In most parts of the industrialized world, the streets have been surrendered to motorized vehicles. Many municipalities in the United States make half-hearted efforts to support bicycles as transportation by providing bike lanes to nowhere and hanging signs admonishing the SUVs to "Share the Road" and a few -- downtown San Francisco; Boulder -- do considerably more, but nowhere have they gone as far as Flanders and the Netherlands at integrating pedestrians and non-powered vehicles into the traffic mix. The Dutch even have a name for it: A woonerf is a street that is not closed to cars and buses but one where pedestrians and cyclists have legal priority over motorists.
Here's how urban streets used to look:


As these wonderful movies show (the San Francisco trolley ride is from 1906), when automobiles first arrived on the scene they joined pedestrians, bicycles, horses, buggies and wagons, trolleys and buses in the busy streets. Not only was this mix of uses more pleasant, there is evidence (visit Linda Baker's Salon article for background) that it was also safer than the current surrender of the streets to motorized carnage.

Further reading: Why don't we do it in the road? A new school of traffic design says we should get rid of stop signs and red lights and let cars, bikes and people mingle together. It sounds insane, but it works by Linda Baker (Salon 2004-06-20)