The crash was only accessible to vehicles via a single residential street. With the surge of rescue personnel who converged on the area, the roads leading to the site soon became choked with traffic. Emergency vehicle drivers abandoned their vehicles counter to established policy in the course of the rescue efforts. This prevented other vehicles from being able to access the crash area. The road was so impassible, many rescue workers left their vehicles miles away and made it to the scene on foot. Fog also grounded rescue helicopters for two hours. As a result, many critically injured survivors were not evacuated until 23:30. Eventually, four helicopters from the New York City Police Aviation Unit evacuated 21 people from the crash site. There were also major problems with communication by rescuers. Radio frequencies became overloaded and authorities on site were unable to make command decisions in some cases. The head of surgery of the Nassau County Medical Center was present at the scene but unable to direct patients to the best locations because many rescuers were radioing the center itself to get advice on where they should send the survivors. Medical professionals on site reported that some hospitals received the most up-to-date information by watching the news coverage. Despite these problems, however, only three of the passengers found alive died of their injuries.