10 free practice questions on speed limits for the Illinois SOS written knowledge test, each with the correct answer and a short explanation. Study them here, then check yourself in the interactive quiz or the exam simulator.
1. Unless otherwise specified, the speed limit in a residential or commercial area is:
15 mph
✓ 25 mph
35 mph
45 mph
Why: 25 mph is the standard default speed limit for residential and commercial areas, unless otherwise indicated by a sign.
2. What is the maximum speed limit on most rural Illinois interstates and tollways?
55 mph
65 mph
✓ 70 mph
80 mph
Why: Illinois allows speeds up to 70 mph on most rural interstates and tollways, though posted limits can be lower in urban areas or construction zones.
3. On a two-lane highway with no median and no posted speed limit, the default speed limit is:
45 mph
✓ 55 mph
65 mph
There is no limit
Why: 55 mph is the default speed limit for two-lane undivided highways.
4. What can happen to a driver caught traveling more than 100 mph?
A verbal warning only
✓ A significant fine and possible license suspension, regardless of the posted limit
A small fine with no other consequences
Nothing, if no other vehicles were on the road
Why: Driving at speeds over 100 mph is treated as a serious offense in most states, often resulting in steep fines and the possibility of license suspension even on a first offense.
5. The “Basic Speed Law” means that you must drive slower than the posted speed limit when:
You're running late
✓ Weather, traffic, or road conditions make the specified speed limit unsafe
A police officer happened to be nearby
This rule never applies—the specified limit is always safe
Why: The fundamental rule regarding speed requires drivers to travel at a speed that is safe for the current conditions, even if it is below the posted limit.
6. Within 500 feet of a school where children are crossing the street, the speed limit is usually:
15 mph
✓ 25 mph
35 mph
45 mph
Why: Within a 500-foot school zone, the speed limit is usually 25 mph (in certain active zones, it is 15 mph, as indicated by a separate sign).
7. Unless otherwise specified, the speed limit in an alley is:
10 mph
✓ 15 mph
25 mph
35 mph
Why: In alleys, the standard default speed limit is 15 mph.
8. At a blind intersection without signs, the speed limit is:
10 mph
✓ 15 mph
25 mph
35 mph
Why: At an intersection with limited visibility and no signs, the speed limit is 15 mph.
9. When approaching a railroad crossing with limited visibility, you must reduce your speed to 15 mph within:
50 feet
✓ 100 feet
200 feet
500 feet
Why: Within 100 feet of such a railroad crossing, the speed limit is 15 mph.
10. When passing a school bus that is stopped in a designated “safety zone” with its warning lights on, you must reduce your speed to:
5 mph
✓ 10 mph
15 mph
25 mph
Why: The speed limit near the designated safety zone by the bus is 10 mph.