The governing body of every state sets its own statutory speed limits by which drivers must abide. South Carolina is no exception.
The law in South Carolina states that the operator of a motor vehicle must control speed to avoid collisions and avoid driving at a speed that is above what is prudent and reasonable under the conditions. However, because what one driver deems reasonable and prudent may not seem so to another, the legislature has set maximum speed limits for different types of roads.
The maximum speed limit on most roads in South Carolina is 55 miles per hour. However, in urban districts, the maximum speed limit is 30 miles per hour. The law allows local governments to establish speed limits that are lower in response to certain hazards, but it is generally unacceptable to set a speed limit that is higher.
The law goes on to state that the state of South Carolina can set speed limits that are higher than the statutory maximum on roads where the federal government grants it that privilege. This includes interstate highways. Therefore, according to the Insurance Institute for Highway Safety, the maximum posted speed limit on interstate highways, whether urban or rural, that run through South Carolina is 70 miles per hour. Some limited access roads have a posted speed limit of 60 miles per hour.
On roads outside urban districts that do not fall into these categories, over which the federal government has no say, the statutory maximum speed limit of 55 miles per hour applies, even if not posted.