In "The Pedestrian," the police officer takes Leonard Mead in for "regressive tendencies." What is meant by this?Does this mean he is going back to...

I think you are moving towards the correct answer. The
issue here is of course the way that Leonard Meed is different from everybody else in
this police-state society, who appear to be happy staying indoors and watching TV. He
has chosen to not be like them and to reject their lifestyle, even though clearly it
puts him in danger. Note how the rest of the people in his world are
described:

readability="13">

Everything went on in the tomblike houses at
night now, he thought, continuing his fancy. The tombs, ill-lit by television light,
where the people sat like the dead, the grey or multicoloured lights touching their
faces, but never really touching
them.

Because Leonard Meed
does not want to stay in his "tomblike" house, watching his screen like "the dead," and
because he wants to walk around at night "for air," when he has no reason to because of
the air conditioner in his house, he is labelled as having "Regressive Tendencies." To
put it bluntly, he doesn't fit in to this frightening dystopian world that Bradbury
creates for us. If you don't fit in and you are not accepted, you are normally locked
up, which is what happens here.