http://www.usatoday.com/news/nation/2006-07-31-ny-security_x.htm
Martha T. Moore
" In the neighborhood hit by the Sept. 11 attacks, strategies against terrorism have names like "ha-has," Tiger Trap and NOGOs. They are new security features that incorporate protection with architectural design, a step beyond bollards and barricades. Outside the New York Mercantile Exchange, where oil and gold are traded just west of Ground Zero, a long row of bollards will be replaced this fall by a sidewalk punctuated with benches that will conceal a security device called a Tiger Trap: Just below a layer of paving stones is a trench filled with low-density, compressible concrete that will collapse under a heavy weight."
ACROSS THE USA: Redesigns mask security barriers [Arch & Bldg; Counter-terrorism]