Exploring the Impact of Climate Change on Road Fatalities: A Macroscopic Panel Data Analysis

The present road traffic safety situation faces significant challenges. Examining the influences of diverse contributing factors on road traffic crashes is of crucial importance. However, different factors may have different influences as the change of location and time and the neglect of potential heterogeneity while modelling the frequency of traffic crashes may lead to biases in parameter estimation and incorrect inference. To address the unobserved spatiotemporal heterogeneity and accurately explore the correlations between contributing factors and fatal traffic crashes, a fixed effects panel model with structural breaks is applied to identify the influences of crucial factors on fatal traffic crashes from a macroscopic level. A multisource dataset, including fatal crash numbers, socioeconomic factors, laws and regulations and climate factors is collected from the United States spanning 45 years (from 1977 to 2021). The climate change events (i.e., El Niño–Southern Oscillation phenomena) are examined for their influences on fatal traffic crashes. The experimental results illustrate that high temperatures and frequent meteorological disasters have increasing impacts on fatal crash numbers. High precipitation shows a decreasing one from a macroscope level because of the lagged effect of precipitation on crashes across days. Particularly, the climate change events (including EP E1 Niño, CP E1 Niño and La Niña) represent an adverse impact on road traffic safety. Additionally, the states with similar meteorological characteristics are categorized as high temperature, high precipitation and frequent meteorological disaster subsets for separate analysis. Under these subsets, rural trip proportion becomes a more pronounced factor that affects fatal road traffic crashes, and helmet laws are more efficient in reducing fatal crash frequency. The research findings reveal an increasingly complex road traffic safety environment in the context of global warming, offering valuable perspectives for enhancing road traffic safety.