Speed limits — Illinois Permit Test

Unless a sign says otherwise, the Illinois speed limit is 70 mph on interstates and tollways.

Seventy is the ceiling and not a target, because the limit assumes good weather and light traffic. Local governments may post something lower.

Interstates and tollways - 70 mph.

Unless a sign says otherwise, the Illinois speed limit is 65 mph on highways with four lanes.

A four-lane highway without interstate separation gives less room for error, so the number drops. It is the limit people most often carry over from the interstate.

Highways with four lanes - 65 mph.

Unless a sign says otherwise, the Illinois speed limit is 55 mph on other highways and in rural areas.

Rural roads have field entrances, tractors and no shoulder. Fifty-five is what the state sets where nothing else is posted.

Other highways and rural areas - 55 mph.

Unless a sign says otherwise, the Illinois speed limit in city and town areas is 30 mph.

Thirty is the number at which a pedestrian hit by a car usually survives. Every town street starts there unless a sign changes it.

City/town areas - 30 mph.

Unless a sign says otherwise, the Illinois speed limit in an alley is 15 mph.

An alley has doors, dumpsters and children coming out between parked cars. Fifteen is walking pace for a car, which is the point.

Alleys - 15 mph.

The Illinois 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.

All three conditions have to hold at once, which is why the limit is not in force on a Sunday. When they do hold, it is the lowest limit most drivers meet.

School zones - 20 mph (on school days between 6:30 a.m. and 4 p.m. when children are present and signs are posted).

A driver may only drive at the maximum allowable speed under safe conditions, and must slow down when approaching an intersection, going around a curve, nearing the top of a hill or driving a narrow winding road.

The posted number describes a dry road in daylight with nothing happening. The four places named are where the road hides what is coming.

You must slow down when approaching and crossing an intersection, going around a curve, approaching the top of a hill, or traveling on a narrow and winding roadway.

Where no minimum speed limit is posted, a driver should not drive so slowly that it interferes with the normal movement of traffic.

A car well below the flow makes everybody else change lanes around it. Illinois treats that as a hazard, not as caution.

When minimum limits are not posted, you should not drive so slowly as to create interference with the normal movement of traffic.

Local municipalities may post speed limits that differ from the statewide ones.

The statewide figures are the default, not the ceiling everywhere. A posted sign beats what you remember from the book.

Local municipalities have the discretion to post speed limits different from those listed.

What is the Illinois speed limit on interstates and tollways where no sign says otherwise?

70 mph. Seventy is the ceiling and not a target, because the limit assumes good weather and light traffic. Local governments may post something lower. Illinois Rules of the Road 2026, p.24: “Interstates and tollways - 70 mph.”