Walking up to someone on the street you don't know and talking to them is pretty normal here in the U.S.

In many countries around the world this doesn't happen except in extreme emergencies. But, in general people in the U.S. are more casual about this especially in places like the California coast.

However, there is more separation by race on the East Coast of the United States for some reason whereas almost any white person or black person would be comfortable enough to talk to a stranger on the streets on the coast in California. So, this sort of thing is very regional in nature but generally speaking people are more open to talking to you, especially if you need directions or something like that. But, you are more often likely to receive the correct information in places like California, Oregon and Washington just because that is the way people are out west. We tend to  more friendly in a superficial way and will talk to a stranger more than most places in the country. However, just remember West Coast people are generally much more mobile and well traveled worldwide than most other people in the U.S. except for places like New York and Chicago and places like that. So, there is definitely an International feel more in California than most other places in the center of the country and you are more likely to see many more people from other countries in Los Angeles and San Francisco (especially from the Pacific and Asian regions of the world). So, there are places in San Francisco called by locals 'Chinatown" and 'Japan Town" in San Francisco and I know there is a "Japan Town" also in Los Angeles.