Objective: To describe the characteristics and associated occupant injuries of motor vehicle collisions (MVCs) involving ambulances as compared with MVCs involving similar-sized vehicles.

Methods: Motor vehicle crash data in Pennsylvania from 1997-2001 were analyzed to compare the characteristics of crashes involving ambulances with those involving vehicles of a similar size. Crash demographics (e.g., location of crash, roadway conditions, intersection type) and associated injuries were examined and compared using chi-square tests and Fisher's exact test.

Results: 2,038 ambulance MVCs and 23,155 crashes involving similar-sized vehicles were identified. Weather and road surface conditions were similar, but ambulance MVCs occurred with increased frequency on evenings and weekends. Ambulances were more likely to be involved in four-way intersection crashes (43% vs. 23%, p = 0.001), angled collisions (45% vs. 29%, p = 0.001), and collisions at traffic signals (37% vs. 18%, p = 0.001). More people were involved in ambulance MVCs (p = 0.001), with 84% of ambulance MVCs involving three or more people and 33% involving five or more people. Injuries were reported in more ambulance MVCs (76% vs. 61%, p = 0.001). Pedestrian involvement was rare (< 5% in both groups).

Conclusion: Ambulance crashes occur more frequently at intersections and traffic signals and involve more people and more injuries than those of similar-sized vehicles.