A better question is.. how the hell didn't jack bower get stuck in traffic at all during the course of those two hours? I've been stuck in down town Los Angeles traffic at 7:00 - 8:00.
Even 9/11 didn't kill the inner city traffic (it only lessened Freeway traffic) so I don't think an explination about people being too afraid to work because of the terrorist attacks would explain the lack of traffic.
(I really wish that I recorded that episode since I want to check the locations they we at. I sware I saw Washington and Arlginton Avenue as the cross streets on that Google Map close up. If thats the case then it should have tooken him atleast 5 - 15 minutes to reach the house from the vicinity of the LA River)