Background: While studies, mostly from Europe and Australia, have examined the effect of speed cameras on motor vehicle collisions, limited data exist regarding their impact on charges and number of patients taken to Level 1 trauma centers (L1TCs). Because of conflicting perceptions and data on their value, speed cameras were implemented along select Arizona highways in 2008 but then removed in 2010. The hypotheses of our study were twofold. (1) Speed cameras reduce admissions to L1TCs, and (2) speed cameras reduce crash kinetic energy, resulting in lower Injury Severity Score (ISS), mortality, hospital costs, and length of stay (LOS).
Methods: A retrospective review of all patients admitted to L1TCs who were injured in motor vehicle crashes along a 26-mile segment of interstate I-10 in urban Phoenix was performed. Patients were identified using both the Arizona State Trauma Registry and the Arizona Department of Transportation collision data for 2009 to 2011. This specific 26-mile segment of I-10 was selected because it contained at least one speed camera within 1 mile along its entire length from October 2008 to October 2010. Two time frames were evaluated: January 1 to December 31, 2009, when cameras were in place (2009 camera group) and January 1 to December 31, 2011, when no cameras were in place (2011 no-camera group). Variables analyzed include number of collisions, number of injuries, on-scene mortality, trauma center admissions, number of collisions with admissions, in-hospital mortality, ISS, hospital charges, LOS, age, sex, race, and ethnicity. Five confounding variables were eliminated. Analysis was performed using Fisher's exact test and linear regression.
Results: Camera removal was associated with a twofold increase in L1TC admissions as well as increased resource use. There were no significant differences between the two time frames for ISS, mortality, median charges, or median LOS.
Conclusion: In this study, removal of speed cameras resulted in increased trauma center admissions and resource use.
Level of evidence: Care management study, level IV.