What's the big question the author is posing here? How would you interpret the story with that in mind?

Ray Bradbury’s short story “The Pedestrian” tells the story of a dystopian future in which television has come to dominate the world. The story’s protagonist, Leonard Mead, is an author; although we learn that “he hadn’t written in years” because “magazines and books didn’t sell anymore.” Throughout the short story, Leonard exists outside of the his society's culture of production and consumption; "The Pedestrian" reveals a horrifying post-human condition in which people exist only to work and to watch television. In this eerie tale, Bradbury seems to question whether technological advancements are ultimately helpful or dehumanizing. Keeping this larger question in mind, we can look for evidence of technology's dehumanizing influence as we read the story.
Although we learn that Leonard is not the only human alive, we do not encounter anyone else throughout the short story that is human in the traditional sense. There is some ambiguity surrounding Leonard’s encounter with the police, which is represented not in the form of human officers but instead as a car with a “phonograph voice.” The ambiguity of this encounter is significant: in the story’s age of the television, people have become machine-like, conditioned by technologies such as the television and the phonograph. In this futuristic society, human police officers are no longer needed—in fact, the population's obsession with television has rendered a police presence largely unnecessary. Technological advancement has given rise to a robotic police car, but this advanced piece of technology cannot recognize nor understand human impulses—for example, Leonard's decision take a nighttime stroll. Ultimately, the robot car labels Leonard's human tendencies "regressive" and carts him away, highlighting the dangers of technology's dehumanizing effects. 
Bradbury depicts a post-human condition that is apocalyptic in nature: Leonard does not encounter another person throughout the story, and we only know that they exist at all because their homes are “ill-lit by television light” and Leonard recounts the daily traffic on the highway. This traffic, produced by workers going to and coming from their jobs, is presented through grotesque imagery:

During the day it was a thunderous surge of cars, the gas stations open, a great insect rustling and a ceaseless jockey for position as the scarab beetles, a faint incense puttering from their exhausts, skimmed homeward to the far directions.

Culture has been reduced to workflow and television—or put differently, production and consumption. These patterns reduce the people around Leonard into something that is not quite human—something that is machinelike. Ultimately, Leonard’s rejection of these patterns is what marks him in the story as regressive.