Book excerpt: "This book's title has two parts, "Roadway Human Factors" and "From Science To Application." The first describes its major goal: to analyze driver behavior, especially the causes and avoidance of collisions. In most general terms, the goal is largely to answer a single question: "Why didn't the driver respond sooner?" The cause of most collisions lies in the answer. The book's perspective is psychological. It views roadway events through the eyes of the driver. This contrasts with the third-party god's eye view that appears in accident reconstruction diagrams and other analyses which are primarily based in physics and cookbook science. Physics cannot be ignored, but roadway events can only be explained by examining driver psychology. Drivers act based on their perceived reality which differs from the physical reality of the accident reconstruction diagram. The second part announces its method: the application of scientific research. Specifically, the science in question is experimental psychology. Much of this book reads like an introductory text on experimental psychology, albeit with a distinctly applied slant. This is necessary. There are frequent misunderstandings about the definition of human factors. It is best described as a branch of experimental psychology. Human factors applies experimental psychology data to guide the design of objects and environments so that they that fit human abilities and are easy and safe to use. This book's underlying thesis is that knowledge of the science is a necessary but not sufficient condition for understanding roadway human factors. The key word in the title is "From" because there is a catch-22. Controlled research has inherent characteristics which differ from real-world conditions. Scientific research is generally conducted in highly simplified and artificial situations with unrepresentative subjects and drivers. Scientific research data cannot then be directly applied to the real-world. The step from science to application is far greater than many imagine, probably because there are so few who are well versed in both. The book also introduces areas of science that are unfamiliar to most who investigate collisions. "Ecological optics" is a discipline of perceptual psychology that is key in understanding vehicle guidance and collision avoidance. "Visual psychophysics" is the psychological science that underlies visibility and all other sensory judgments. "Operant learning" is the psychological science of adaptability and behavior change based on the consequences of action. The book also introduces more specific concepts that are important but seldom figured into collision analysis. These include notions such as affordances and action boundaries, system tolerances, crowding, and response conflicts"--