FACTORS AFFECTING VEHICLE OCCUPANCY MEASUREMENT

Factors affecting vehicle occupancy measurement were examined with the aim of improving state and local vehicle occupancy monitoring program s. A comparison was conducted of five data sets looking at the effects on average vehicle occupancy (AVO) of time of day, day of week, road types, HOV lanes, locational differences, and traffic volume. It was f ound that AVO was higher in the afternoons, on Saturdays, and on HOV l anes. Inconsistent differences were found for the other variables, tho ugh there were considerable locational variations. Current vehicle occ upancy monitoring programs do not generally take these factors into ac count and, most likely, produce biased estimates of AVO. Suggestions a re made for using these factors in sample designs to represent regiona l and corridor-level vehicle occupancy levels. (C) 1998 Elsevier Scien ce Ltd. All rights reserved.