The traffic metric assesses the effect of road (and railroad) traffic on animal populations due to road mortality. It integrates the distance to and traffic intensity of roads in the neighborhood of the focal cell. The traffic metric (Fig. 1) is an element of the ecological integrity analysis of the Designing Sustainable Landscapes (DSL) project (see technical document on integrity, McGarigal et al 2017). Consisting of a composite of 21 stressor and resiliency metrics, the index of ecological integrity (IEI) assesses the relative intactness and resiliency to environmental change of ecological systems throughout the northeast. As a stressor metric, Traffic values range from 0 (no effect from road traffic) to 1 (severe effect; although in real landscapes, the metric never reaches 1).