Saw this picture (I believe a Matthew Daly shot) and was curious what the bubble on top the Chief's car was. Most likely the 13 BCView attachment 11739
The car i believe was the Safety Bn Rig & the domes on top were some sort of communication experiment or field test.....the fellow in the wheelchair was a disabled FF/Buff (from upstate NY) who spent a lot of time at the WTC site after 9-11.