The joint study, scheduled to be released at noon today at a hearing of the House Science Committee, concludes that the twin towers' ability to remain standing for an extended period following the Sept. 11 attacks was remarkable and that the buildings' strength enabled most occupants to evacuate safely. The robustness of the towers' steel framing, adequate stairways that were well marked and lighted, and tenants' knowledge and use of emergency exiting programs are credited in the study as design features that kept the buildings standing long enough for thousands of people to escape.

While finding that the trade center attacks are a reason to question design philosophies, the report states that there are insufficient data to determine whether the threat of similar attacks is great enough to require that building codes reflect the possibility. The technical feasibility to develop building design provisions that would enable all structures to absorb airplane impact without collapse and the cost of building such structures might be too high, it states.

Instead, the study recommends that resources should be directed primarily to aviation and other security measures rather than to building reinforcement. "The relationship and cooperation between public and private organizations should be evaluated to determine the most effective mechanisms and approaches in the response of the nation to such disasters," notes an executive summary of the document obtained by GlobeSt.com.