Exploring variations in the influence of various factors on fatal/non-fatal crash outcomes of novice driver involved crashes across diverse urban environments: Insights from partially topic-constrained modeling approach.

Novice drivers present considerable challenges to urban traffic safety. Due to their limited driving experience, they may not be fully acquainted with the diverse urban environments, which can lead to variations in the influence of factors on the crash severities across these urban settings. However, previous studies have primarily considered the urban environment as a potential influencing factor while overlooking these variations. To fill these gaps, this research employed a six-year dataset of novice driver involved crashes in Shenyang (China) and characterized the urban environment by examining the number of various types of public service facilities situated within the buffer zones surrounding these crashes. Additionally, it extracted the topics of the urban environment based on Latent Dirichlet Allocation (LDA) model, with each identified topic representing a distinct category of novice driver involved crashes. Furthermore, the research examined variations in the influence of factors on crash severities across these categories through a partially topic-constrained modeling approach. Results show that the entire dataset was subsequently divided into three topics, revealing significant differences in how factors influenced crash severities within these topics. Specifically, improper operation is observed to increase the likelihood of fatal crashes in areas with low-intensity and service-scarce environment (Topic 1), weekends and speeding are likely to increase the probability of fatal crashes in areas with high-intensity and service-concentrated environment (Topic 2); summer and possessing two years of driving experience are also linked to an increased likelihood of fatal crashes in areas with moderate-intensity and service-dispersed environment (Topic 3).