Revealing the speeding principle based on the extended theory of planned behavior

• Extended the theory of planned behavior model by incorporating normlessness, sensation-seeking tendencies, road environment characteristics, and travel scenarios. • Sensation-seeking tendencies directly affect the intention to speed and also indirectly influence speeding intention through attitude. • Road environmental dangerousness negatively impacts speeding intention. • Sensation-seeking tendencies directly affect the intention to speed and also indirectly influence speeding intention through attitude. Driver speeding is one of the main causes of deteriorating traffic safety and is a common problem encountered in traffic safety management worldwide. In this study, structural equation modeling of the influencing factors of driver speeding based on the theory of planned behavior (TPB) model is performed to explore the mechanism of highway driver speeding, and the extended factors of driver normlessness, sensation-seeking tendencies, road environment characteristics, and travel scenarios are introduced. The study collected 463 valid samples via a Web survey method. The model results showed that the extended TPB model can explain 79% of the variation in self-reported speeding behavior. Perceptual behavioral control, time-saving benefits, and attitude are the most important influences of speeding intention, with standardized path coefficients of 0.42, 0.36, and 0.32, respectively. Sensation-seeking tendency and normlessness are the next most important factors, with standardized path coefficients of 0.20. The least influential factor is subjective norms, with a standardized path coefficient of 0.19. The environmental dangerousness of roads negatively affects the intention to speed. The optimal scale model results indicated that shoulder width, slope type, and roadside landscape significantly affect perceived dangerousness, in decreasing order of importance. Increased sensation-seeking tendencies not only directly affect the intention to speed but also indirectly affect speeding intention through attitude, and the mediating effect is significant. This study aims to assist transportation researchers in comprehensively understanding the mechanism of driver speeding, allowing them to gain a new vision for investigating ways to regulate driver speeding behavior.