Every driver has complained about speed limits at one time or another. But who determines those speed limits and how? Speed limits are determined by using the “85 percentile” method. In this method, traffic engineers set the speed limit based on the speed that 85% of drivers would travel at when there is no speed limit. For example, if 85% of vehicles on a residential road with no current speed limit travel at or below 30 miles per hour, that would be the appropriate speed limit. However, on highways:
The Florida Legislature authorized the Florida Department of Transportation to establish speed limits on state highways up to the following maximums: 70 mph on Interstates, 65 mph on a four-lane divided highway outside an urban area (with a population of 5,000 or more), and 60 mph on other state highways.
It is important to obey these laws for your safety and the safety of others. For more information, visit this FAQ