Background: Traffic events are the second most common cause of mortality and the first cause of years of life lost (YLL) in Iran. Objectives: The aim of this study was to determine the survival of patients with traffic injury and evaluate hospital care quality using the trauma and injury severity score (TRISS) method. Methods: This cross-sectional study was conducted on 1000 patients aged 1 to 89 years old who were hospitalized in two university hospitals in East Azerbaijan, Iran. Patients were selected by using stratified sampling. Data were extracted from medical records and analyzed by STATA11 software. Injury severity score (ISS), revised trauma score (RTS), and expected survival were calculated using the TRISS software package. W-scores and Z-scores were calculated to evaluate the performance of hospitals. Finally, results were compared to those of the major trauma outcome study (MTOS). Results: Among 1000 patients, 246 (24.6%) were female. The mean age was 32.6 years (SD, 18.6). Mean ISS for living patients was 12.4 (SD, 4.3) while it was 36.9 (SD, 8.9) for fatal cases. The average RTS was reported to be 7.1 and 4.35 for alive and fatal cases, respectively (P < 0.001). Based on TRISS, 58 cases were expected to result in death; however, 65 fatalities were observed (65/1000). The W-score was -7 per 1000 and Z-score was + 0.02. The TRISS misclassification rate for survival status of patients with traffic injury was reported as 2.6%. Conclusions: Our findings indicate that the quality of care at the hospitals under study using the TRISS method was lower than the quality of care in the MTOS study. Further, survival of traffic injury patients was clearly influenced by the quality of hospital services provided