There is a concept in the law which is called the " Sudden Emergency Defense ". The sudden emergency defense recognizes that when an individual is confronted with an emergency that is not of his or her making that is sudden and requires an immediate response, that the reaction of the person would not be as careful as that of an individual that had more time to react and because there was not the presence of an emergency. Many people mistake the concept of a true, sudden emergency - a situation that arises suddenly and without any behavior on behalf of the driver, with a stipulation that they "suddenly realize exists". In other words, examples of a sudden emergency are a vehicle in front of you suddenly loses control and it goes into a spin, a vehicle in front of you suddenly crossing the center line into your lane, an animal running across the road without any notice. However, if there is a vehicle stopped in the road or stopping in the road with brake lights on and then the driver driving behind "suddenly" realizes the existence of that driver, that is not a sudden emergency. Suddenly realizing the existence of something that was there to be seen but was negligently not seen is not the same as the sudden development of an emergency through no fault of your own.
When confronted with a situation that resulted in a sudden emergency, whether it be the discovery of debris on the road that resulted from cargo falling off a passing vehicle or other factors that could cause continuing dangers for others, it would be prudent to contact the police to advise them of the danger so that they could be eliminated to ensure the safe passage of others.