Reading several articles on guide dogs for the blind I often found that, when it comes to the road crossing bit, they say that the dogs are not trained to pay attention to the crossing lights or the beeper some crossings are equipped with, they rather look at the changes in traffic movement. Anyone knows how do they train the dogs to "look for cars" before crossing?
Edit: I'm aware that there is a command given by the handler but my question is about how they get taught to evaluate the traffic after the command is given. This is an example of the various things I read (from guidedogsofamerica FAQ page):
Q: I heard that dogs are color blind, so how do they know when the light turns green so they can cross the street?
A: Guide Dogs do not read the lights nor make the decision to cross the street. It is the guide dog user that gives the command to go forward. First the guide dog user listens for the traffic. When the guide dog user determines it is safe to go forward, they give the command and cross the street. If the guide dog determines it is unsafe to cross the street when it is given the command, it will “intelligently disobey”. This might happen if the guide dog user misjudges the traffic or if a motorist suddenly comes around a corner speeding. In many cases, guide dogs have saved lives because they have protected their partners from dangerous situations involving unsafe motor vehicles.