Construction on the Backgate Interchange Project started Monday morning.
The Horry County spokesperson says crews are working from the outer perimeters and working their way in.
She says the work won't slow anything down for several month.
The speed limit along Highway 17 Bypass in the construction area will be reduced to 45 miles per hour.
Horry County officials urge drivers to find an alternate route while construction of a bridge over 707 is underway.
The State's Department of Transportation says all lanes will be open during the day, with occasional lane closures in place at night.
The project is expected to be completed in August 2014.