Citation

Cofone J, Rich A, Scott J. Accid. Reconstr. J. 2007; 17(6): 19-27.

Copyright

(Copyright © 2007, Accident Reconstruction Journal)

DOI

unavailable

PMID

unavailable

Abstract

Passenger vehicle frontal impacts with narrow fixed objects such as utility poles and trees are a common event. Such impacts represent a large segment of fixed-object crashes routinely investigated by accident reconstructionists. Narrow object crash testing is occasionally conducted in a laboratory setting, with data from many, if not most, of these tests not within the public domain and therefore, not available to most crash reconstructionists. Additionally, a large percentage of these crashes employ the use of rigid pole barriers. In these pole impact crash tests, the assumption is often made that the vehicle absorbs all the crash energy during impact. This type of testing may be appropriate when the goal of such testing is the evaluation of vehicle crashworthiness; however, as is often the case, poles, and to a lesser extent, trees struck in the real world often fracture and/or move. Such fracture and movement is an indication that poles and trees absorb some amount of the crash energy. This form of energy absorption should be considered in analysis of these crashes. Additionally, and to the extent possible, any post-impact energy possessed by the vehicle should also be considered. Several equations for estimating vehicle speeds in frontal impacts with narrow objects such as utility poles, which are based on maximum residual frontal crush, have been presented in the literature. This paper compares these methods as well as a relatively newer method known as the Vomhof method. Eight full-scale crash tests were conducted at known speeds. Maximum static crush was measured as required by each of the equations. Computations were performed and results then compared to the known impact speed. The equations were also applied to a narrow object real-world crash which involved a model year 2006 vehicle, wherein data from the vehicle's Event Data Recorder was obtained. Results of this crash were consistent with results from the crash tests that involved older vehicles.