I use my air horn as to try not to loose my stride. To late of a horn and you brake like you didn't have the horn, too early and the car may not hear it or ignore it, but a well timed horn could make a difference in you continue your stride like no cars on the way. It's an art I haven't fully master. I consider the horn like lights, they are there to help, but they would not avoid a collision of the car that doesn't hear you or decides to ignore you. So you still have to have an avoidance plan, just in case.