<div class="htmlview paragraph">This paper begins with a discussion of the various types of risk behavior found in automobile driving. A model is proposed which describes a perceptual approach to risk acceptance in specific driving manuevers.</div> <div class="htmlview paragraph">Risk acceptance in lane merging within freeway construction zones is discussed and exemplified by field observations of merging in construction zones. The short gaps accepted led to an experimental study to examine gap acceptance thresholds and driver gap estimation capabilities. Studies were conducted both staticly and dynamicly at 55 miles per hour. Subjects elect short gaps (under 100′) and gaps with less than 1 3/4 seconds at 55 miles per hour. Shorter rear gaps are accepted than front gaps. Gaps are grossly underestimated in both static and dynamic experiments. No difference was found for left vs. right merges and use of mirror vs. direct vision for rear gap estimation. The experimental data was consistent with field observations.</div>