A few facts keep getting left out: the NWS issued a winter storm warning at 4am telling people that the snow would start mid morning and to stay off the roads. But the temperature dropped even faster than the NWS thought it would. The previous day was warm and the initial snow melted and refroze. Traffic did not help and traffic was going to be bad even without the snow.
Not only that, but the NWS forecast said the storm would remain south of Atlanta, with only a light dusting on the city and little to no snow north. And it was supposed to be just snow.
What really happened was it started as freezing rain, then turned to sleet. The snow followed after 1/4 inch of ice was on all th roads. And Atlanta was in the middle of the storm, not North of it as forecast.
The storm started at mid day, after commuters and school kids were already at work/school. The problems were unavoidable because of this.
All the businesses and schools tried to let out at noon, and the roads became a parking lot, with ice shutting everything down.
There were some computer models out at 0600 hrs that showed the storm moving north, but it was too late.