“The problem with prioritizing vehicular travel over all other modes is two-fold. High-speed arterial roadways aren’t just dangerous for people who dare to walk on them; they’re also dangerous because they discourage physical activity. In other words, you’re damned if you walk, and you’re damned if you don’t walk.”
According to this blog post, many of the Metro areas that were ranked the least safe for pedestrians were also the Metro areas that had the least fit people. And vice versa.