"It may come down to the intent of the responsible party."

Intent is one thing, ability to execute the plan is something else. Terrorists and other criminals often make really stupid mistakes.

I believe survival near the blast site depends on several things: power of the bomb, if it was detonated at ground level or in the air, etc.

The concussion from the blast is going to make stuff that wasn't vaporized initially turn into dangerous missiles: chunks of building concrete, steel beams, telephone poles, light standards, vehicles, cornerstones, bronze lions, etc. Can you imagine all the parts of of NYC being reduced to chunks of various sizes, moving parallel to the ground at high rates of speed? It would be a truly ugly sight.

Survival would probably depend on sheer dumb luck. The idea of an open street is more than I can imagine. Multiply the crash of the Twin Towers by 50,000, with debris moving sideways.

Sue