Objective: The aims of this research were to cross-sectional survey the basic characteristics of the seat belts usage and use rate among drivers and passengers in Thailand. And, study the relationship between seat belt use rate and gross provincial product (GPP), literacy levels, percent under the poverty line and police density, relationships between literacy levels and penalties rate.

Materials and Methods: A nationwide cross-sectional study was conducted by a collaboration of police department, injury surveillance of the Ministry of Public Health, Thai Road Safety Survey, and National Pediatric Injury and Trauma Registry of Thailand (NPIRT) database from 2010 to 2011.The rates of seat belt usage were recorded. All baseline characteristic variables (regions, provinces, population density, police density, literacy level, under poverty line, and conviction rate) were collected, and compared with interested outcome, seat belt usage rate by univariate analysis, linear regression and multiple regression analysis.

Results: The average of seat belt usage rate across the country was 37.8 %+15.3 %. The highest rate of usage (mean±SD) were demonstrated in Bangkok (78.9 %), follow by North-east region (46.2 %+12.5 %), Central region (44.0 %+11.9 %), Northern region (28.2 %+9.7 %), and lowest in Southern region (24.2 %+11.1 %), respectively. The univariate regression analyses, GPP (coefficient 0.303;95%CI :0.109-0.497), literacy (coefficient 0.044;95%CI:0.020-0.068), police density (coefficient 0.038;95%CI: 0.0170-0.060) and conviction rate (coefficient 0.008;95%CI:0.003-0.012) showed statistically significances with seat belt usage rate (p-value=0.003, 0.010, <0.001, 0.001, respectively). The level of literacy not significant correlated to decrease of conviction rate (coefficient 0.001;95% CI: -1.15-1.38, p-value=0.86). Multiple regression analyses, results showed the final three significantly correlated factors with usage rate were GPP, level of literacy, and conviction rate (p-value < 0.001, adjusted R-square 0.33). GPP showed a highest impact on seat-belt usage rate. 19.5 % (coefficient 0.195; 95%CI:0.025-0.366, p-value = 0.03). The level of literacy of the population enhance the rate of seat-belt usage approximately 3.9 %(coefficient 0.039; 95 % CI :0.019-0.060, p-value <0.001), and conviction rate can increase seat belt usage rate 0.64 %(coefficient 0.006; 95 % CI 0.003-0.010, p-value< 0.01).

Conclusion: Only one third of people use a seat belt when they drive in Thailand. The seat belt usage rate has a trend of increasing in urban more than rural area, and the highest rate in the metropolitan’s area. Finally, three significantly factors were GPP, level of literacy, and conviction rate had significant effect with rate seat belt usage. Improving of GPP, Level of Literacy and law penalty will be enhancing of seat belt usage rate and their engagement in immediate and long term.

Keywords: Seat Belt, Road Traffic Collision, Seat belt Compliance, Seat Belt Law legislation