DHS has a significant presence at many transportation infrastructure choke points as well as energy/resource infrastructure. It makes sense... an undefended tunnel or bridge would be easy to disrupt and could cause chaos. Note also the ~6+ (NYPD, NY State police, NJ State Police, MTAPD, PANYNJPD, NY National Guard, US Coast Guard, probably ICE since the ramp-up) law enforcement/defense organizations with a presence around the Hudson River crossings.