Welcome to ROSA P |
Stacks Logo
Advanced Search
Select up to three search categories and corresponding keywords using the fields to the right. Refer to the Help section for more detailed instructions.
Clear All Simple Search
Advanced Search
Omitted variable bias in crash reduction factors.
  • Published Date:
  • Language:
Filetype[PDF-2.41 MB]

  • Corporate Creators:
  • Publication/ Report Number:
  • Resource Type:
  • Geographical Coverage:
  • Abstract:
    Transportation planners and traffic engineers are increasingly turning to crash reduction factors to evaluate changes in road

    geometric and design features in order to reduce crashes. Crash reduction factors are typically estimated based on segmenting a

    highway and associating crashes with geometric features; this allows statistical methods to be applied to the data. Concurrently

    there is a stream of research that relies on spatial units of analysis to examine crashes; these typically use broad features of the

    road network combined with socio-economic and demographic factors that are associated with crashes. In this paper, we

    examine whether omission of these spatial factors in a link-based geometric model results in omitted variable bias. Our results

    suggest that there is no change in coefficient signs, but that there is a reduction in the magnitude of estimates. The sign of spatial

    variables, however, is quite different when combined into a link-based model. We also find substantial variability in coefficient

    estimates, and discuss the implications of these results for the use of crash reduction factors.

  • Format:
  • Main Document Checksum:
  • Supporting Files:
    No Additional Files
No Related Documents.
You May Also Like:
Submit Feedback >