School buses and passing rules
You must stop for a school bus that is loading or unloading with its stop arm out, from either direction. The only exception is on a four-lane road when the bus is on the opposite side. The bus warns you with flashing lights at least 100 feet before stopping, or 200 feet in rural areas. Stay stopped until the arm is folded and the lights stop, or the driver waves you on.
- No passing within 100 feet of an intersection or railroad crossing on a two-lane road.
- No passing in a school zone or construction zone.
- Return to your lane before you get within 200 feet of an oncoming vehicle.
- Leave at least 3 feet when passing a pedestrian or a bicyclist.
Common mistakes
- Speeding up in a work zone because no workers are visible. The posted work zone limit applies at all times.
- Driving past a stopped school bus on a two-lane road because you are traveling the other way. You must stop.
- Sitting in the left lane of an interstate. Move right unless you are passing or an exception applies.
- Assuming 30 mph applies everywhere in town. Alleys are 15 mph and school zones 20 mph when the conditions are met.
Test yourself: Illinois speed limits and key traffic laws
Answer each question, then read the explanation. Questions come in a random order each time.
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Sources: Illinois Rules of the Road 2026, Chapter 4: Traffic Laws (Illinois Secretary of State); Move Over Law (Scott's Law) information page (Illinois State Police). Independent guide, not affiliated with any licensing agency. Always check the latest official rules with the Illinois licensing agency.