The reduction in speed zones on GA 5, Ga 16/ Alt US27 are all set by the State of Georgia, not the City of Whitesburg. The only speeds set by the City of Whitesburg are those on their city streets. Those streets have to pass an engineering survey by the State of Georgia before they can be added to the permit issued by the Georgia Department of Public Safety to the City of Whitesburg if they want to use radar on those streets. So I seriously doubt that they are illegal as all speed limits are set by engineering data taking into consideration the area a road passes through, ie a school zone, a business area and in the case of the roundabout, the safe speed at which a vehicle can go through the roundabout safely and maintain their lane. Lanes of travel are marked with yellow and white markings. Pass over one of them and you have failed to maintain your lane. Short and simple and it is a violation of the law. Now writing them in the roundabout is stretching it a bit unless the person is just blatently going too fast and goes over the line in my opinion.