Effect of Seat Belt Use on Injury Severity for Adult Rear-Seat Occupants Injured in Motor Vehicle Crashes_17-SPR0-011

In the State of Iowa passengers age 18 and older are not required by law to use seat belts when they ride in the back seat of a motor vehicle. Only 23.1% of adult rear-seat passengers involved in fatal crashes in Iowa from 2013-2019 were belted compared to 70.5% of adult front-seat passengers. This project aimed to estimate and compare the costs of traumatic injuries suffered by adult rear-seat occupants based on reported seat belt use. After access to the trauma data was impacted by the COVID-19 pandemic, a new data source was identified that consisted of Iowa hospital data that had been probabilistically linked to injured individuals in Iowa crash reports. However, due to low confidence in the quality of the data linkage, all results relating to the costs of injuries and length of stay in the hospital should be considered preliminary findings. From 2016-2019, a total of 1,646 adult occupants seated in rear positions in passenger vehicles who were reported to be injured were identified from the Iowa crash data system. Ordinal regression models were used to calculate odds ratios for seat belt use while controlling for several covariates, including age, gender, vehicle damage, speed limit, crash type, and time of day. Injured adult occupants in the rear seat who were not belted were 6.2 times more likely to have a fatal injury compared to lower levels of injury and 3.6 times more likely to have a fatal or serious injury compared to a minor or possible injury. Occupants were 1.9 times more likely to receive a higher level of transport to medical care compared to those who were belte