So it's a short story set in (I think) the relatively-near-future about a man walking around at night, and he's pulled up by the cops. Then he's arrested, and I think the idea was that he's arrested for walking around; I think the idea was that it's not a reasonable arrest which makes it, I think, dystopian as well. It was fairly short, I think, and the only other detail I remember was that Ray Bradbury mentioned it as being one part of his inspiration for Fahrenheit 451.
This is probably a short story by Ray Bradbury called The Pedestrian, published in 1951. It’s set in AD 2053, and features (much as you describe) a man walking around at night, alone. He talks to the houses as he walks, asking
“What’s up tonight on Channel 4, Channel 7, Channel 9? Where are the cowboys rushing, and do I see the United States Cavalry over the next hill to the rescue?”
He’s pulled by the last police car in the city, and they ask him a number of questions; what’s his name, what’s he doing outside, whether he has what’s referred to as a ‘viewing screen’. After he answers that he doesn’t, they ask him to get in the car, and then take him to what they call ‘the Psychiatric Center for Research on Regressive Tendencies’. The story ends with an account of the silence in the streets now that he’s gone.
Wikipedia states on the Fahrenheit 451 page that Bradbury
‘expanded the book-burning premise of Bright Phoenix [another of his short stories] and the totalitarian future of The Pedestrian into The Fireman’
which was a novella that he published. He was then
‘urged by a publisher at Ballantine Books to double the length of his story to make a novel,’
and so expanded it into Fahrenheit 451, reportedly taking just nine days to do so.
Hope this helps!