The aim of this study was to examine and compare psychological factors influencing car drivers’ and motorcycle riders’ speeding intentions (IN), using the Theory of Planned Behaviour (TPB). The psychological factors modules included Attitude (AT), Subjective Norm (SN) and Perceived Behavioural Control (PBC). These were employed to explain speeding intentions in urban road environments. A sample of 188 car drivers and 174 motorcycle riders were collected from the two universities within Khon Kaen, Thailand. The Structural Equation Model (SEM) was used to examine and explain speeding intentions. The results indicated that the TPB could explain 33% and 41% of the variance of intentions by car drivers and motorcycle riders, respectively. The most significant psychological factor for car drivers was determined by attitude (AT), while the speeding intention of motorcycle riders was attributed to perceived behavioural control (PBC). The authorities in Khon Kaen Province should determine safety policies that can improve these psychological factors, which could have various effects or outcomes on changing car drivers’ and motorcycle riders’ speeding intentions. The outcome of this study could help to understand car drivers’ and motorcycle riders’ speeding intentions in urban road environments and it could be useful for development of safety measures. |