Here is a question I have not been able to answer from searching the inter web. Our house is located in the rural area outside of the incorporated city limits. 2 Lane road. It used to be posted 25 in town and then as you left to head out my way it was posted 35 and then not posted but known to be 50 mph. (We are in Ohio and the law says that un-posted non-divided is 50) Now they have added another zone where it used to go from 35 to 50. They dropped in posts for 45mph. But there are no begin or end speed limit signs. Anyone know how much distance you have to go with no signs before you can assume it is 50 again?