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What is Driver Expectancy? What is a Driver Expectancy Violation?

March 13th 2023

Driver expectancy is a predisposition of drivers to anticipate that traffic flow will occur in a predictable manner based on rules of the road, traffic laws, and uniform traffic control devices. Driver expectancy is further reinforced with driver training and experience. When driving expectancies are met over and over, day after day, the driver’s experience and expectancies are further reinforced. Therefore, driver expectancy relates to a driver’s readiness to respond to common situations in predictable ways that have been successful under previously similar circumstances.

When expectancies are violated, perception-response time may be increased, primarily because of the need to suppress the expectancy in conjunction with the need to detect and identify the expectancy violation. An expectancy violation could cause any of the following: additional situations to be processed; difficulty in recognizing and discriminating situations; suppression of expectation; difficulty in deciding upon an appropriate response; and dissociation, disorientation, and disbelief in the discernment of position, patterns, and shapes. Expectancy influences the speed and accuracy at which a driver processes information.

Furthermore, there are multiple sources of information associated with the process of recognition. Some of the sources include contrast, lighting, anticipation, pattern, and size, otherwise known as CLAPS. These sources of information will be detailed further in a future blog, but the Accident Reconstructionist and Human Factors Expert should be familiar with each of them as it pertains to driver recognition of a roadway/environmental stimulus.

If you have a driver expectancy matter you would like to speak to one of our LISKE Team Experts about, contact us today!


LISKE is an established leader in the field of accident and injury reconstruction with over thirty years of customer trust. We are dedicated to providing a principled and unparalleled customer experience and continue to strive for excellence, acting with integrity, thoroughness, and accountability. The high-level approach we take to each assignment ensures that no element of causation is overlooked, and no stone is left unturned. Our multi-disciplinary team of scientists, engineers, and ACTAR accredited reconstruction experts prepare a comprehensive, objective, science-based analysis of each accident, powered by next-generation technology. A LISKE accident and injury reconstruction provides a foundational pillar you can count on, whether as a building block to causation, or in the rebuttal to an unacceptable, misinformed, and overreached opposition conclusion. Plan your litigation strategy and achieve the best resolution for your client with LISKE Accident and Injury Experts.