Reasonable and prudent limit
Wisconsin law says you must drive within what's called a "reasonable and prudent" limit. That means you not only have to obey the posted speed limit, you must drive a vehicle no faster than is reasonable and prudent under the conditions.
Weather conditions such as fog, rain, ice or snow as well as heavy traffic or congestion mean you have to reduce your speed to the point where you're able to control the vehicle and avoid colliding with any object, person or vehicle.
Other conditions requiring you to slow down are: approaching and crossing an intersection or railway grade crossing, when approaching and going around a curve, when approaching a hillcrest, when traveling upon any narrow or winding roadway, when passing school children, highway construction or maintenance workers or other pedestrians.
Zoned and posted limits
These are the generally established legal speed limits (in miles per hour or MPH) a motorist must obey, and the conditions under which they apply.
Limits may differ from these guidelines when indicated by official traffic signs.
- When passing a school when children are going to or from school or are playing within the sidewalk area near the school.
- When passing an intersection marked with a "school crossing" sign when children are present.
- When passing a safety zone occupied by pedestrians and at which a public passenger vehicle has stopped to receive or discharge passengers.
- On any street or town road, except a state highway or connecting highway, within or near a public park or recreation area when children are going to or from or are playing. This limit applies when the local city or town has enacted an ordinance and posted the limit and where motorists would enter the street from an area where a different speed limit is in effect.
- In any alley.
- On any highway within the corporate limits of a city or village, other than on highways in outlying districts.
- On any service road within the corporate limits of a city or village.
- In any outlying district within the corporate limits of a city or village.
- On any highway in a semi-urban district outside the corporate limits of a city or village.
- On any town road where on either side of the highway within 1,000 feet the buildings in use average less than 150 feet apart. This limit applies when a city or town board has adopted an ordinance determining such a speed limit and has posted signs.
- On any highway designated as a rustic road.
- In the absence of any other fixed limits or the posting of limits as required or authorized by law.
- On any freeway or expressway, when official signs specifying this limit are posted.