Protection of the cervical spine is recommended following multisystem injury. In 2021, Ambulance Victoria changed clinical practice guidelines to apply soft collars instead of semi-rigid collars for suspected cervical spine injury. The aim of this study was to describe associated changes in imaging practices and diagnoses of pressure sores, hospital acquired pneumonia, and spinal cord injury. A retrospective pre- and postintervention study was conducted including all consecutive patients that presented to an adult major trauma center in Melbourne, Australia with a cervical collar placed by emergency medical services over two 3-month periods. There were 1762 patients included. A computed tomography (CT) of the cervical spine was performed in 795 (88.4%) patients in the semi-rigid collar period and 810 (93.8%) in the soft collar period (p=0.001). Soft collars were associated with higher rates of clearance of the cervical spine in the emergency department (ED) (odds ratio [OR] 4.14; 95% confidence interval [CI]: 3.36-5.09). There were no differences in diagnosis of pressure sores (0.11%vs. 0.23%, p=0.97) or hospital acquired pneumonia (2.0%vs. 2.7%; p=0.44) or cervical spinal cord injury (0.45%vs. 0.81%; p=0.50). Following a change from prehospital semi-rigid collars to soft collars, more patients were investigated with a CT scan and more frequent clearance of the cervical spine occurred in the ED. There were no differences in the rates of spinal cord injuries, pressure sores or hospital acquired pneumonia, but the study was underpowered to detect significant differences. The practice of soft collars for prehospital care of patients with suspected neck injury requires ongoing surveillance.