How does Ray Bradbury use sensory details to show isolation in "The Pedestrian"?
Sensory details, as the term implies, convey information using the five senses: sight, sound, touch, taste, and smell.
"Silence" is repeated twice in the first paragraph. As he walks, Mr. Mead sees "dark windows" in the houses and cottages. If silence indicates that no one is out on the streets, dark windows are a desolate sign that nobody is at home—or, as we find out later, people are watching their viewscreens, cut off from other people.
Bradbury pictures Mr. Mead as a "lone figure" walking down the street.
A particularly vivid sensory image describes the deserted highways, comparing them to dried streams:
But now these highways, too, were like streams in a dry season, all stone and bed and moon radiance.
The police car that takes Mr. Mead away is empty. Mr. Mead's house is the only one lit up, emphasizing its isolation from its gray neighbors. In the last paragraph, Bradbury repeats the word "empty," describing empty streets and sidewalks once again, and uses the word "chill" in the last sentence, meaning both the chill of November weather and the chilly emotion one can feel when all alone.
The first detail is in the first sentence. The city is silent. Since people make noise, that means that there's essentially no one out. This is reinforced a few lines later when readers are told that Mead is "as good as alone" in the world.
That means that he is the only person alive--or at least, the only person outside of a house--who sees/feels the mist of the evening, feels the uneven sidewalk "buckling," feels the frost of the air, etc.
Look at how specific these details are. That too creates a sense of isolation: Mead sees the world more vividly than anyone else in the story (which would be anyone else in the world, functionally).
In the second paragraph, you see that Mead's habits are uncommon, and the details reinforce this. He goes to the graveyard, and sees "phantoms." They are "sudden" and "gray." That's rare, and he's the only one who sees them. That's true isolation.