Sample Speed Limits questions
With no other limit posted, what is the speed limit on Illinois interstates and tollways?
Show the answer
70 mph
Illinois sets 70 mph on these roads unless a sign says otherwise. Local authorities may post a different limit.
Source: Illinois Rules of the Road (2026), Chapter 4, Traffic Laws: Speed Limits (p. 24)
When must you obey a posted construction zone speed limit in Illinois?
At all times, even with no workers present Only when orange lights are flashing Only when workers are visible Only on weekdays during daylight Show the answer
At all times, even with no workers present
The posted limit applies day and night, every day of the week. It may drop further when workers are present.
Source: Illinois Rules of the Road (2026), Chapter 4, Traffic Laws: Construction Zones (p. 25)
With no other limit posted, what is the speed limit in Illinois city and town areas?
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30 mph
Illinois sets 30 mph in cities and towns unless a sign shows another limit.
Source: Illinois Rules of the Road (2026), Chapter 4, Traffic Laws: Speed Limits (p. 24)
During which hours does the Illinois handbook apply the 20 mph school zone limit on school days?
6 a.m. to 6 p.m. 7:30 a.m. to 3 p.m. 6:30 a.m. to 4 p.m. 8 a.m. to 5 p.m. Show the answer
6:30 a.m. to 4 p.m.
The handbook gives this as the usual window, with signs posted and children present, and notes that school hours may vary.
Source: Illinois Rules of the Road (2026), Chapter 4, Traffic Laws: Speed Limits (p. 24); School Zones (p. 25); Other Special Signs (p. 69)
According to the Illinois handbook, what happens to your stopping distance when you double your speed?
It becomes ten times as long It stays about the same It becomes four times as long It becomes twice as long Show the answer
It becomes four times as long
Doubling speed quadruples the distance your vehicle needs to stop, so slow down when conditions call for it.
Source: Illinois Rules of the Road (2026), Chapter 11, Safe Driving Tips: Vehicle Speed (p. 84)
With no other limit posted, what is the limit on an Illinois rural road that is not an interstate or four-lane highway?
Show the answer
55 mph
Rural areas and highways outside the faster groups default to 55 mph.
Source: Illinois Rules of the Road (2026), Chapter 4, Traffic Laws: Speed Limits (p. 24)
A highway in Illinois has a posted minimum speed. When may you legally drive below it?
When safety makes it necessary Whenever you are in the right lane When you are on a short trip Whenever traffic around you is light Show the answer
When safety makes it necessary
Driving under a posted minimum is illegal unless it is needed for safety.
Source: Illinois Rules of the Road (2026), Chapter 9, Roadway Signs: Speed Limit (p. 66)
With no other limit posted, what is the speed limit on a four-lane Illinois highway?
Show the answer
65 mph
Four-lane highways default to 65 mph in Illinois. Interstates and tollways default to 70 mph.
Source: Illinois Rules of the Road (2026), Chapter 4, Traffic Laws: Speed Limits (p. 24)
With no other limit posted, what is the speed limit in an Illinois alley?
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15 mph
Alleys have the lowest default limit in the Illinois list, at 15 mph.
Source: Illinois Rules of the Road (2026), Chapter 4, Traffic Laws: Speed Limits (p. 24)
Children are present in a posted Illinois school zone at 10 a.m. on a school day. What is the speed limit?
Show the answer
20 mph
Illinois school zones drop to 20 mph when signs are posted and children are present during school-day hours.
Source: Illinois Rules of the Road (2026), Chapter 4, Traffic Laws: Speed Limits (p. 24); School Zones (p. 25)
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Full practice test All topics, as in the knowledge test Road Signs What signs mean and what to do when you see them Right-of-Way Who goes first at intersections, crosswalks and roundabouts Traffic Signals Lights, arrows and pedestrian signals Lanes & Turns Lane markings, turns, passing and merging Parking Curb colors, hills and where you can't park Safe Driving Following distance, weather, night driving and sharing the road Alcohol & Drugs Blood alcohol limits, DUI rules and medication Emergencies Breakdowns, emergency vehicles and railroad crossings License Rules Permits, restrictions for new drivers and points Insurance & Collisions Required coverage and what to do after a crash Phones & Distraction Phone rules and other distractions
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About these questions
We wrote these practice questions from the facts in the Illinois Rules of the Road (2026 (DSD A 112.47, printed July 2026) edition) and from official sources on road signs. Every answer links to its source, so you can check it and read more.
DMV Decoded is an independent guide, not a government agency. This practice test is not connected to the Illinois Secretary of State, and your actual test will have different questions. Study the handbook, and check the agency's website for current rules.
