This article is from the The Terminator FAQ, by Karsten A. Loepelmann firstname.lastname@example.org with numerous contributions by others.
The T-1000 was transported to the Sixth Street Bridge in downtown LA at night
and had access to a police vehicle and John Connor's address. Yet he only
arrived at John's house in Reseda *after* the Terminator did! It seems like
least 4-6 hours between the T-1000 arriving and then getting to John's house.
The greater LA area is big, but not that big.
The most likely explanation is that the T-1000 does not know its way around
very well. In the annotated screenplay, it is revealed that the T-1000 has to
ask the little girls the location of the Galleria!