Federal Investigation of the Evacuation of the World Trade Center on September 11, 2001.
Federal Investigation of the Evacuation of the World
Trade Center on September 11, 2001.
Averill, J. D.; Mileti, D.; Peacock, R. D.; Kuligowski,
E. D.; Groner, N.; Proulx, G.; Reneke, P. A.; Nelson, H.
Pedestrian and Evacuation Dynamics 2005. 3rd
International Conference. Proceedings. September
28-30, 2005, Springer-Verlag, New York, NY, Waldau, N.;
Gattermann, P.; Knoflacher, H.; Schreckenberg, M.,
Editor(s), 1-12 p., 2007.
evacuation; people movement; World Trade Center;
investigations; occupants; occupant behavior; human
behavior; egress; stairwell; elevators (lifts);
mehtodology; statistics; high rise buildings;
simulation; damage; human response; human performance
This paper presents the findings of the NIST World Trade
Center Investigation describing the occupant evacuation
of WTC 1 and WTC 2 on September 11, 2001. The egress
system, including stairwells and elevators, is described
along with the evacuation procedures. The population in
WTC 1 and WTC 2 on September 11, 2001 at 8:46 a.m. is
enumerated and described, where the background of the
population was relevant to the subsequent evacuation,
including training, experience, mobility status, among
others. The progress of the evacuation of both towers is
described in a quasi-chronological manner. A decedent
analysis explores where occupants were located when each
tower was attacked. Multiple regression models were
built to explore the sources of evacuation initiation
delay (why people did not immediately start to leave the
building), as well as stairwell evacuation time (how
long the average occupant spent in the stairwells per
floor). Issues identified as contributing to either
slowing or aiding the evacuation process were explored.
Egress simulations provided context for estimating how
long WTC 1 and WTC 2 would have taken to evacuate with
different populations, using three different models, and
subject to different assumptions of damage to the