Methodology for Collecting Vehicle Occupancy Data on Multi-lane Interstate Highways

A before and after comparison of vehicle occupancy distributions for the Atlanta, GA I-85 high occupancy vehicle to high occupancy toll lane conversion, will assess the changes in vehicle and person throughput associated with lane conversion. The occupancy data collection methodology for high-speed freeways was developed after evaluating previous vehicle occupancy data collection methods, evaluating the physical characteristics of the I-85 corridor, and testing a variety of equipment/manpower for the field deployments. The field deployment plans are also discussed in this paper, including site selection and data collection schedules. A consistency analysis was conducted by collecting parallel occupancy data with two observers and equipment on several lanes. The parallel data is paired using the vehicle occupancy recorded pattern and the time stamp difference between the two observations and compared to determine the consistency of the occupancy methodology between the two corresponding observers. Results indicate through the consistency analysis that the proposed vehicle occupancy methods and the training associated with the project minimize the variation of the data collection results among individual data collectors.