Median barriers are usually constructed to reduce head-on-crashes between vehicles on undivided highways and the type (e.g., cable, metal beam, concrete) based on state requirements for crash mitigation. Because of their position in the center of the traveled right-of-way, median barriers could affect wildlife movement across the right-of-way, decreasing wildlife connectivity. We used previously collected and newly collected wildlife-vehicle collision (WVC) observations to test whether or not median treatments have different effects on unsuccessful wildlife crossings of the road surface. Our primary findings were that there are effects of median treatments on rates of WVC and that these effects varied by species and to some degree by geographic region (represented by Caltrans District). The primary finding was that fewer wildlife enter roadways and are killed in the presence of constructed median types than other types. Although this may result in a reduction in WVC, it also results in a reduction in wildlife permeability as most roadways do not have crossing structures and therefore attempts at wildlife permeability will be across the road surface.

The WVC data we used can be found below as a zip file. Other data are available through public sources not controlled or owned by the REC.