How did America's anti-'jay'walking atmosphere get its start?
[C]ar lobby groups ... started taking over school safety education, stressing that "streets are for cars and children need to stay out of them". Anti-jaywalking laws were adopted in many cities in the late 1920s, and became the norm by the 1930s.
[T]he cultural ascendancy of the car was secured as the auto industry promoted "America's love affair with the automobile". Car makers portrayed them as the ultimate expression of personal freedom, an essential element of the "American dream".
Some interesting statistics:
The UK is among those countries where jaywalking is not an offence. But the rate of pedestrian deaths is half that of the US, at 0.736 per 100,000 inhabitants in 2011 compared to 1.422 per 100,000 in America.
Read this article to get a good understanding of at least some of the background to the U.S.'s, *ahem*, uncomfortable walking environment...