Improved Vehicle Occupancy Data Collection Methods

摘要

The report evaluates current and emerging vehicle occupancy data collectionmethodologies. Five primary methods for collecting vehicle occupancy data were identified: the traditional roadside/windshield observation method, a recently developed carousel observational method, photographic surveillance, mail-out or telephone surveys, and accident database extraction method. The findings show that other methods besides the traditional windshield method may be advantageous for collecting vehicle occupancy information. The key factors in selecting a collection method are the conditions under which vehicle occupancy is to be estimated. For example, the accident method and mail-out surveys are well suited for developing regional vehicle occupancy estimates, while the windshield method and carousel method are well suited for corridor-specific estimates. Another key finding, which impact the selection of a method and sampling period, is the fact that average vehicle occupancy estimates vary significantly by time-of-day, day-of-week, and month-of-year. The implications of this finding is that agencies cannot continue to infer yearly AVO estimates from data collected during a limited time period such as the morning rush hour period. Recommendations for selecting and implementing a vehicle occupancy data collectionm method are also provided.