Statistical modeling of traffic crashes has been of interest to researchers for decades. Over the most recent decade many crash models have accounted for extra-variation in crash counts?variation over and above that accounted for by the Poisson density. The extra-variation ? or dispersion ? is...

The present study evaluated the effect of impactable signs that used the yield-symbol as approved by the National Committee on Uniform Traffic Control Devices (NCUTCD) in the 2003 Manual of Uniform Traffic Control Devices (MUTCD). Impactable yield signs are low- costsignsconstructed of flexible...

Abstract: The Insurance Institute for Highway Safety mailed an essay written by Richard Retting and Sergey Kyrychenko (IIHS, 2005) to many universities and individuals where they accused my coauthor and me of being Junk Scientists. This has become a typical pattern for the IIHS, attacking every...