Finite mixture modeling approach for developing crash modification factors in highway safety analysis Conference Paper uri icon


  • This study aimed to investigate the relative performance of two alternative models (negative binomial (NB) model and two-component finite mixture of negative binomial models (FMNB-2)) in terms of crash modification factors (CFMs). For a modeling dataset, rural multilane segment crash data for divided highways in California and Texas were used. The resultant CMF function from the FMNB-2 model showed several good properties over the NB model. First, the safety effect of a covariate was better reflected by the CMF function from the FMNB-2 model, since the model takes into account the differential responsiveness of crash frequency to the covariate. Second, the safety effect did not increase continuously without a limit, but leveled off after a certain value of the covariate, which makes more logical sense. However, there was a possibility that a U-shaped relationship could be found, which opens up a new avenue for discussion among highway safety community.

published proceedings

  • Proceedings of the 19th International Conference of Hong Kong Society for Transportation Studies, HKSTS 2014 - Transportation and Infrastructure

author list (cited authors)

  • Park, B. J., Lee, C., Lord, D., & Kim, D. G.

complete list of authors

  • Park, BJ||Lee, C||Lord, D||Kim, DG

publication date

  • January 2014