Research needs and opportunities concerning human-environmental interactions in crashes involving alcohol.

There has been continuing awareness and concern that alcohol is a drug capable of impairing ability to receive information, to process it in timely and appropriate fashion and to make timely and appropriate responses. One, however, cannot talk about impairment within a vacuum, but rather within the context of the question, impairment for what? It is not enough to say that a car crashed because the driver was impaired by alcohol. Equally important is the following question: If the driver was so impaired and had been so impaired for the past several miles during which the driver had been maneuvering the vehicle, why was there no crash until now? One possibility is that the crash at this moment, as opposed to a previous moment, was simply a random event. Another possibility is that the task became sufficiently more demanding at this moment so that the driver--despite no difference in physiological or psychological level of impairment--was no longer able to cope effectively with data input and processing or in response to the results of those two components of function. It is equally unsatisfactory simply to say that the task became too demanding for a driver impaired by alcohol. One must know which of the several possible components of task demand became excessive and why. Some of these unexplored issues are the subject of the first part of this paper. The second part examines research questions concerning human-environmental interactions during the crash or injury phase.