Safety belt use on tribal reservations subject to tribal law and tribal traffic law enforcement was observed between September and November 2004 (15 reservations) and in February 2005 (1 reservation). Overall, 44 percent of the vehicles were cars, 31 percent were pickups, 14 percent were SUVs, and 10 percent were vans. Fifty-eight percent of the drivers were male, 38 percent were female, and the sex of 3 percent could not be determined (does not sum to 100 due to rounding). Fifty-three percent of the passengers were female, 37 percent were male, and the sex of 10 percent of the passengers could not be determined. Belt use could be coded for 90 percent of the drivers and 83 percent of the passengers.

For the tribal reservations subject to tribal law and tribal traffic law enforcement, excluding the Navajo, the overall safety belt use rate was 55.4 percent. There was a very high variation in belt use across reservations, ranging from a low of 8.8 percent to a high of 84.8 percent.

There were significant differences in belt use by vehicle type and occupant sex for drivers and passengers, consistent with patterns seen in State and national belt use results. Rates were higher for cars (58.8%), SUVs (62.1%) and vans (57.5%) and much lower for pickup trucks (48.1%).

Males were less likely to use safety belts than females, 52.3 percent versus 60.3 percent. Drivers were somewhat more likely to be belted, at 56.6 percent, than passengers at 51.3 percent were. The lowest overall belt use rate was for male passengers in pickups, at just 39.1 percent. The highest rate was for female drivers of SUVs, 67.7 percent belted.

Belt use also varied consistently with road type. Within towns on collector roads, overall belt use was 59.0 percent, while rates on more rural between-town arterials was 51.0 percent.

Three of the areas had multiple reservations. The Northern Plains area had the five lowest belt use rates and averaged just 27.6 percent belt use across all five. Great Lakes and Northwest had the highest belt use; 3 of the 4 reservations in those two areas had the highest individual belt use rates observed. Of the 5 reservations in the Southwest, 3 had moderate belt use figures, while the other 2 had rates above 75 percent, among the highest for tribal reservations.

Another indication of belt use is the kind of safety belt law. There are two kinds of belt use laws that may affect use rates: the safety belt law of the reservation itself and the safety belt law of the State in which the tribal reservation is located. Data were examined in both ways. Nine reservations had primary safety belt laws; in them, 68.6 percent of vehicle occupants were belted. By comparison, 3 tribal reservations had secondary belt laws; they averaged 53.2 percent belt use. For the 4 reservations with no belt use laws of any kind, only 26.4 percent of the vehicle occupants were belted.