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Speed Zones

A speed zone is a section of roadway with a different posted speed limit than the statutory speed limit. The Ohio Department of Transportation (ODOT) must approve speed zones that lower speed limits on all state, federal, interstate, and local roadways. Speed zones to raise speed limits can, in some cases, be accomplished by local municipalities, without ODOT's approval.

Guidance on speed zones is established in Section 4511.21 of the Ohio Revised Code (O.R.C.).

See more information on speed zones below. Click here or use the green button on this page to view journalized speed zones.

How and why are speed zones set?

It is important that set speed limits are considered reasonable by a majority of drivers. Studies have shown that most drivers tend to drive at a speed with which they are comfortable, so raising or lowering the speed limits does not have a significant effect on speed. However, when the speed limit is set at a level that most drivers consider reasonable, the speed of vehicles is more uniform, which has proven to be a safer traffic pattern.

When doing speed zone studies ODOT considers various factors such as the development of the area, roadway features, traffic volume, accidents, and the speed vehicles are traveling.  Both the 85 percentile speed and the 10 mph pace are very important factors. The 85 percentile speed is the speed at which 85% of the vehicles are traveling at that speed or lower, while the 10 mph pace is the 10 mph range of speeds containing the greatest number of observed speeds.

Speed zones on local roadways

ODOT must approve speed zones for roads and streets to have speed limits set lower than the statutory prima-facie speed limits given in the Ohio Revised Code, regardless of jurisdiction.  This includes rural state highways, county and township roads, and streets in both cities and villages. However, a board of trustees has the authority to lower the speed limit without ODOT approval on a road that is an "unimproved highway" or is in an area that meets the Ohio Revised Code definition of a commercial or residential subdivision. 

While both cities and villages are required to have ODOT approval to have a speed limit lower than the statutory prima-facie speed limits given in the Ohio Revised Code, they can raise speed limits on their streets without ODOT approval. The Ohio Revised Code states in part, "Local authorities in their respective jurisdictions may authorize by ordinance higher prima-facie speeds than those stated in this section upon through highways, or upon highways or portions thereof where there are no intersections, or between widely spaced intersections, provided signs are erected giving notice of the authorized speed, but local authorities shall not modify or alter the basic rule set forth in division (A) of this section or in any event authorize by ordinance a speed in excess of fifty miles per hour."