Suddenly, the routine trip to the store, the daily delivery, the trip with the family, can turn into a sort of twilight zone of disbelief, where complacency is shattered and the consequences can be a nightmare. How it happens The first instinct when investigating accidents such as the one that killed Curnoe, is to look for some dramatic impairment in the driver such as alcohol or drugs. If this isn't found, then the search shifts to the driving environment, for some anomaly that might have fooled the driver or caused vehicles to go out of control. In both of these areas, the science of Human Factors has much to offer. Most critical in understanding the problem of accidents is understanding that drivers don't necessarily see things just because they're there and clearly visible.
Experience plays a critical role in where drivers look and what they see.
If drivers can easily get the information they need and know what to expect, they can manage themselves in traffic more effectively. And traffic engineers try to oblige. As head of the human factors program for the U.S. Federal Highway Administration, Alexander developed the concepts of Driver Expectancy and Positive Guidance that play an important role in the design of today's highways. But while engineers have made great gains in providing guidance cues for drivers there are still many problems. The down side of making roads and traffic more predictable is the complacency this can engender in drivers.