Legal Question in Personal Injury in Texas

You would be considered at fault. I'm not sure whether the law requires that all vehicles have a working horn, but it makes sense that it would. You could argue that the other driver negligently maintained his vehicle and that such negligence contributed to the accident. This assumes that he would have had time to honk his horn and been in a position to see you backing in time to honk. Nonetheless, it's hard to expect that a jury would find him more at fault than you. The percentage of fault that you can place on the other driver, however, will reduce the percentage of how much you would have to pay for his damages.