All roads out of New Orleans jammed to a halt?

[Little-Acorn]

This apparently happens every time there's a hurricane.

And yet every time, the authorities tell people to evacuate, when in fact the cars and buses can go nowhere.

Am I wrong here? I'm not in Louisiana myself, thought I've been there in the past. Are the roads actually open and moving freely? All I see on TV are lines of cars stretching to the horizon, and not moving. During Katrina there were tons of stories about cars that idled for hours and hours on the freeways, waiting, and finally ran out of gas in place.

On a freely-moving freeway (60 mph-plus), a hundred or more cars per minute will pass any given point on the road. On the ones TV is showing out of NO, maybe one or two cars per minute, go by. They are that jammed up.

What's the real story? Are the roads jammed to a stop, or not?

ON EDIT:
Some question the wisdom of building a city at that location, with the low elevation (below sea level!) and constant hurricane threat. But look at the geography. The largest, longest river in the nation, used for more shipping and commerce than any other, comes to the sea at that point. There WILL be a major city built there, come hell or high water (an expression that seems custom-made for New Orleans).

But, not only is the elevation below sea level, but it is also DROPPING at around an inch per year.

Maybe after Katrina, they shouldn't have bothered cleaning up, but should have simply bulldozed the entire place flat, then brought in umpteen zilion tons of gravel and fill and raised the elevation of the entire peninsula twenty or thirty feet, and then built all new buildings on pilings that could be extended every 50 years or so, as needed. Fantastically expensive, of course. But was simply rebuilding as it was before, any smarter?