This paper presents the results of an investigation into the effect of changes in location of freeway traffic sensors on incident detection. The study was performed with a microscopic freeway computer-simulation model called Integrated Traffic Simulation (INTRAS). Two measures of effectiveness were employed in the study--the detection ratio and the average time to detect (assuming that detection occurs). Consideration was also given to false alarms. A total of four geometric features was studied:(a) main-line sections,(b) weaving sections,(c) lane drops and additions, and (d) changes in vertical and horizontal alignment.