The effects of terrorism events and changes in the US Homeland Security Advisory System on national park visitation

Abstract

ABSTRACT The impacts of terrorism events and the subsequent Homeland Security Advisory System (HSAS) on visitation to US National Park Service (NPS) sites are examined. A spatial random effects model, using a panel of monthly site visitation (1979–2013), spanning the period between two major terrorism events, is applied. Results show increased visitation after the 1995 Oklahoma City bombing, but a decrease in visitation after 9/11. The decline in park visitation diminishes the farther the park site is from the twin towers, and the more time has passed since 9/11. Elevated terrorism threat levels under HSAS have a negative impact on visitation, but the impact of the warning decays over time. The interaction effect indicates that large visitation sites close to the Twin Towers may experience more visitation after the HSAS level increases. We suggest that the negative HSAS time effect may be due to some potential visitors choosing to stay home, while the positive interaction effect may indicate substitution towards visiting NPS sites.