It's easy to get lost when you leave the car and start walking around in California. We took a wrong turn on the way to a place to have breakfast and ended up crossing some train tracks and running into the 101, which is an impassible obstacle for foot traffic.
(Though the freeway is not impossible to navigate by foot--on a recent trip to LA, I saw a friend of a friend run across five lanes of traffic on the 101 to rescue two bags of luggage that fell off the roof of our van into the car pool lane. He rescued one bag intact, and, amazingly, retrieved the contents of the second which were spread over several lanes after it got hit by a car. He was then trapped on the center concrete divider, but some friendly person stopped in her car to give him a lift to safety. The whole situation made me think of Concrete Island.)