Injury severity analysis of commercially-licensed drivers in single-vehicle crashes: Accounting for unobserved heterogeneity and age group differences

Interpreting risk factors for truck crash severity on mountainous freeways in Jiangxi and Shaanxi, China

“…With respect to the environment conditions influence, our results also confirmed findings by previous studies indicating that the probability of more serious outcomes of truck crashes increases during the summer and winter days and under adverse weather conditions. This is also consistent with numerous previous studies showing the strong relationship between the season and weather conditions and the crash severity [1,3,4,10,12,16,19,23,26]. Naturally, the rainy weather condition typically occurs during the days of summer season, while foggy and snowy weather conditions usually occur in the cold months of late autumn and winter within the mountainous areas in China.…”

“…The most interesting findings in this study lie in the contributions of the risky driving behaviors of truck drivers to the severity of crashes. Speeding was found to be associated with more fatality crash outcomes in accordance with previous findings [1,3,5,[12][13][14]19]. It was clear that excessive speed decreased the ability of truck drivers to react to unexpected road hazards ahead of time, especially under adverse weather conditions or during the period from midnight to dawn, which increased the chance of crashes.…”

“…However, this finding is inconsistent with that of other similar studies conducted in Jiangxi and Shaanxi, China [1,3], which suggested that keeping a safe distance was instead a major cause of truck crashes that correlated with these two freeway segments in mountainous areas rather than a universal issue of regional roadway networks. Noteworthy, failing to wear a seatbelt was related to higher injury probability in line with previous findings [3,10,13,19]. However, although seatbelt use significantly reduces the fatality probability in truck crashes, the drivers of heavy trucks are not willing to wear seatbelts [21].…”

“…After the analysis of 1787 truck crashes in Tennessee (USA), certain variables, such as posted speed limits, annual average daily traffic (AADT), lane width, degree of horizontal curvature, terrain type, median type, right side shoulder width, etc., were found to have significant effects on the likelihood of such crash occurrences [18]. Additionally, collision partner(s), existence of tunnels and bridges were also identified to be significantly correlated with the truck crash occurrence [1,4,5,11,12,19].…”

“…In recent years, the logit-based and ordered probability regression models have often been applied to analyze the injury severity of truck-involved crashes [1,4,6,9,11,12,[14][15][16]19]. However, these approaches assume that the effect of each parameter remains constant across all observations, which indicates that these approaches cannot capture the potential correlation between truck crash severity outcomes and unobserved effects related to driver, vehicle, roadway, and environment conditions at the time of the crash.…”