Go to Top

Blog Archives

Heydari, S., Fu, L., Miranda-Moreno, L.F., Joseph, L. (2017). Using a flexible multivariate latent class approach to model correlated outcomes: A joint analysis of pedestrian and cyclist injuries. Analytic Methods in Accident Research, 13, 16-27.

Several recent transportation safety studies have indicated the importance of accounting for correlated outcomes, for example, among different crash types, including differing injury-severity levels. In this paper, we discuss inference for such data by introducing a flexible Bayesian multivariate model. In particular, we use a Dirichlet process mixture to keep the dependence structure unconstrained, relaxing the usual homogeneity assumptions. The resulting model collapses into a latent class multivariate model that …Read More

Heydari, S., Fu, L., Joseph, L., Miranda-Moreno-L.F. (2016). Bayesian nonparametric modeling in transportation safety studies: Applications in univariate and multivariate settings. Analytic Methods in Accident Research, 12, 18-34.

In transportation safety studies, it is often necessary to account for unobserved heterogeneity and multimodality in data. The commonly used standard or over-dispersed generalized linear models (e.g., negative binomial models) do not fully address unobserved heterogeneity, assuming that crash frequencies follow unimodal exponential families of distributions. This paper employs Bayesian nonparametric Dirichlet process mixture models demonstrating some of their major advantages in transportation safety studies. We examine the performance of …Read More

Heydari, S., Miranda-Moreno, L.F., Lord, D., Fu, L. (2014). Bayesian methodology to estimate and update safety performance functions under limited data conditions: A sensitivity analysis. Accident Analysis and Prevention, 64, 41-51.

Heydari, S., Miranda-Moreno, L.F., Lord, D., Fu, L. (2014). Bayesian methodology to estimate and update safety performance functions under limited data conditions: A sensitivity analysis. Accident Analysis and Prevention, 64, 41-51.

Fu, T., Heydari, S., Miranda-Moreno, L.F., Fu, L. (2014). Direct and spillover effects of adverse winter weather conditions on speed: A time-series analysis. Presented at the 93rd Annual Meeting of the Transportation Research Board, Washington DC, USA.

Fu, T., Heydari, S., Miranda-Moreno, L.F., Fu, L. (2014). Direct and spillover effects of adverse winter weather conditions on speed: A time-series analysis. Presented at the 93rd Annual Meeting of the Transportation Research Board, Washington DC, USA.

Heydari, S., Miranda-Moreno, L.F., Lord, D., Fu, L. (2014). Bayesian methodology incorporating highway safety manual for fitting and updating safety performance functions. Presented at the 93rd Annual Meeting of the Transportation Research Board, Washington DC, USA.

Heydari, S., Miranda-Moreno, L.F., Fu, L. (2014). Bayesian methodology incorporating highway safety manual for fitting and updating safety performance functions. Presented at the 93rd Annual Meeting of the Transportation Research Board, Washington DC, USA.

Heydari, S., Miranda-Moreno, L.F., Amador, L. (2013). Does prior specification matter in hotspot identification and before-after studies? Transportation Research Record: Journal of the Transportation Research Board, 2392, 31-39.

Heydari, S., Miranda-Moreno, L.F., Amador, L. (2013). Does prior specification matter in hotspot identification and before-after studies? Transportation Research Record: Journal of the Transportation Research Board, 2392, 31-39.