Driving of motor vehicles - South Carolina

Federal regulations

South Carolina has adopted Part 392 of the Federal Regulations.

Applicability

Part 392 applies to a commercial motor vehicle and its driver, operating in intrastate commerce with a gross vehicle weight, gross vehicle weight rating, gross combination weight, or gross combination weight rating equal to or exceeding 26,001 pounds, or a commercial motor vehicle and its driver, transporting hazardous materials required to be placarded.

Engine Idling

A commercial diesel vehicle licensed for use on a public roadway to transport property or passengers with a gross vehicle weight, gross vehicle weight rating, gross combination weight, or gross combination weight rating of 10,001 pounds or more may not idle for more than 10 minutes in any 60-minute period.

A passenger bus (designed to carry 16 or more passengers) may idle up to 15 minutes in a 60-minute period to provide heating or air conditioning when passengers are on the vehicle.

Exceptions — There is an exception for an occupied vehicle with a sleeper berth for the purpose of heating or air conditioning:

• during a rest or sleep period;
• when the outside temperature is less than 40°F or greater than 80°F; or
• while the vehicle is at a rest area, fleet trucking terminal, commercial truck stop, state designated location designed for the intended purpose of a driver’s rest area, or any location that a vehicle is legally permitted to park that is at least 500 feet from residential housing, schools, daycare facilities, hospitals, or similar locations.

There are also exceptions for:

• traffic conditions;
• operation of defrosters, heaters, air conditioners, cargo refrigeration equipment, or to install equipment to prevent a health or safety emergency;
• emergency and law enforcement vehicles;
• maintenance, servicing, or diagnostic purposes;
• federal and state inspections;
• powering work-related mechanical or electrical operations;
• an armored vehicle when a person remains on vehicle to guard the vehicle’s contents or while loading and unloading; or
• an occupied vehicle while waiting in line or queuing to load or unload.

Speed limit

The speed limit is 70 mph on rural interstates, 65 mph on 4-lane roads, and 55 mph on all other highways.