Time Series Analysis of Highway Work Zone Crashes in North Carolina

Highway work zones present significant safety concerns. This study aims to identify spatial and temporal factors that affect the number of highway work zone crashes in North Carolina (NC). The data from 2000 to 2020 were provided by the NC Department of Transportation (NCDOT). Descriptive statistics, exploratory analysis, and time series analysis were employed. It was found that crashes occurred most frequently in construction-related work zones, work zones with ongoing activities, during clear weather conditions, dry surface conditions, daytime, and right next to the work area. The time series analysis identified multiple trends and a seasonal pattern for monthly crash frequencies, which were used to develop a Holt-Winters time series crash prediction model. The model findings indicate that the crash trend and seasonality are important factors in highway work zone crash modeling along with geometric (e.g., lane width) and traffic variables (e.g., volume).