Ethics is two things. First, ethics refers to well-founded standards of right and wrong that prescribe what humans ought to do, usually in terms of rights, obligations, benefits to society, fairness, or specific virtues.
If you mean the average speed limit, it's probably 65 MPH. In 1995 Congress repealed the national speed limit of 55 and it is now up to states again to determine the limits. About 30 states have limits of 70 MPH or higher. A few Western states have no speed limits on certain stretches of highway.
THE DETERMINATION OF A POSTED SPEED LIMIT. In Iowa, several jurisdictions (e.g. the state, counties, and cities) have the authority to establish. speed limits on roadways between 25 and 55 miles per hour (mph). The actual posted speed limit. on a particular roadway, however, is typically established from the results of a traffic engineering. study or survey. In general, these investigations analyze existing roadway conditions, collision. records, and/or the prevailing speed of most drivers.