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 In 1995 Congress repealed the national speed limit of 55 and it is now up to states again to determine the limits.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.
Current speed limits are: 10 km/h (6 mph) in parking lots and residential areas; 60 km/h (37 mph) in streets with no speed limit; 60â80 km/h (37â50 mph) on urban arterial roads (ejes, calzadas, beltways and freeways) 80 km/h (50 mph) in avenues with no speed limit; 70â90 km/h (43â56 mph) on rural two-lane roads