When that car pulled into the driveway my cat ran to hide under the porch feature of life?

I'm not sure why this would be considered a question. Cats are often scared of changes in their environment, and when something occurs that they do not expect or understand, they will quite often run to a place they consider safe. Under the porch is one such place; dark, out of the way, and somewhat confined, there are fewer directions that she has to worry about being attacked from.