Instead, officials enacted a perimeter security plan that can essentially barricade the Capitol facilities in a large square between D streets to the north and south and Third streets to the east and west or close off individual buildings.
Gone is the traffic that once sifted between the Congressional office buildings. Commercial truck traffic around the complex has been banned outright. Officials closed C Street between Washington Avenue Southwest and First Street Southeast, and South Capitol Street and New Jersey Avenue are blocked off between C Street and Independence Avenue.
There, officers now man more than 50 security kiosks, each controlling several retractable vehicle barriers installed in the streets surrounding the Capitol. Large decontamination tents loaded with showers and fire hoses sit adjacent to many of the kiosks.
About 5,000 3.5-foot steel bollards and 1- or 2-foot reinforced gray stone walls now dot and line the campus, replacing unsightly Jersey barriers that were scattered around the buildings immediately after the attacks.
The myriad equipment would be worthless, however, without the personnel to use it.
In the six months following 9/11, the Capitol Police department was stretched thin, with many officers working 72-hour weeks. The National Guard was called in to relieve a tired force.
But lawmakers have steadily appropriated more money to invigorate the department, growing the force from about 1,200 officers at the time of the attacks to the almost 1,800 that guard the facilities today.
“That was the most rapid rise in manpower in the department,” Capitol Police union Chairman Jim Konczos said.
The department incorporated record numbers of canine units and vehicle patrols and upgraded its weapons from modest sidearms to heavy semi-automatic rifles.
Training regimens have also intensified for the force.
Konczos said the Capitol Police department runs regular drills on and off the campus site.
A 41,000-square-foot Cheltenham, Md., facility that was unveiled in 2008 houses scale mock-ups of parts of the Capitol, such as the House and Senate chambers and the Upper West Terrace.
“What’s changed most is the professionalism of the officers up here,” said Senate Sergeant-at-Arms Terrance Gainer, a former Capitol Police chief. “It’s been a sea change in the philosophy of policing. … The men and women are as much anti-terrorist as they are simply giving directions to people.”
Striking changes in security procedures were also heralded in with 9/11.
The anthrax scare sparked new mail-handling requirements, including an offsite mail facility where letters and packages are irradiated.
For lack of a siren on 9/11, officers went door-to-door, urging staffers to evacuate their offices.
But within a week of the attacks, Capitol Police handed down new emergency evacuation plans to Capitol Hill offices, and the measures have been refined ever since. Within six months of the attacks, emergency sirens were functional in the buildings.
“They became more orderly and there was a plan for each building, and I think there was better communication between the police department and the various offices,” said James Varey, Capitol Police chief at the time of the attacks.
The procedures were tested last month when a 5.8-magnitude earthquake struck the area. Sirens could be heard throughout the complex, and Congressional offices were quickly evacuated. The Capitol’s security blockades were raised, and officers surrounded the building, preventing pedestrian and vehicle traffic.
Vice President Joe Biden waits to conduct a mock swearing-in ceremony with Sen. Brian Schatz, D-Hawaii, in the Capitol's Old Senate Chamber, December 2, 2014. Schatz was sworn in to serve the remainder of his term since he was appointed to the seat after Sen. Daniel Inouye, D-Hawaii, passed away.