METHODS: Data from the Arizona Department of Transportation (ADOT) Accident Location Identification Surveillance System (ALISS) for years 2007-2014 were used in the analysis. MVCs were designated on Tribal lands or off Tribal lands using geocoding. Data were analyzed using SAS v. 9.3 (Cary, NC).
RESULTS: A total of 638,971 MVC occurred in Arizona from 2007-2014. Of those MVC, 20,569 occurred on Tribal land with 6,915 resulting in one or more people sustaining injuries and 661 resulting in one or more fatalities. On Tribal lands, 34% of the injuries were passengers as compared to 25% off Tribal lands. A similar pattern was seen for fatalities with 33% occurring among passengers on Tribal lands and 24% off Tribal lands. Single-vehicle MVC were more common on Tribal Lands (35%) compared to off Tribal land (18%). Safety restraint use did not differ on and off Tribal lands. The average number of injuries per crash was 0.54 (95% CI 0.53-0.56) on Tribal lands and 0.47 (95% CI 0.47-0.48) off Tribal lands. The average number of fatalities per MVC on Tribal land was 0.04 (95% CI 0.03-0.41) as compared to 0.008 (95% CI 0.007-0.008).
CONCLUSIONS: This is the first analysis of ADOT ALISS data that compared MVC on Tribal lands and off Tribal lands as two independent populations. MVC that result in injuries and fatalities are disproportionately more likely to occur on Tribal lands in Arizona.