Malaysia's economic prosperity is overshadowed by a concerning rate of 19 daily road fatalities. This study aimed to investigate road users' perceptions of road service quality (RSQ) and its association with road traffic accidents (RTAs) on an expressway in Malaysia. A questionnaire-based approach collected data from respondents comprising bikers, motorists, bus operators, and truck drivers. Descriptive analysis indicated that, except for motorcyclists, most road user groups rated the overall RSQ of the expressway as poor. Statistical analysis revealed significant variations in perceptions of road surface among road user categories. Pearson correlation analysis demonstrated strong positive relationships between road surface, road drainage, road maintenance, and RTAs. No significant relationships were found between road furniture, rest areas, and RTAs. Multiple regression analysis revealed that road maintenance, road surface, and road drainage accounted for 7.6% of the variance in RTAs, highlighting their importance as predictors. The Relative Importance Index analysis identified ten influential factors on RTAs, including permanent wave, poor workmanship, water pounding, road settlement, repeated construction, invisible road markings, insufficient traffic signs, potholes and bumps, insufficient street lighting, and oily road surfaces. These findings provide policymakers with valuable insights to enhance road safety regulations and develop effective strategies for improving RSQ and reducing RTAs.