Research Report
Robert Krile, Andrew Landgraf, and Elizabeth Slone
Apr-19
Vehicle occupancy factors (VOF) and percent of non-single occupancy vehicle (NonSOV) travel are important considerations for transportation planners and policy makers. A methodology is proposed to estimate VOF and NonSOV based primarily on police records of occupancy from crashes. These data may be biased due to non-representativeness of occupancy in crashes compared to that of all driving. The bias is proposed to be corrected with post-stratification weighting and an occupancy bias correction from historical data. VOF and NonSOV were estimated for 10 years for all states and urbanized areas with a population of at least 200,000 using national records from the Fatality Analysis Reporting System (FARS). Crash records from individual states were utilized for estimates of seven pilot states and their urbanized areas. Validation checks were conducted for these estimates. The computer code used to generate the estimates is provided. The development of credible VOFs and NonSOV from crash records was accomplished on this task. There were certain limitations to the approach that could not be immediately overcome and some potential future limitations. With appropriate documentation of these issues, the general methodology is recommended to be implemented with state-based crash records as the primary source, where available, and the FARS system otherwise.
Link not available.
Vehicle occupancy factor
non-single occupancy vehicle travel
FARS
SDS
HSIS
HSIS Summary Reports are two to eight pages in length and include a brief description of the issue addressed, data used, methodology applied, significant results, and practical implications.
A variety of research studies have been performed using data from HSIS. Many of the final reports prepared are now available electronically.
Research reports are often summarized in executive summaries, technical briefs, or other abbreviated formats. Included here are those road safety summaries that involved research using HSIS data.
In addition to conducting research, HSIS resources are also used to develop products that can be used by practitioners in the analysis of safety problems.
HSIS data are sometimes used in research studies that result in other types of finished products, such as dissertations, theses, and conference proceedings.