Citation

Cooper S, Chakravarthy B, Anderson CL, Hata S, Ferrer C, Lotfipour S. Ann. Emerg. Med. 2011; 58(4): S322.

Copyright

(Copyright © 2011, American College of Emergency Physicians, Publisher Elsevier Publishing)

DOI

10.1016/j.annemergmed.2011.06.458

PMID

unavailable

Abstract

Study Objectives
Our study seeks to determine if light emitting diode (LED) billboards lead to an increase in the number of motor vehicle traffic collisions.
Methods
We evaluated crashes within a 1000 ft radius of 39 LED billboards in Los Angeles before and after billboard implementation, as well as collisions outside of this radius on the same street. From the Los Angeles Department of Building and Safety we obtained the locations and date of finalization of the 39 LED billboards in Los Angeles from May 31, 2007 through June 17, 2008. Through direct field observation of random locations, we selected a radius of 1000 ft as a standard for driver "distractibility" for all billboards. Collision data was obtained from the Statewide Integrated Traffic Record System of the California Highway Patrol and geocoded. We compared collisions in the year before May 31, 2007 to those in the year after June 17, 2008. We calculated risk ratios and confidence limits, assuming a Poisson distribution.
Results
Ninety-eight percent of crashes on the 33 streets with billboards were geocoded. In the pre-LED period (5/31/06-5/30/07) there were 600 crashes within 1000 ft and 7247 crashes on the 33 streets. In the post-LED period (6/18/08-06/17/09), there were 596 crashes within 1000 ft and 6642 crashes on the 33 streets. The risk ratio comparing crashes near the billboards, controlling for crashes on the 33 streets, was 1.08 (95%CI 0.97-1.21). If this increase was due to the billboards, there were 50 excess crashes, or 1.4 crashes per billboard.
Conclusion
There was a trend towards an increased ratio of crashes within the distractible geographic area, which may put drivers at increased risk around the billboards. But the absolute number of crashes decreased after LED billboard implementation, perhaps due to changes in traffic volume. Future research should consider the direction the billboard faces and the direction of traffic flow.

Language: en