Speed limits unposted — Iowa Permit Test

Where no speed limit is posted, the limit in any business district is 20 mph.

Shops bring crowds, parked cars and people stepping into the street, so you must go slowly.

20 mph in any business district

Where no speed limit is posted, the limit in a residential district or school district is 25 mph.

Kids play and walk near homes and schools. A low speed gives you time to stop for them.

25 mph in a residential district or school district

Where no speed limit is posted, the limit in any suburban district is 45 mph.

Suburbs have fewer homes than town but still have side streets and driveways, so the limit sits in between.

45 mph in any suburban district

Where no speed limit is posted, the limit for any vehicle pulling another vehicle is 45 mph.

A trailer pushes on the car when you brake and can sway, so towing calls for a lower speed.

45 mph for any vehicle pulling another vehicle

Where no speed limit is posted, the limit on unsurfaced secondary roads from sunset until sunrise is 50 mph.

Gravel roads are loose, and at night you see less of them, so the limit drops after dark.

50 mph on unsurfaced secondary roads from sunset until sunrise,

Where no speed limit is posted, all trucks on secondary roads are limited to 50 mph at any time of day.

Heavy trucks need more room to stop, and secondary roads are narrow, so trucks get a lower limit.

and for all trucks on secondary roads at any time of day

Where no speed limit is posted, the limit on all primary roads is 60 mph.

Primary roads are built for steady travel between towns, so their limit is higher than in town.

60 mph on all primary roads, urban interstate highways, and secondary roads, including unpaved roads from sunrise to sunset

Where no speed limit is posted, the limit on urban interstate highways is 60 mph.

City stretches of interstate have more exits and merging cars than the open country.

60 mph on all primary roads, urban interstate highways, and secondary roads,

Where no speed limit is posted, the limit on secondary roads, including unpaved roads, from sunrise to sunset is 60 mph.

In daylight you can see a gravel road's loose spots, so the limit is higher than after dark.

including unpaved roads from sunrise to sunset

Where no speed limit is posted, the limit on rural interstate highways is 70 mph.

Country interstates are wide, straight and have few exits, so they carry the highest limit in Iowa.

70 mph on rural interstate highways

If no speed limit is posted, what is the limit in a business district?

20 mph. Shops bring crowds, parked cars and people stepping into the street, so you must go slowly. Iowa Driver's License Manual, p.42: “20 mph in any business district”